ALBERT

Description: In the effective action approach the imaginary part of the triple pomeron amplitude is calculated. The found dependence on the longitudinal momentum transfer $$e_{-}$$e- is found to separate as a simple factor $$1/|e_{-}|$$1/|e-|. This result is used to calculate the high-mass diffraction on a hadron and double scattering cross-section off a composite target.

Description: We for the first time obtain the analytical solution for the quirk equation of motion in an approximate way. Based on it, we study several features of quirk trajectory in a more precise way, including quirk oscillation amplitude, number of periods, as well as the thickness of quirk pair plane. Moreover, we find an exceptional case where the quirk crosses at least one of the tracking layers repeatedly. Finally, we consider the effects of ionization energy loss and fixed direction of infracolor string for a few existing searches.

Description: We define jet transition values for the anti-$$k_{ ot }$$k⊥ algorithm for both hadron and $$e^+e^-$$e+e- colliders. We show how these transition values can be computed and how they can be used to improve the performance of clusterization when jet resolution parameters are varied over a larger set of values. Finally we present a simple performance test to illustrate the behavior of the new method compared to the original one.

Description: Motivated by the recent studies of the novel asymptotically global $$hbox {AdS}_4$$AdS4 black hole with deformed horizon, we consider the action of Einstein–Maxwell gravity in AdS spacetime and construct the charged deforming AdS black holes with differential boundary. In contrast to deforming black hole without charge, there exists at least one value of horizon for an arbitrary temperature. The extremum of temperature is determined by charge q and divides the range of temperature into several parts. Moreover, we use an isometric embedding in the three-dimensional space to investigate the horizon geometry. The entropy and quasinormal modes of deforming charged AdS black hole are also studied in this paper. Due to the existence of charge q, the phase diagram of entropy is more complicated. We consider two cases of solutions: (1) fixing the chemical potential $$mu $$μ; (2) changing the value of $$mu $$μ according to the values of horizon radius and charge. In the first case, it is interesting to find there exist two families of black hole solutions with different horizon radii for a fixed temperature, but these two black holes have same horizon geometry and entropy. The second case ensures that deforming charged AdS black hole solutions can reduce to standard RN–AdS black holes.

Description: New phenomenological implications of the Generalized Uncertainty Principle (GUP), a modification of the Heisenberg Uncertainty Principle (HUP) are explored in light of constraints arising from underground experiments. An intimate link intertwines the symplectic structure of a theory, which is at the very base of the formulation of the HUP and thus a pillar of quantum mechanics, with the symmetries of space-time and the spin-statistics. Within this wide framework, a large class of non-perturbative GUPs inevitably lead to energy-dependent violations of the total angular momentum conservation rules, and imply hence tiny Pauli Exclusion Principle (PEP) violating transitions. Exotic PEP violating nuclear transitions can be tested, for example, through extremely high precision data provided by the DAMA/LIBRA experiment. We show that several GUP violations are already ruled out up to the quantum gravity Planck scale.

Description: We propose to accommodate economically the type-II neutrino seesaw mechanism in (G)NMSSM from GMSB and AMSB, respectively. The heavy triplets within neutrino seesaw mechanism are identified to be the messengers. Therefore, the $$mu $$μ-problem, the neutrino mass generation, LFV as well the soft SUSY breaking parameters can be economically combined in a non-trivial way. General features of such extensions are discussed. The type-II neutrino seesaw-specific interactions can give additional Yukawa deflection contributions to the soft SUSY breaking parameters of NMSSM, which are indispensable to realize successful EWSB and accommodate the 125 GeV Higgs. Relevant numerical results, including the constraints of dark matter and possible LFV processes $$l_i ightarrow l_j gamma $$li→ljγ etc, are also given. We find that our economical type-II neutrino seesaw mechanism extension of NMSSM from AMSB or GMSB can lead to realistic low energy NMSSM spectrum, both admitting the 125 GeV Higgs as the lightest CP-even scalar. The possibility of the 125 GeV Higgs being the next-to-lightest CP-even scalar in GMSB-type scenario is ruled out by the constraints from EWSB, collider and precision measurements. The possibility of the 125 GeV Higgs being the next-to-lightest CP-even scalar in AMSB-type scenario is ruled out by dark matter direct detection experiments. Possible constraints from LFV processes $$l_i ightarrow l_j gamma $$li→ljγ can give an upper bound for the messenger scale.

Description: It has been observed in the literature that measurements of low-mass Drell–Yan (DY) transverse momentum spectra at low center-of-mass energies $$sqrt{s}$$s are not well described by perturbative QCD calculations in collinear factorization in the region where transverse momenta are comparable with the DY mass. We examine this issue from the standpoint of the Parton Branching (PB) method, combining next-to-leading-order (NLO) calculations of the hard process with the evolution of transverse momentum dependent (TMD) parton distributions. We compare our predictions with experimental measurements at low DY mass, and find very good agreement. In addition we use the low mass DY measurements at low $$sqrt{s}$$s to determine the width $$q_s$$qs of the intrinsic Gauss distribution of the PB-TMDs at low evolution scales. We find values close to what has earlier been used in applications of PB-TMDs to high-energy processes at the Large Hadron Collider (LHC) and HERA. We find that at low DY mass and low $$sqrt{s}$$s even in the region of $$p_mathrm{T}/m_mathrm{DY}sim 1$$pT/mDY∼1 the contribution of multiple soft gluon emissions (included in the PB-TMDs) is essential to describe the measurements, while at larger masses ($$m_mathrm{DY}sim m_{{mathrm{Z}}}$$mDY∼mZ) and LHC energies the contribution from soft gluons in the region of $$p_mathrm{T}/m_mathrm{DY}sim 1$$pT/mDY∼1 is small.

Description: We develop a method for computing the Bogoliubov transformation experienced by a confined quantum scalar field in a globally hyperbolic spacetime, due to the changes in the geometry and/or the confining boundaries. The method constructs a basis of modes of the field associated to each Cauchy hypersurface, by means of an eigenvalue problem posed in the hypersurface. The Bogoliubov transformation between bases associated to different times can be computed through a differential equation, which coefficients have simple expressions in terms of the solutions to the eigenvalue problem. This transformation can be interpreted physically when it connects two regions of the spacetime where the metric is static. Conceptually, the method is a generalisation of Parker’s early work on cosmological particle creation. It proves especially useful in the regime of small perturbations, where it allows one to easily make quantitative predictions on the amplitude of the resonances of the field, providing an important tool in the growing research area of confined quantum fields in table-top experiments. We give examples within the perturbative regime (gravitational waves) and the non-perturbative regime (cosmological particle creation). This is the first of two articles introducing the method, dedicated to spacetimes without boundaries or which boundaries remain static in some synchronous gauge.

Description: In this paper, we study four-dimensional topological black hole solutions of Einsteinian cubic gravity in the presence of nonlinear Born–Infeld electrodynamics and a bare cosmological constant. First, we obtain the field equations which govern our solutions. Employing Abbott–Deser–Tekin and Gauss formulas, we present the expressions of conserved quantities, namely total mass and total charge of our topological black solutions. We disclose the conditions under which the model is unitary and perturbatively free of ghosts with asymptotically (A)dS and flat solutions. We find that, for vanishing bare cosmological constant, the model is unitary just for asymptotically flat solutions, which only allow horizons with spherical topology. We compute the temperature for these solutions and show that it always has a maximum value, which decreases as the values of charge, nonlinear coupling or cubic coupling grows. Next, we calculate the entropy and electric potential. We show that the first law of thermodynamics is satisfied for spherical asymptotically flat solutions. Finally, we peruse the effects of model parameters on thermal stability of these solutions in both canonical and grand canonical ensembles.

Description: We present a systematic investigation of jet production at hadron colliders from a phenomenological point of view, with the dual aim of providing a validation of theoretical calculations and guidance to future determinations of parton distributions (PDFs). We account for all available inclusive jet and dijet production measurements from ATLAS and CMS at 7 and 8 TeV by including them in a global PDF determination, and comparing to theoretical predictions at NNLO QCD supplemented by electroweak (EW) corrections. We assess the compatibility of the PDFs, specifically the gluon, obtained before and after inclusion of the jet data. We compare the single-inclusive jet and dijet observables in terms of perturbative behaviour upon inclusion of QCD and EW corrections, impact on the PDFs, and global fit quality. In the single-inclusive case, we also investigate the role played by different scale choices and the stability of the results upon changes in modelling of the correlated experimental systematics.

Description: In this paper, we present a detailed analysis of the dark energy dipole using Union2, Pantheon and GRB dataset in Chameleon and Teleparallel dark energy models, in comparison with $$Lambda $$ΛCDM. Both models are extensively studied in recent years and our result shows that with Union2 and Pantheon data, the preferred direction of the anisotropy in both models are very close to each other as well as with those obtained in some studies for $$Lambda $$ΛCDM. However, when the models fitted with a combination of Union 2 and GRB, the statistical analysis slightly favors the Chameleon cosmology over Teleparallel gravity, with the maximum anisotropic direction of $$(l = 330^{+30}_{-28}$$(l=330-28+30, $$b = -15^{+23}_{-25})$$b=-15-25+23) in galactic coordinate system, comparable with $$alpha $$α-dipole result in Keck-VLT data and LCDM.

Description: We study charged black hole solutions in 4-dimensional (4D) Einstein–Gauss–Bonnet–Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes an upper bound on the Gauss–Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss–Bonnet coupling constant $$alpha _{GB}$$αGB to be bounded by $$alpha _{GB}le 0$$αGB≤0 as $$D ightarrow 4$$D→4.

Description: Parametrizations of equation of state parameter as a function of the scale factor or redshift are frequently used in dark energy modeling. The question investigated in this paper is if parametrizations proposed in the literature are compatible with the dark energy being a barotropic fluid. The test of this compatibility is based on the functional form of the speed of sound squared, which for barotropic fluid dark energy follows directly from the function for the Equation of state parameter. The requirement that the speed of sound squared should be between 0 and speed of light squared provides constraints on model parameters using analytical and numerical methods. It is found that this fundamental requirement eliminates a large number of parametrizations as barotropic fluid dark energy models and puts strong constraints on parameters of other dark energy parametrizations.

Description: The boundary state corresponding to the Dp-brane with a transverse rotation in the presence of the Kalb–Ramond and tachyon background fields and a U(1) internal field will be constructed. We shall investigate effects of the open string tachyon condensation on this brane via its boundary state. We demonstrate that the background fields and transverse rotation cannot protect the brane against the collapse. Our calculations are in the context of the bosonic string theory.

Description: Gravitational wave (GW) data can be used to test the parity symmetry of gravity by investigating the difference between left-hand and right-hand circular polarization modes. In this article, we develop a method to decompose the circular polarizations of GWs produced during the inspiralling stage of compact binaries, with the help of stationary phase approximation. The foremost advantage is that this method is simple, clean, independent of GW waveform, and is applicable to the existing detector network. Applying it to the mock data, we test the parity symmetry of gravity by constraining the velocity birefringence of GWs. If a nearly edge-on binary neutron-stars with observed electromagnetic counterparts at 40 Mpc is detected by the second-generation detector network, one could derive the model-independent test on the parity symmetry in gravity: the lower limit of the energy scale of parity violation can be constrained within $$mathcal {O}(10^4mathrm{eV})$$O(104eV).

Description: In this article, we elaborate further on the $$varLambda $$ΛCDM “tension”, suggested recently by the authors Lusso et al. (Astron Astrophys 628:L4, 2019) and Risaliti and Lusso (Nat Astron 3(3):272, 2019). We combine Supernovae type Ia (SNIa) with quasars (QSO) and Gamma Ray Bursts (GRB) data in order to reconstruct in a model independent way the Hubble relation to as high redshifts as possible. Specifically, in the case of either SNIa or SNIa/QSO data we find that the current values of the cosmokinetic parameters extracted from the Gaussian process are consistent with those of $$varLambda $$ΛCDM. Including GRBs in the analysis we find a tension, which lies between $$2sigma $$2σ and $$3sigma $$3σ levels respectively. Finally, we find that at high redshifts ($$z〉1$$z〉1) the corresponding cosmokinetic parameters significantly deviate from those of $$varLambda $$ΛCDM, hence the possibility of new Physics is not precluded by the present analysis.

Description: While the prompt $$mathrm{J}/psi $$J/ψ cross section and polarization have been measured with good precision as a function of transverse momentum, $$p_mathrm{T}$$pT, those of the directly produced $$mathrm{J}/psi $$J/ψ are practically unknown, given that the cross sections and polarizations of the $$chi _{{c}1} $$χc1 and $$chi _{{c}2} $$χc2 mesons, large indirect contributors to $$mathrm{J}/psi $$J/ψ production, are only known with rather poor accuracy. The lack of precise measurements of the $$chi _{{c}J} $$χcJ polarizations induces large uncertainties in the level of their feed-down contributions to the prompt $$mathrm{J}/psi $$J/ψ yield, because of the polarization-dependent acceptance corrections. The experimental panorama of charmonium production can be significantly improved through a consistent and model-independent global analysis of existing measurements of $$mathrm{J}/psi $$J/ψ, $$psi mathrm{(2S)}$$ψ(2S) and $$chi _{c}$$χc cross sections and polarizations, faithfully respecting all the correlations and uncertainties. In particular, it is seen that the $$chi _{{c}J} $$χcJ polarizations and feed-down fractions to $$mathrm{J}/psi $$J/ψ production have a negligible dependence on the $$mathrm{J}/psi $$J/ψ$$p_mathrm{T}$$pT, with average values $$lambda _vartheta ^{chi _{{c}1}} = 0.55 pm 0.23$$λϑχc1=0.55±0.23, $$lambda _vartheta ^{chi _{{c}2}} = -0.39 pm 0.22$$λϑχc2=-0.39±0.22, $$R^{chi _{{c}1}} = (18.8 pm 1.4)\%$$Rχc1=(18.8±1.4)% and $$R^{chi _{{c}2}} = (6.5 pm 0.5)\%$$Rχc2=(6.5±0.5)%. The analysis also shows that $$(67.2 pm 1.9)$$(67.2±1.9)% of the prompt $$mathrm{J}/psi $$J/ψ yield is due to directly-produced mesons, of polarization constrained to remarkably small values, $$lambda _vartheta ^{mathrm{J}/psi } = 0.04 pm 0.06$$λϑJ/ψ=0.04±0.06.

Description: A significant fraction of cosmological dark matter can be formed by very dense macroscopic objects, for example primordial black holes. Gravitational waves offer a promising way to probe these kinds of dark-matter candidates, in a parameter space region that is relatively untested by electromagnetic observations. In this work we consider an ensemble of macroscopic dark matter with masses in the range $$10^{-13}$$10-13–$$1 M_{odot }$$1M⊙ orbiting a super-massive black hole. While the strain produced by an individual dark-matter particle will be very small, gravitational waves emitted by a large number of such objects will add incoherently and produce a stochastic gravitational-wave background. We show that LISA can be a formidable machine for detecting the stochastic background of such objects orbiting the black hole in the centre of the Milky Way, Sgr $$mathrm{A}^{!*}$$A∗, if a dark-matter spike of the type originally predicted by Gondolo and Silk forms near the central black hole.

Description: Obtaining a lattice-consistent result for the temperature dependence of the QCD conformal anomaly from a top-down M-theory dual (valid) for all temperatures – both, $$TTc – of thermal QCD at intermediate gauge coupling, has been missing in the literature. We fill this gap by addressing this issue from the M-theory uplift of the SYZ type IIA mirror at intermediate gauge/string coupling [both obtained in Dhuria et al. (JHEP 1311:001, 2013)] of the UV-complete type IIB holographic dual of large-N thermal QCD of Mia et al. (Nucl Phys B 839:187, 2010), and comparing with the very recent lattice results of Bazavov et al. (Phys Rev D 97(1):014510, 2018). Estimates of the $$mathcal{O}(R^4)$$O(R4) higher derivative corrections in the $$D=11$$D=11 supergravity action relevant to considering the aforementioned M theory uplift in the intermediate ’t Hooft coupling (in addition to gauge coupling) limit, are also presented. We also show that after a tuning of the (small) Ouyang embedding parameter and radius of a blown-up $$S^2$$S2 when expressed in terms of the horizon radius, a QCD deconfinement temperature $$T_c=150$$Tc=150 MeV from a Hawking–Page phase transition at vanishing baryon chemical potential consistent with lattice QCD in the heavy-quark limit, can be obtained.

Description: We propose a method of projecting the quantum states from a state space of a given geometry into another state space generated by a different geometry, taking care of the correct normalization which is crucial in interpreting the quantum theory. Thanks to this method we can define on any spatially flat FLRW spacetime states in which genuine Minkowskian parameters are measured. We use these Minkowskian states for separating the frequencies in the rest frames of the massive scalar particles defining thus the scalar rest frame vacuum. We show that this vacuum is stable on the de Sitter expanding universe where the energy is conserved. In contrast, on a spatially flat FLRW spacetime with a Milne-type scale factor this vacuum is found to be dynamic, corresponding to a time-dependent rest energy interpreted as an effective mass. This dynamic vacuum gives rise to cosmological particle creation which is significant only in the early Milne-type universe considered here. Some interesting features of this new effect are pointed out in a brief analysis.

Description: We study 3-jet event topologies in proton-proton collisions at a centre-of-mass energy of $$sqrt{s} = 13 mathrm{ TeV}$$s=13TeV in a configuration, where one jet is present in the central pseudorapidity region ($$|eta | 〈 2.0$$|η| 2.0$$|η|〉2.0). We compare various parton level predictions using: collinear factorisation, $$k_mathrm{T}$$kT-factorisation with fully off-shell matrix elements and the hybrid framework. We study the influence of different parton distribution functions, initial state radiation, final state radiation, and hadronisation. We focus on differential cross sections as a function of azimuthal angle difference between the leading dijet system and the third jet, which is found to have excellent sensitivity to the physical effects under study.

Description: Poincaré gauge theories provide an approach to gravity based on the gauging of the Poincaré group, whose homogeneous part generates curvature while the translational sector gives rise to torsion. In this note we revisit the stability of the widely studied quadratic theories within this framework. We analyse the presence of ghosts without fixing any background by obtaining the relevant interactions in an exact post-Riemannian expansion. We find that the axial sector of the theory exhibits ghostly couplings to the graviton sector that render the theory unstable. Remarkably, imposing the absence of these pathological couplings results in a theory where either the axial sector or the torsion trace becomes a ghost. We conclude that imposing ghost-freedom generically leads to a non-dynamical torsion. We analyse however two special choices of parameters that allow a dynamical scalar in the torsion and obtain the corresponding effective action where the dynamics of the scalar is apparent. These special cases are shown to be equivalent to a generalised Brans–Dicke theory and a Holst Lagrangian with a dynamical Barbero–Immirzi pseudoscalar field respectively. The two sectors can co-exist giving a bi-scalar theory. Finally, we discuss how the ghost nature of the vector sector can be avoided by including additional dimension four operators.

Description: This paper describes precision measurements of the transverse momentum $$p_mathrm {T}^{ell ell }$$pTℓℓ ($$ell =e,mu $$ℓ=e,μ) and of the angular variable $$phi ^{*}_{eta }$$ϕη∗ distributions of Drell–Yan lepton pairs in a mass range of 66–116 GeV. The analysis uses data from 36.1 fb$$^{-1}$$-1 of proton–proton collisions at a centre-of-mass energy of $$sqrt{s}=13,$$s=13TeV collected by the ATLAS experiment at the LHC in 2015 and 2016. Measurements in electron-pair and muon-pair final states are performed in the same fiducial volumes, corrected for detector effects, and combined. Compared to previous measurements in proton–proton collisions at $$sqrt{s}=7$$s=7 and $$8,$$8TeV, these new measurements probe perturbative QCD at a higher centre-of-mass energy with a different composition of initial states. They reach a precision of 0.2$$\%$$% for the normalized spectra at low values of $$p_mathrm {T}^{ell ell }$$pTℓℓ. The data are compared with different QCD predictions, where it is found that predictions based on resummation approaches can describe the full spectrum within uncertainties.

Description: We construct models with the Gauss–Bonnet term multiplied by a function of the scalar field leading to an inflationary scenario. The consideration is related to the slow-roll approximation. The cosmological attractor approach gives the spectral index of scalar perturbations which is in a good agreement with modern observation and allows for variability of the tensor-to-scalar ratio. We reconstruct models with variability of parameters, which allows one to reproduce cosmological attractor predictions for inflationary parameters in an approximation of the leading order of 1/N in Einstein–Gauss–Bonnet gravity.

Description: We investigate static and spherically symmetric solutions in a gravity theory that extends the standard Hilbert–Einstein action with a Lagrangian constructed from a three-form field $$A_{alpha eta gamma }$$Aαβγ, which is related to the field strength and a potential term. The field equations are obtained explicitly for a static and spherically symmetric geometry in vacuum. For a vanishing three-form field potential the gravitational field equations can be solved exactly. For arbitrary potentials numerical approaches are adopted in studying the behavior of the metric functions and of the three-form field. To this effect, the field equations are reformulated in a dimensionless form and are solved numerically by introducing a suitable independent radial coordinate. We detect the formation of a black hole from the presence of a Killing horizon for the timelike Killing vector in the metric tensor components. Several models, corresponding to different functional forms of the three-field potential, namely, the Higgs and exponential type, are considered. In particular, naked singularity solutions are also obtained for the exponential potential case. Finally, the thermodynamic properties of these black hole solutions, such as the horizon temperature, specific heat, entropy and evaporation time due to the Hawking luminosity, are studied in detail.

Description: The doubly charmed $$Xi _{cc}^{++} (ccu)$$Ξcc++(ccu) state is the only listed baryon in PDG, which was discovered in the experiment. The LHCb collaboration gets closer to discovering the second doubly charmed baryon $$Xi _{cc}^{+} (ccd)$$Ξcc+(ccd), hence the investigation of the doubly charmed/bottom baryons from many aspects is of great importance that may help us not only get valuable knowledge on the nature of the newly discovered states, but also in the search for other members of the doubly heavy baryons predicted by the quark model. In this context, we investigate the strong coupling constants among the $$Xi _{cc}^{+(+)}$$Ξcc+(+) baryons and $$pi ^{0(pm )}$$π0(±) mesons by means of light cone QCD sum rule. Using the general forms of the interpolating currents of the $$Xi _{cc}^{+(+)}$$Ξcc+(+) baryons and the distribution amplitudes (DAs) of the $$pi $$π meson, we extract the values of the coupling constants $$g_{Xi _{cc} Xi _{cc} pi }$$gΞccΞccπ. We extend our analyses to calculate the strong coupling constants among the partner baryons with $$pi $$π mesons, as well, and extract the values of the strong couplings $$g_{Xi _{bb} Xi _{bb} pi }$$gΞbbΞbbπ and $$g_{Xi _{bc} Xi _{bc} pi }$$gΞbcΞbcπ. The results of this study may help experimental groups in the analyses of the data related to the strong coupling constants among the hadronic multiplets.

Description: We propose a form of gravity–matter interaction given by $$omega RT$$ωRT in the framework of f(R, T) gravity and examine the effect of such interaction in spherically symmetric compact stars. Treating the gravity–matter coupling as a perturbative term on the background of Starobinsky gravity, we develop a perturbation theory for equilibrium configurations. For illustration, we take the case of quark stars and explore their various stellar properties. We find that the gravity–matter coupling causes an increase in the stable maximal mass which is relevant for recent observations on binary pulsars.

Description: High-energy completeness of quantum electrodynamics (QED) can be induced by an interacting ultraviolet fixed point of the renormalization flow. We provide evidence for the existence of two of such fixed points in the subspace spanned by the gauge coupling, the electron mass and the Pauli spin-field coupling. Renormalization group trajectories emanating from these fixed points correspond to asymptotically safe theories that are free from the Landau pole problem. We analyze the resulting universality classes defined by the fixed points, determine the corresponding critical exponents, study the resulting phase diagram, and quantify the stability of our results with respect to a systematic expansion scheme. We also compute high-energy complete flows towards the long-range physics. We observe the existence of a renormalization group trajectory that interconnects one of the interacting fixed points with the physical low-energy behavior of QED as measured in experiment. Within pure QED, we estimate the crossover from perturbative QED to the asymptotically safe fixed point regime to occur somewhat above the Planck scale but far below the scale of the Landau pole.

Description: In this paper we investigate CP violation in charged decays of D meson. Particularly, we study the direct CP asymmetry of the Cabibbo favored non-leptonic $$D^+ ightarrow { ar{K}}^0 pi ^+$$D+→K¯0π+ and the doubly Cabibbo-suppressed decay mode $$D^+ ightarrow K^0 pi ^+$$D+→K0π+ within standard model, two Higgs doublet model with generic Yukawa structure and left right symmetric models. In the standard model, we first derive the contributions from box and di-penguin diagrams contributing to their amplitudes which are relevant to the generation of the weak phases essential for non-vanishing direct CP violation. Then, we show that the generated phases are so tiny leading to null direct CP asymmetries of both decay modes. Regarding the two Higgs doublet model with generic Yukawa structure, after taking into account all constraints on the parameter space of the model, we show that the weak phases of the amplitudes can be enhanced compared to the standard model ones. However, the enhancement is still not enough to have sizable direct CP asymmetries. Finally, within left right symmetric models, we find that $$|A^{SM+LR}_{CP} (D^+ ightarrow { ar{K}}^0 pi ^+)|lesssim mathcal {O}(10^{-3})$$|ACPSM+LR(D+→K¯0π+)|≲O(10-3) after respecting all relevant constraints on the parameter space of the model.

Description: A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of $$137{,{ext {fb}}^{-1}} $$137fb-1 at a center-of-mass energy of $$13,{ext {TeV}} $$13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as $$2.1,{ext {TeV}} $$2.1TeV for gluinos and $$0.9,{ext {TeV}} $$0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.

Description: We consider the Hamiltonian formulation of Hořava gravity in arbitrary dimensions, which has been proposed as a renormalizable gravity model for quantum gravity without the ghost problem. We study the full constraint analysis of the non-projectable Hořava gravity whose potential, $$mathcal{V}(R)$$V(R), is an arbitrary function of the (intrinsic) Ricci scalar R but without the extension terms which depend on the proper acceleration $$a_i$$ai. We find that there exist generally three distinct cases of this theory, A, B, and C, depending on (i) whether the Hamiltonian constraint generates new (second-class) constraints or just fixes the associated Lagrange multipliers, or (ii) whether the IR Lorentz-deformation parameter $${lambda }$$λ is at the conformal point or not. It is found that, for Cases A and C, the dynamical degrees of freedom are the same as in general relativity, while, for Case B, there is one additional phase-space degree of freedom, representing an extra (odd) scalar graviton mode. This would achieve the dynamical consistency of a restricted model at the fully non-linear level and be a positive result in resolving the long-standing debates about the extra graviton modes of the Hořava gravity. Several exact solutions are also studied as some explicit examples of the new constraints. The structure of the newly obtained, “extended” constraint algebra seems to be generic to Hořava gravity and its general proof would be a challenging problem. Some other challenging problems, which include the path integral quantization and the Dirac bracket quantization are discussed also.

Description: We provide a way of decoupling the first law of thermodynamics in two sectors : the standard first law of thermodynamics and the quasi first law of thermodynamics. It is showed that both sectors share the same thermodynamics volume and the same entropy. However, the total thermodynamics pressure, the total temperature and the total local energy correspond to a simple sum of the thermodynamics contributions of each sector. On the other hand, turning on the coupling constant $$alpha $$α, the total energy, given by the Noether charge, increases proportionally to this constant. Furthermore, it is showed a simple example, where, there is a phase transition between stable/unstable black hole, and, due to the application of the decoupling, it is possible to determinate that the cause of this phase transition is the behavior of the temperature at the quasi sector.

Description: We consider the prospects for measuring distinctive signatures of the CP-violating phases in the minimal supersymmetric extension of the Standard Model (MSSM) in light of the limits on sparticle masses from searches at the LHC. We use the code to evaluate model predictions and scan the parameter space using a geometric approach that maximizes CP-violating observables subject to the current upper limits on electric dipole moments (EDMs). We focus on the possible CP-violating asymmetry $$A_{mathrm{CP}}$$ACP in $$b ightarrow s gamma $$b→sγ decay and on a possible CP-violating contribution to the $$B_s - {overline{B}}_s$$Bs-B¯s mass difference $$Delta M^{NP}_{B_s}$$ΔMBsNP, as well as future measurements of the EDMs of the proton, neutron and electron. We find that the current LHC and EDM limits are consistent with values of $$A_{mathrm{CP}}$$ACP, $$Delta M^{NP}_{B_s}$$ΔMBsNP and the proton EDM that are measurable with the Belle-II detector, LHCb and a proposed measurement of the proton EDM using a storage ring, respectively. Measurement of a non-zero proton EDM would constrain $$A_{mathrm{CP}}$$ACP significantly, but it and a CP-violating contribution to $$Delta M^{NP}_{B_s}$$ΔMBsNP could still be measurable, along with neutron and electron EDMs. A more accurate measurement of $$A_{mathrm{CP}}$$ACP with the current central value would favour stop and chargino masses within reach of future LHC runs as well as a potentially measurable value of $$Delta M^{NP}_{B_s}$$ΔMBsNP.

Description: We compute the quasinormal modes (QNMs) of a massive scalar field in the background of a rotating three-dimensional Hořava AdS black hole, and we analyze the effect of the breaking of Lorentz invariance on the QNMs. Imposing on the horizon the requirements that there are only ingoing waves and at infinity the Dirichlet boundary conditions and the Neumann boundary condition hold, we calculate the oscillatory and the decay modes of the QNMs. We find that the propagation of the scalar field is stable in this background and employing the holographic principle we find the different times of the perturbed system to reach thermal equilibrium for the various branches of solutions.

Description: In the Introduction section of the original article [1].

Description: We revisit the scenario of a massive spin-2 particle as the mediator for communicating between dark matter of arbitrary spin and the Standard Model. Taking the general couplings of the spin-2 particle in the effective theory, we discuss the thermal production mechanisms for dark matter with various channels and the dark matter self-scattering. For WIMP and light dark matter cases, we impose the relic density condition and various experimental constraints from direct and indirect detections, precision measurements as well as collider experiments. We show that it is important to include the annihilation of dark matter into a pair of spin-2 particles in both allowed and forbidden regimes, thus opening up the consistent parameter space for dark matter. The benchmark models of the spin-2 mediator are presented in the context of the warped extra dimension and compared to the simplified models.

Description: The classical and quantum formulations for open systems related to dissipative dynamics are constructed on a complex hyperbolic ring, following universal symmetry principles, and considering the double thermal fields approach for modeling the system of interest, and the environment. The hyperbolic rotations are revealed as an underlying internal symmetry for the dissipative dynamics, and a chemical potential is identified as conjugate variable to the charge operator, and thus a grand partition function is constructed. As opposed to the standard scheme, there are not patologies associated with the existence of many unitarity inequivalent representations on the hyperbolic ring, since the whole of the dissipative quantum dynamics is realized by choosing only one representation of the field commutation relations. Entanglement entropy operators for the subsystem of interest and the environment, are constructed as a tool for study the entanglement generated from the dissipation. The holographic perspectives of our results are discussed.

Description: We derive new convergent series representations for the two-loop sunset diagram with three different propagator masses $$m_1,, m_2$$m1,m2 and $$m_3$$m3 and external momentum p by techniques of analytic continuation on a well-known triple series that corresponds to the Lauricella $$F_C^{(3)}$$FC(3) function. The convergence regions of the new series contain regions of interest to physical problems. These include some ranges of masses and squared external momentum values which make them useful from Chiral Perturbation Theory to some regions of the parameter space of the Minimal Supersymmetric Standard Model. The analytic continuation results presented for the Lauricella series could be used in other settings as well.

Description: We construct a two-current model. It includes two gauge fields, which introduce the doping effect, and a neutral scalar field. And then we numerically construct an AdS black brane geometry with scalar hair. Over this background, we study the fermionic system with the pseudoscalar Yukawa coupling. Some universal properties from the pseudoscalar Yukawa coupling are revealed. In particular, as the coupling increases, there is a transfer of the spectral weight from the low energy band to the high energy band. The transfer is over low energy scales but not over all energy scales. The peculiar properties are also explored. The study shows that with the increase of the doping, the gap opens more difficult. It indicates that there is a competition between the pseudoscalar Yukawa coupling and the doping.

Description: A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $$5.5

Description: The strong coupling constant $$alpha _mathrm{s}$$ α s is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic ep scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of $$alpha _mathrm{s} (m_mathrm{Z})$$ α s ( m Z ) at the Z-boson mass $$m_Z$$ m Z are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be $$alpha _mathrm{s} (m_mathrm{Z}) =0.1157,(20)_mathrm{exp},(29)_mathrm{th}$$ α s ( m Z ) = 0.1157 ( 20 ) exp ( 29 ) th . Complementary, $$alpha _mathrm{s} (m_mathrm{Z})$$ α s ( m Z ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value $$alpha _mathrm{s} (m_mathrm{Z}) =0.1142,(28)_mathrm{tot}$$ α s ( m Z ) = 0.1142 ( 28 ) tot obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.

Description: A Higgs field of particle physics can play the role of the inflaton in the early universe if it is non-minimally coupled to gravity. The Higgs inflation scenario predicts a small tensor to scalar ratio: \(r\simeq 0.003\) . Although this value is consistent with the upper bound \(r〈0.12\) given by the BICEP2/ Keck Array and Planck data, it is not at their maximum likelihood point: \(r\simeq 0.05\) . Inflationary observables depend not only on the inflationary models, but they also depend on the initial conditions of inflation. Changing the initial state of inflation can improve the value of r . In this work, we study the Higgs inflation model under general initial conditions and show that there is a subset of these general initial conditions which leads to enhancement of r . Then we show that this region of parameter space is consistent with a non-Gaussianity bound.

Description: When Morris and Thorne first proposed that traversable wormholes may be actual physical objects, they concentrated on the geometry by specifying the shape and redshift functions. This mathematical approach necessarily raises questions regarding the determination of the required stress-energy tensor. This paper discusses a natural way to obtain a complete wormhole solution by assuming that the wormhole (1) is supported by generalized Chaplygin gas and (2) admits conformal Killing vectors.

Description: In this article, we study the charmed baryon states \(\Lambda _c(2625)\) and \(\Xi _c(2815)\) with the spin-parity \({3\over 2}^-\) by subtracting the contributions from the corresponding charmed baryon states with the spin-parity \({3\over 2}^+\) using the QCD sum rules, and suggest a formula \( \mu =\sqrt{M_{\Lambda _c/\Xi _c}^2-{\mathbb {M}}_c^2}\) with the effective mass \({\mathbb {M}}_c=1.8\,\mathrm {GeV}\) to determine the energy scales of the QCD spectral densities, and make reasonable predictions for the masses and pole residues. The numerical results indicate that the \(\Lambda _c(2625)\) and \(\Xi _c(2815)\) have at least two remarkable under-structures.

Description: We study the radiative leptonic \(B_c\rightarrow \gamma \ell {\bar{\nu }}\) decays in nonrelativistic QCD effective field theory, and we explore the contribution from a fast-moving photon. As a result, interactions between the photon and the heavy quarks can be integrated out, resulting in the factorization formula for the decay amplitude. We calculate not only the relevant short-distance coefficients at leading order and next-to-leading order in \(\alpha _s\) , but also the nonrelativistic corrections at the order \(|\mathrm {v}|^2\) in our analysis. We find that the QCD corrections can significantly decrease the branching ratio, and this is of great importance in extracting the long-distance operator matrix elements of \(B_c\) . For phenomenological application, we present our results for the photon energy, lepton energy and lepton-neutrino invariant mass distribution.

Description: We point out a weak side of the commonly used determination of scalar cosmological perturbations lying in the fact that their average values can be nonzero for some matter distributions. It is shown that introduction of the finite-range gravitational potential instead of the infinite-range one resolves this problem. The concrete illustrative density profile is investigated in detail in this connection.

Description: A consistent BPS formalism to study the existence of topological axially symmetric vortices in generalized versions of the Born–Infeld–Higgs electrodynamics is implemented. Such a generalization modifies the field dynamics via the introduction of three nonnegative functions depending only in the Higgs field, namely, \(G(|\phi |)\) , \(w(|\phi |) \) , and \(V(|\phi |)\) . A set of first-order differential equations is attained when these functions satisfy a constraint related to the Ampère law. Such a constraint allows one to minimize the system’s energy in such way that it becomes proportional to the magnetic flux. Our results provides an enhancement of the role of topological vortex solutions in Born–Infeld–Higgs electrodynamics. Finally, we analyze a set of models entailing the recovery of a generalized version of Maxwell–Higgs electrodynamics in a certain limit of the theory.

Description: I put forward a qualitatively new dynamical mechanism for solving the electroweak hierarchy problem that does not require new physics at the electroweak scale. I argue that the infrared fluctuations of the gravitational field may provide a partial screening of the Higgs mass, similar to the infrared screening of the electric charge in quantum electrodynamics.

Description: It is thought that the spacetime geometry around black hole candidates is described by the Kerr solution, but an observational confirmation is still missing. Today, the continuum-fitting method and the analysis of the iron K \(\alpha \) line cannot unambiguously test the Kerr paradigm because of the degeneracy among the parameters of the system, in the sense that it is impossible with current X-ray data to distinguish a Kerr black hole from a non-Kerr object with different values of the model parameters. In this paper, we study the possibility of testing the Kerr nature of black hole candidates with X-ray spectropolarimetric measurements. Within our simplified model that does not include the effect of returning radiation, we find that it is impossible to test the Kerr metric and the problem is still the strong correlation between the spin and possible deviations from the Kerr geometry. Moreover, the correlation is very similar to that of the other two techniques, which makes the combination of different measurements not very helpful. Nevertheless, our results cannot be taken as conclusive and, in order to arrive at a final answer, the effect of returning radiation should be properly taken into account.

Description: We investigate unitarity within the complex-mass scheme, a convenient universal scheme for perturbative calculations involving unstable particles in quantum field theory which guarantees exact gauge invariance. Since this scheme requires one to introduce complex masses and complex couplings, the Cutkosky cutting rules, which express perturbative unitarity in theories of stable particles, are no longer valid. We derive corresponding rules for scalar theories with unstable particles based on Veltman’s largest-time equation and prove unitarity in this framework.

Description: We compute the decays \({B\rightarrow D^*_0}\) and \({B\rightarrow D^*_2}\) with finite masses for the b and c quarks. We first discuss the spectral properties of both the B meson as a function of its momentum and the \(D^*_0\) and \(D^*_2\) at rest. We compute the theoretical formulae leading to the decay amplitudes from the three-point and two-point correlators. We then compute the amplitudes at zero recoil of \({B\rightarrow D^*_0}\) , which turns out not to be vanishing contrary to what happens in the heavy quark limit. This opens the possibility to get better agreement with experiment. To improve the continuum limit we have added a set of data with smaller lattice spacing. The \({B\rightarrow D^*_2}\) vanishes at zero recoil and we show a convincing signal but only slightly more than 1 sigma from 0. In order to reach quantitatively significant results we plan to exploit fully smaller lattice spacings as well as another lattice regularisation.

Description: We present a simulation study of the prospects for the mass measurement of TeV-scale light-flavored right-handed squarks at a 3 TeV \(e^+e^-\) collider based on CLIC technology. In the considered model, these particles decay into their standard-model counterparts and the lightest neutralino, resulting in a signature of two jets plus missing energy. The analysis is based on full GEANT4 simulations of the CLIC_ILD detector concept, including Standard Model physics backgrounds and beam-induced hadronic backgrounds from two-photon processes. The analysis serves as a generic benchmark for the reconstruction of highly energetic jets in events with substantial missing energy. Several jet finding algorithms were evaluated, with the longitudinally invariant \(k_t\) algorithm showing a high degree of robustness towards beam-induced background while preserving the features typically found in algorithms developed for \(e^+e^-\) collisions. The presented study of the reconstruction of light-flavored squarks shows that for TeV-scale squark masses, sub-percent accuracy on the mass measurement can be achieved at CLIC.

Description: We evaluate the Hadamard function and the vacuum expectation value (VEV) of the current density for a charged scalar field, induced by flat boundaries in spacetimes with an arbitrary number of toroidally compactified spatial dimensions. The field operator obeys the Robin conditions on the boundaries and quasiperiodicity conditions with general phases along compact dimensions. In addition, the presence of a constant gauge field is assumed. The latter induces Aharonov–Bohm-type effect on the VEVs. There is a region in the space of the parameters in Robin boundary conditions where the vacuum state becomes unstable. The stability condition depends on the lengths of compact dimensions and is less restrictive than that for background with trivial topology. The vacuum current density is a periodic function of the magnetic flux, enclosed by compact dimensions, with the period equal to the flux quantum. It is explicitly decomposed into the boundary-free and boundary-induced contributions. In sharp contrast to the VEVs of the field squared and the energy-momentum tensor, the current density does not contain surface divergences. Moreover, for Dirichlet condition it vanishes on the boundaries. The normal derivative of the current density on the boundaries vanish for both Dirichlet and Neumann conditions and is nonzero for general Robin conditions. When the separation between the plates is smaller than other length scales, the behavior of the current density is essentially different for non-Neumann and Neumann boundary conditions. In the former case, the total current density in the region between the plates tends to zero. For Neumann boundary condition on both plates, the current density is dominated by the interference part and is inversely proportional to the separation.

Description: A small tensor-to-scalar ratio r may lead to distinctive phenomenology of high-scale supersymmetry. Assuming the same origin of SUSY breaking between the inflation and visible sector, we show model independent features. The simplest hybrid inflation, together with a new linear term for the inflaton field which is induced by a large gravitino mass, is shown to be consistent with all experimental data for r of order \(10^{-5}\) . For superpartner masses far above the weak scale we find that the reheating temperature after inflation might be below the value required by thermal leptogenesis if the inflaton decays to its products perturbatively, but above it if the decay is non-perturbatively instead. Remarkably, the gravitino overproduction can be evaded in such high-scale supersymmetry because of the kinematically blocking effect.

Description: We show how leading radiative corrections can be implemented in the general description of \(h\rightarrow 4\ell \) decays by means of pseudo observables (PO). With the inclusion of such corrections, the PO description of \(h\rightarrow 4\ell \) decays can be matched to next-to-leading-order electroweak calculations both within and beyond the Standard Model (SM). In particular, we demonstrate that with the inclusion of such corrections the complete next-to-leading-order SM prediction for the \(h\rightarrow 2e2\mu \) dilepton mass spectrum is recovered within \(1\,\%\) accuracy. The impact of radiative corrections for non-standard PO is also briefly discussed.

Description: A comprehensive review of physics at an \(e^+e^-\) linear collider in the energy range of \(\sqrt{s}=92\)  GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.

Description: We investigate the fragmentation instability of hairy black holes in the theory with a Gauss–Bonnet (GB) term in asymptotically flat spacetime. Our approach is through the non-perturbative fragmentation instability. By this approach, we investigate whether the initial black hole can be broken into two black holes by comparing the entropy of the initial black hole with the sum of those of two fragmented black holes. The relation between the black hole instability and the GB coupling with dilaton hair are presented. We describe the phase diagrams with respect to the mass of the black hole solutions and coupling constants. We find that a perturbatively stable black hole can be unstable under fragmentation.

Description: A pulse-shape discrimination method based on artificial neural networks was applied to pulses simulated for different background, signal and signal-like interactions inside a germanium detector. The simulated pulses were used to investigate variations of efficiencies as a function of used training set. It is verified that neural networks are well-suited to identify background pulses in true-coaxial high-purity germanium detectors. The systematic uncertainty on the signal recognition efficiency derived using signal-like evaluation samples from calibration measurements is estimated to be 5 %. This uncertainty is due to differences between signal and calibration samples.

Description: In this article, we calculate the form factors and the coupling constant of the vertex \(D_{s}^{*}D_{s}\phi \) using the three-point QCD sum rules. We consider the contributions of the vacuum condensates up to dimension 7 in the operator product expansion. And all possible off-shell cases are considered, \(\phi \) , \(D_{s}\) and \(D_{s}^{*}\) , resulting in three different form factors. Then we fit the form factors into analytical functions and extrapolate them into time-like regions, which giving the coupling constant for the process. Our analysis indicates that the coupling constant for this vertex is \(G_{D_{s}^{*}D{_{s}}\phi }=4.12\pm 0.70\,\mathrm{GeV}^{-1}\) . The results of this work are very useful in the other phenomenological analysis. As an application, we calculate the coupling constant for the decay channel \(D_{s}^{*}\rightarrow D_{s}\gamma \) and analyze the width of this decay with the assumption of the vector meson dominance of the intermediate \(\phi (1020)\) . Our final result about the decay width of this decay channel is \(\Gamma =0.59\pm 0.15\,\mathrm{keV}\) .

Description: Extensive N -body simulations are among the key means for the study of numerous astrophysical and cosmological phenomena, so various schemes are developed for possibly higher accuracy computations. We demonstrate the principal possibility for revealing the evolution of a perturbed Hamiltonian system with an accuracy independent on time. The method is based on the Laplace transform and the derivation and analytical solution of an evolution equation in the phase space for the resolvent and using computer algebra.

Description: A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5 \(\,\text {fb}^\text {-1}\) collected by the CMS experiment at the LHC in \(\mathrm {p}\mathrm {p}\) collisions at a centre-of-mass energy of 8 \(\,\hbox {TeV}\) . In order to separate the signal from the larger \(\hbox {t}\overline{\hbox {t}}\)  + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratio between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, \(\mu \) , relative to the standard model prediction for a Higgs boson mass of 125 \(\,\hbox {GeV}\) . The observed (expected) exclusion limit at a 95 % confidence level is \(\mu 〈4.2\) (3.3), corresponding to a best fit value \(\hat{\mu }=1.2^{+1.6}_{-1.5}\) .

Description: In this paper we are concerned with the effects of an anisotropic pressure on the boundary conditions of the anisotropic Lane–Emden equation and the homology theorem. Some new exact solutions of this equation are derived. Then some of the theorems governing the Newtonian perfect fluid star are extended, taking the anisotropic pressure into account.

Description: An optimized digital shaping filter has been developed for the Gerda experiment which searches for neutrinoless double beta decay in \(^{76}\) Ge. The Gerda Phase I energy calibration data have been reprocessed and an average improvement of 0.3 keV in energy resolution (FWHM) corresponding to 10 % at the \(Q\) value for \(0\nu \beta \beta \) decay in \(^{76}\) Ge is obtained. This is possible thanks to the enhanced low-frequency noise rejection of this Zero Area Cusp (ZAC) signal shaping filter.

Description: A generalisation of the narrow-width approximation (NWA) is formulated which allows for a consistent treatment of interference effects between nearly mass-degenerate particles in the factorisation of a more complicated process into production and decay parts. It is demonstrated that interference effects of this kind arising in BSM models can be very large, leading to drastic modifications of predictions based on the standard NWA. The application of the generalised NWA is demonstrated both at tree level and at one-loop order for an example process where the neutral Higgs bosons h and H of the MSSM are produced in the decay of a heavy neutralino and subsequently decay into a fermion pair. The generalised NWA, based on on-shell matrix elements or their approximations leading to simple weight factors, is shown to produce UV- and IR-finite results which are numerically close to the result of the full process at tree level and at one-loop order, where an agreement of better than \(1\,\%\) is found for the considered process. The most accurate prediction for this process based on the generalised NWA, taking into account also corrections that are formally of higher orders, is briefly discussed.

Description: A new theory of gravity called Eddington-inspired Born–Infeld (EiBI) gravity was recently proposed by Bañados and Ferreira. This theory leads to some exciting new features, such as free of cosmological singularities. In this paper, we first obtain a charged EiBI black hole solution with a nonvanishing cosmological constant when the electromagnetic field is included in. Then based on it, we study the strong gravitational lensing by the asymptotic flat charged EiBI black hole. The strong deflection limit coefficients and observables are shown to closely depend on the additional coupling parameter \(\kappa \) in the EiBI gravity. It is found that, compared with the corresponding charged black hole in general relativity, the positive coupling parameter \(\kappa \) will shrink the black hole horizon and photon sphere. Moreover, the coupling parameter will decrease the angular position and relative magnitudes of the relativistic images, while increase the angular separation, which may shine new light on testing such gravity theory in near future by the astronomical instruments.

Description: This manuscript is devoted to the investigation of the Bianchi type I universe in the context of f ( R ,  T ) gravity. For this purpose, we explore the exact solutions of locally rotationally symmetric Bianchi type I spacetime. The modified field equations are solved by assuming an expansion scalar \(\theta \) proportional to the shear scalar \(\sigma \) , which gives \(A=B^n\) , where A ,   B are the metric coefficients and n is an arbitrary constant. In particular, three solutions have been found and physical quantities are calculated in each case.

Description: By detecting redshift drift in the spectra of the Lyman- \(\alpha \) forest of distant quasars, the Sandage–Loeb (SL) test directly measures the expansion of the universe, covering the “redshift desert” of \(2 \lesssim z \lesssim 5\) . Thus this method is definitely an important supplement to the other geometric measurements and will play a crucial role in cosmological constraints. In this paper, we quantify the ability of the SL test signal by a CODEX-like spectrograph for constraining interacting dark energy. Four typical interacting dark energy models are considered: (i) \(Q=\gamma H\rho _c\) , (ii) \(Q=\gamma H\rho _{de}\) , (iii) \(Q=\gamma H_0\rho _c\) , and (iv) \(Q=\gamma H_0\rho _{de}\) . The results show that for all the considered interacting dark energy models, relative to the current joint SN  \(+\)  BAO  \(+\)  CMB  \(+\)   \(H_0\) observations, the constraints on \(\Omega _m\) and \(H_0\) would be improved by about 60 and 30–40 %, while the constraints on w and \(\gamma \) would be slightly improved, with a 30-year observation of the SL test. We also explore the impact of the SL test on future joint geometric observations. In this analysis, we take the model with \(Q=\gamma H\rho _c\) as an example, and we simulate future SN and BAO data based on the space-based project WFIRST. We find that with the future geometric constraints, the redshift drift observations would help break the geometric degeneracies in a meaningful way, thus the measurement precisions of \(\Omega _m\) , \(H_0\) , w , and \(\gamma \) could be substantially improved using future probes.

Description: To identify the nature of the newly observed charged resonance \(Z_c(4200)^+\) , we study its hadronic decays \(Z_c(4200)^+\rightarrow J/\psi \pi ^+, Z_c(4200)^+\rightarrow \eta _c\rho ^+\) and \(Z_c(4200)^+\rightarrow D^+\bar{D}^{*0}\) as a charmonium-like tetraquark state. In the framework of the QCD sum rules, we calculate the three-point functions and extract the coupling constants and decay widths for these interaction vertices. Including all these channels, the full decay width of the \(Z_c(4200)^+\) state is consistent with the experimental value reported by the Belle Collaboration, supporting the tetraquark interpretation of this state.

Description: A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at \(\sqrt{s}=8\)  TeV from pp collisions corresponding to an integrated luminosity of 20.3 fb \(^{-1}\) are examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from \(|q|=2e\) to \(|q|=6e\) are searched for. No signal candidate events are observed, and 95 % confidence level cross-section upper limits are interpreted as lower mass limits for a Drell–Yan production model. The mass limits range between 660 and 785 GeV.

Description: We study to which extent SUSY extensions of the Standard Model can describe the excess of events of 3.0 standard deviations observed by ATLAS in the on- Z signal region, respecting constraints by CMS on similar signal channels as well as constraints from searches for jets and \(E^\mathrm{miss}_\text {T}\) . GMSB-like scenarios are typically in conflict with these constraints, and do not reproduce well the shape of the \(E^\mathrm{miss}_\text {T}\) distribution of the data. An alternative scenario with two massive neutralinos can improve fits to the total number of events as well as to the \(H_\text {T}\) and \(E^\mathrm{miss}_\text {T}\) distributions. Such a scenario can be realised within the NMSSM.

Description: Leading-twist operators have a remarkable property that their divergence vanishes in a free theory. Recently it was suggested that this property can be used for an alternative technique to calculate anomalous dimensions of leading-twist operators and allows one to gain one order in perturbation theory so that, i.e., two-loop anomalous dimensions can be calculated from one-loop Feynman diagrams, etc. In this work we study the feasibility of this program by a toy-model example of the \(\varphi ^3\) theory in six dimensions. Our conclusion is that this approach is valid, although it does not seem to present considerable technical simplifications as compared to the standard technique. It does provide one, however, with a very nontrivial check of the calculation as the structure of the contributions is very different.

Description: Recently, a family of interesting analytical brane solutions were found in f ( R ) gravity with \(f(R)=R \,+\, \alpha R^2\) in Bazeia et al. (Phys Lett B 729:127 2014 ). In these solutions, the inner brane structure can be turned on by tuning the value of the parameter \(\alpha \) . In this paper, we investigate how the parameter \(\alpha \) affects the localization and the quasilocalization of the tensorial gravitons around these solutions. It is found that, in a range of \(\alpha \) , despite the brane having an inner structure, there is no graviton resonance. However, in some other regions of the parameter space, although the brane has no internal structure, the effective potential for the graviton Kaluza–Klein (KK) modes has a singular structure, and there exist a series of graviton resonant modes. The contribution of the massive graviton KK modes to Newton’s law of gravity is discussed briefly.

Description: The production of the Standard Model Higgs boson in association with a vector boson, followed by the dominant decay to \(H \rightarrow b\bar{b}\) , is a strong prospect for confirming and measuring the coupling to b -quarks in pp collisions at \(\sqrt{s}=14\)  TeV. We present an updated study of the prospects for this analysis, focussing on the most sensitive highly Lorentz-boosted region. The evolution of the efficiency and composition of the signal and main background processes as a function of the transverse momentum of the vector boson are studied covering the region 200–1000 GeV, comparing both a conventional dijet and jet substructure selection. The lower transverse momentum region (200–400 GeV) is identified as the most sensitive region for the Standard Model search, with higher transverse momentum regions not improving the statistical sensitivity. For much of the studied region (200–600 GeV), a conventional dijet selection performs as well as the substructure approach, while for the highest transverse momentum regions ( \(〉\) 600 GeV), which are particularly interesting for Beyond the Standard Model and high luminosity measurements, the jet substructure techniques are essential.

Description: Massive QED, in contrast with its massless counterpart, possesses two conserved charges; one is a screened (vanishing) Maxwell charge which is directly associated with the massive vector mesons through the identically conserved Maxwell current, while the presence of a particle-antiparticle counting charge depends on the matter. A somewhat peculiar situation arises for couplings of Hermitian matter fields to massive vector potentials; in that case the only current is the screened Maxwell current and the coupling disappears in the massless limit. In the case of self-interacting massive vector mesons the situation becomes even more peculiar in that the usually renormalizability guaranteeing validity of the first order power-counting criterion breaks down in second order and requires the compensatory presence of additional Hermitian H -fields. Some aspect of these observation have already been noticed in the BRST gauge theoretic formulation, but here we use a new setting based on string-local vector mesons which is required by Hilbert space positivity (“off-shell unitarity”). This new formulation explains why spontaneous symmetry breaking cannot occur in the presence of higher spin \(s\ge 1\)  fields. The coupling to H -fields induces Mexican hat-like self-interactions; they are not imposed and bear no relation with spontaneous symmetry breaking; they are rather consequences of the foundational causal localization properties realized in a Hilbert space setting. In the case of self-interacting massive vector mesons their presence is required in order to maintain the first order power-counting restriction of renormalizability also in second order. The presentation of the new Hilbert space setting for vector mesons which replaces gauge theory and extends on-shell unitarity to its off-shell counterpart is the main motivation for this work. The new Hilbert space setting also shows that the second order Lie-algebra structure of self-interacting vector mesons is a consequence of the principles of QFT and promises a deeper understanding of the origin of confinement.

Description: We develop a methodology for the construction of a Hessian representation of Monte Carlo sets of parton distributions, based on the use of a subset of the Monte Carlo PDF replicas as an unbiased linear basis, and of a genetic algorithm for the determination of the optimal basis. We validate the methodology by first showing that it faithfully reproduces a native Monte Carlo PDF set (NNPDF3.0), and then, that if applied to Hessian PDF set (MMHT14) which was transformed into a Monte Carlo set, it gives back the starting PDFs with minimal information loss. We then show that, when applied to a large Monte Carlo PDF set obtained as combination of several underlying sets, the methodology leads to a Hessian representation in terms of a rather smaller set of parameters (MC-H PDFs), thereby providing an alternative implementation of the recently suggested Meta-PDF idea and a Hessian version of the recently suggested PDF compression algorithm (CMC-PDFs). The mc2hessian conversion code is made publicly available together with (through LHAPDF6 ) a Hessian representations of the NNPDF3.0 set, and the MC-H PDF set.

Description: We explore a fermionic dark matter model with a possible extension of Standard Model of particle physics into two Higgs doublet model. Higgs doublets couple to the singlet fermionic dark matter through a non-renormalisable coupling providing a new physics scale. We explore the viability of such dark matter candidate and constrain the model parameter space by collider serach, relic density of DM, direct detection measurements of DM-nucleon scattering cross-section and with the experimentally obtained results from indirect search of dark matter.

Description: An overview of the flavour problem is presented, with emphasis on the theoretical efforts to find a satisfactory description of the fermion masses and the mixing angles.

Description: The production of the massive bosons \(Z^0\) and \(W^{\pm }\) could provide an excellent tool to study cold nuclear matter effects and the modifications of nuclear parton distribution functions (nPDFs) relative to the parton distribution functions (PDFs) of a free proton in high-energy nuclear reactions at the LHC as well as in heavy-ion collisions (HIC) with much higher center-of-mass energies available in the future colliders. In this paper we calculate the rapidity and transverse momentum distributions of the vector boson and their nuclear modification factors in p + Pb collisions at \(\sqrt{s_{NN}}=63\)  TeV and in Pb + Pb collisions at \(\sqrt{s_{NN}}=39\)  TeV in the framework of perturbative QCD by utilizing three parametrization sets of nPDFs: EPS09, DSSZ, and nCTEQ. It is found that in heavy-ion collisions at such high colliding energies, both the rapidity distribution and the transverse momentum spectrum of vector bosons are considerably suppressed in wide kinematic regions with respect to p + p reactions due to large nuclear shadowing effect. We demonstrate that the massive vector boson production processes with sea quarks in the initial state may give more contributions than those with valence quarks in the initial state; therefore in future heavy-ion collisions the isospin effect is less pronounced and the charge asymmetry of the W boson will be reduced significantly as compared to that at the LHC. A large difference between results with nCTEQ and results with EPS09 and DSSZ is observed in nuclear modifications of both rapidity and \(p_T\) distributions of \(Z^0\) and W in the future HIC.

Description: We present a frequentist analysis of the parameter space of the pMSSM10, in which the following ten soft SUSY-breaking parameters are specified independently at the mean scalar top mass scale \(M_\mathrm{SUSY}\equiv \sqrt{m_{\tilde{t}_{1}} m_{\tilde{t}_{2}}}\) : the gaugino masses \(M_{1,2,3}\) , the first-and second-generation squark masses \(m_{\tilde{q}_1}= m_{\tilde{q}_2}\) , the third-generation squark mass \(m_{\tilde{q}_3}\) , a common slepton mass \(m_{\tilde{\ell }}\) and a common trilinear mixing parameter A , as well as the Higgs mixing parameter \(\mu \) , the pseudoscalar Higgs mass \(M_A\) and \(\tan \beta \) , the ratio of the two Higgs vacuum expectation values. We use the MultiNest sampling algorithm with \(\sim \) 1.2 \(\times 10^9\) points to sample the pMSSM10 parameter space. A dedicated study shows that the sensitivities to strongly interacting sparticle masses of ATLAS and CMS searches for jets, leptons \(+\) signals depend only weakly on many of the other pMSSM10 parameters. With the aid of the Atom and Scorpion codes, we also implement the LHC searches for electroweakly interacting sparticles and light stops, so as to confront the pMSSM10 parameter space with all relevant SUSY searches. In addition, our analysis includes Higgs mass and rate measurements using the HiggsSignals code, SUSY Higgs exclusion bounds, the measurements of \(\mathrm{BR}(B_s \rightarrow \mu ^+\mu ^-)\) by LHCb and CMS, other B -physics observables, electroweak precision observables, the cold dark matter density and the XENON100 and LUX searches for spin-independent dark matter scattering, assuming that the cold dark matter is mainly provided by the lightest neutralino \(\tilde{\chi }^0_{1}\) . We show that the pMSSM10 is able to provide a supersymmetric interpretation of \((g-2)_\mu \) , unlike the CMSSM, NUHM1 and NUHM2. As a result, we find (omitting Higgs rates) that the minimum \(\chi ^2 = 20.5\) with 18 degrees of freedom (d.o.f.) in the pMSSM10, corresponding to a \(\chi ^2\) probability of 30.8 %, to be compared with \(\chi ^2/\mathrm{d.o.f.} = 32.8/24 \ (31.1/23) \ (30.3/22)\) in the CMSSM (NUHM1) (NUHM2). We display the one-dimensional likelihood functions for sparticle masses, and we show that they may be significantly lighter in the pMSSM10 than in the other models, e.g., the gluino may be as light as \(\sim \) 1250 \(\,\, \mathrm {GeV}\) at the 68 % CL, and squarks, stops, electroweak gauginos and sleptons may be much lighter than in the CMSSM, NUHM1 and NUHM2. We discuss the discovery potential of future LHC runs, \(e^+e^-\) colliders and direct detection experiments.

Description: We compute the corrections to the Schwarzschild metric necessary to reproduce the Hawking temperature derived from a generalized uncertainty principle (GUP), so that the GUP deformation parameter is directly linked to the deformation of the metric. Using this modified Schwarzschild metric, we compute corrections to the standard general relativistic predictions for the light deflection and perihelion precession, both for planets in the solar system and for binary pulsars. This analysis allows us to set bounds for the GUP deformation parameter from well-known astronomical measurements.

Description: LHC searches for non-standard Higgs bosons decaying into tau lepton pairs constitute a sensitive experimental probe for physics beyond the Standard Model (BSM), such as supersymmetry (SUSY). Recently, the limits obtained from these searches have been presented by the CMS collaboration in a nearly model-independent fashion – as a narrow resonance model – based on the full \(8\,\, \mathrm {TeV}\) dataset. In addition to publishing a \(95~\%~\mathrm {C.L.}\) exclusion limit, the full likelihood information for the narrow resonance model has been released. This provides valuable information that can be incorporated into global BSM fits. We present a simple algorithm that maps an arbitrary model with multiple neutral Higgs bosons onto the narrow resonance model and derives the corresponding value for the exclusion likelihood from the CMS search. This procedure has been implemented into the public computer code HiggsBounds (version 4.2.0 and higher). We validate our implementation by cross-checking against the official CMS exclusion contours in three Higgs benchmark scenarios in the Minimal Supersymmetric Standard Model (MSSM), and find very good agreement. Going beyond validation, we discuss the combined constraints of the \(\tau \tau \) search and the rate measurements of the SM-like Higgs at \(125\,\, \mathrm {GeV}\) in a recently proposed MSSM benchmark scenario, where the lightest Higgs boson obtains SM-like couplings independently of the decoupling of the heavier Higgs states. Technical details for how to access the likelihood information within HiggsBounds are given in the appendix. The program is available at http://higgsbounds.hepforge.org .

Description: We investigate inflation within \(f(R,\phi )\) -theories, where a dynamical scalar field is coupled to gravity. A class of models which can support early-time acceleration with the emerging of an effective cosmological constant at high curvature is studied. The dynamics of the field allow for exit from inflation leading to the correct amount of inflation in agreement with cosmological data. Furthermore, the spectral index and tensor-to-scalar ratio of the models are carefully analyzed. A generalization of the theory to incorporate dark matter in the context of mimetic gravity, and further extensions of the latter, are also discussed.

Description: The existence of both a minimum mass and a minimum density in nature, in the presence of a positive cosmological constant, is one of the most intriguing results in classical general relativity. These results follow rigorously from the Buchdahl inequalities in four-dimensional de Sitter space. In this work, we obtain the generalized Buchdahl inequalities in arbitrary space–time dimensions with \(\Lambda \ne 0\) and consider both the de Sitter and the anti-de Sitter cases. The dependence on D , the number of space–time dimensions, of the minimum and maximum masses for stable spherical objects is explicitly obtained. The analysis is then extended to the case of dark energy satisfying an arbitrary linear barotropic equation of state. The Jeans instability of barotropic dark energy is also investigated, for arbitrary D , in the framework of a simple Newtonian model with and without viscous dissipation, and we determine the dispersion relation describing the dark energy–matter condensation process, along with estimates of the corresponding Jeans mass (and radius). Finally, the quantum mechanical implications of the mass limits are investigated, and we show that the existence of a minimum mass scale naturally leads to a model in which dark energy is composed of a ‘sea’ of quantum particles, each with an effective mass proportional to \(\Lambda ^{1/4}\) .

Description: We study multi-soliton solutions of the four-dimensional SU(N) Skyrme model by combining the hedgehog ansatz for SU(N) based on the harmonic maps of \(S^{2}\) into \(CP^{N-1}\) and a geometrical trick which allows to analyze explicitly finite-volume effects without breaking the relevant symmetries of the ansatz. The geometric set-up allows to introduce a parameter which is related to the ’t Hooft coupling of a suitable large N limit, in which \(N\rightarrow \infty \) and the curvature of the background metric approaches zero, in such a way that their product is constant. The relevance of such a parameter to the physics of the system is pointed out. In particular, we discuss how the discrete symmetries of the configurations depend on it.

Description: The effects of color reconnection (CR) at \({\mathrm e}^+{\mathrm e}^-\) colliders are revisited, with focus on recently developed CR models. The new models are compared with the LEP2 measurements for \({\mathrm e}^+{\mathrm e}^- \rightarrow {\mathrm W}^+{\mathrm W}^- \rightarrow {\mathrm q}_1 \overline{\mathrm q}_2 {\mathrm q}_3 \overline{\mathrm q}_4\) and found to lie within their limits. Prospects for constraints from new high-luminosity \({\mathrm e}^+{\mathrm e}^-\) colliders are discussed. The novel arena of CR in Higgs decays is introduced, and it is illustrated by shifts in angular correlations that would be used to set limits on a potential CP -odd admixture of the 125 GeV Higgs state.

Description: The Lorentz transformation properties of the equal-time bound-state Bethe–Salpeter amplitude in the two-dimensional massless quantum electrodynamics (the so-called Schwinger model) are considered. It is shown that while boosting a bound state (a ‘meson’) this amplitude is subject to approximate Lorentz contraction. The effect is exact for large separations of constituent particles (‘quarks’), while for small distances the deviation is more significant. For this phenomenon to appear, the full function, i.e. with the inclusion of all instanton contributions, has to be considered. The amplitude in each separate topological sector does not exhibit such properties.

Description: The canonical Aharonov–Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov–Bohm phase acquired by a charged particle moving in time-dependent potentials. In particular, we focus on the case of a charged particle moving in the time-varying field of a plane electromagnetic wave. We work out the Aharonov–Bohm phase using both the potential (i.e. \(\oint A_\mu \mathrm{d}x ^\mu \) ) and the field (i.e. \(\frac{1}{2}\int F_{\mu \nu } \mathrm{d}\sigma ^{\mu \nu }\) ) forms of the Aharonov–Bohm phase. We give conditions in terms of the parameters of the system (frequency of the electromagnetic wave, the size of the space–time loop, amplitude of the electromagnetic wave) under which the time-varying Aharonov–Bohm effect could be observed.

Description: The LHC data on jet fragmentation function and jet shapes in PbPb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted in the frameworks of PYthia QUENched (PYQUEN) jet quenching model. A specific modification of longitudinal and radial jet profiles in most central PbPb collisions as compared with pp data is close to that obtained with PYQUEN simulations, taking into account wide-angle radiative and collisional partonic energy losses. The contribution of radiative and collisional loss to the medium-modified intra-jet structure is estimated.

Description: When averages of different experimental determinations of the same quantity are computed, each with statistical and systematic error components, then frequently the statistical and systematic components of the combined error are quoted explicitly. These are important pieces of information since statistical errors scale differently and often more favorably with the sample size than most systematical or theoretical errors. In this communication we describe a transparent procedure by which the statistical and systematic error components of the combination uncertainty can be obtained. We develop a general method and derive a general formula for the case of Gaussian errors with or without correlations. The method can easily be applied to other error distributions, as well. For the case of two measurements, we also define disparity and misalignment angles, and discuss their relation to the combination weight factors.

Description: In this work, we have studied the accretion of the \((n+2)\) -dimensional charged BTZ black hole (BH). The critical point and square speed of sound have been obtained. The mass of the BTZ BH has been calculated and we have observed that the mass of the BTZ BH is related with the square root of the energy density of the dark energy which accretes onto the BH in our accelerating FRW universe. We have assumed modified Chaplygin gas (MCG) as a candidate of dark energy which accretes onto the BH and we have found the expression of BTZ BH mass. Since in our solution of MCG, this model generates only quintessence dark energy (not phantom) and so BTZ BH mass increases during the whole evolution of the accelerating universe. Next we have assumed five kinds of parametrizations of well-known dark-energy models. These models generate both quintessence and phantom scenarios i.e., phantom crossing models. So if these dark energies accrete onto the BTZ BH, then in the quintessence stage, the BH mass increases up to a certain value (finite value) and then decreases to a certain finite value for the phantom stage during the whole evolution of the universe. We have shown these results graphically.

Description: We consider lepton-flavour violating decays of the top quark, mediated by 4-fermion operators. We compile constraints on a complete set of SU(3)  \(\times \)  U(1)-invariant operators, arising from their loop contributions to rare decays and from HERA’s single-top search. The bounds on e – \(\mu \) flavour change are more restrictive than on \(\ell \) – \(\tau \) ; nonetheless the top could decay to a jet \({+} e \bar{\mu }\) with a branching ratio of order \(10^{-3}\) . We estimate that the currently available LHC data (20 fb \(^{-1}\) at 8 TeV) could be sensitive to \(BR(t \rightarrow e \bar{\mu }\) + jet) \( {\sim } 6\times 10^{-5}\) , and we extrapolate that 100 fb \(^{-1}\) at 13 TeV could reach a sensitivity of \({\sim } 1 \times 10^{-5}\) .

Description: We carry out ADM splitting in the Lagrangian formulation and establish a procedure in which (almost) all of the unphysical components of the metric are removed by using the 4D diffeomorphism and the measure-zero 3D symmetry. The procedure introduces a constraint that corresponds to the Hamiltonian constraint of the Hamiltonian formulation, and its solution implies that the 4D dynamics admits an effective description through 3D hypersurface physics. As far as we can see, our procedure implies potential renormalizability of the ADM formulation of 4D Einstein gravity for which a complete gauge-fixing in the ADM formulation and hypersurface foliation of geometry are the key elements. If true, this implies that the alleged unrenormalizability of 4D Einstein gravity may be due to the presence of the unphysical fields. The procedure can straightforwardly be applied to quantization around a flat background; the Schwarzschild case seems more subtle. We discuss a potential limitation of the procedure when applying it to explicit time-dependent backgrounds.

Description: A well-established phenomenon in general relativity is the dragging of inertial frames by a spinning object. In particular, due to the dragging of inertial frames by a ring orbiting a central black hole, the angular velocity \(\Omega ^{\text {BH-ring}}_{\text {H}}\) of the black-hole horizon in the composed black-hole–ring system is no longer related to the black-hole angular momentum \(J_{\text {H}}\) by the simple Kerr-like (vacuum) relation \(\Omega ^{\text {Kerr}}_{\text {H}}(J_{\text {H}})=J_{\text {H}}/2M^2R_{\text {H}}\) (here M and \(R_{\text {H}}\) are the mass and horizon-radius of the black hole, respectively). Will has performed a perturbative treatment of the composed black-hole–ring system in the regime of slowly rotating black holes and found the explicit relation \(\Omega ^{\text {BH-ring}}_{\text {H}}(J_{\text {H}}=0,J_{\text {R}},R)=2J_{\text {R}}/R^3\) for the angular velocity of a central black hole with zero angular momentum, where \(J_{\text {R}}\) and R are respectively the angular momentum of the orbiting ring and its proper circumferential radius. Analyzing a sequence of black-hole–ring configurations with adiabatically varying (decreasing) circumferential radii, we show that the expression found by Will for \(\Omega ^{\text {BH-ring}}_{\text {H}}(J_{\text {H}}=0,J_{\text {R}},R)\) implies a smooth transition of the central black-hole angular velocity from its asymptotic near-horizon value \(\Omega ^{\text {BH-ring}}_{\text {H}}(J_{\text {H}}=0,J_{\text {R}},R\rightarrow R^{+}_{\text {H}})\rightarrow 2J_{\text {R}}/R^3_{\text {H}}\) (that is, just before the assimilation of the ring by the central black hole), to its final Kerr (vacuum) value \(\Omega ^{\text {Kerr}}_{\text {H}}(J^{\text {new}}_{\text {H}})= J^{\text {new}}_{\text {H}}/2{M^{\text {new}}}^2R^{\text {new}}_{\text {H}}\) [that is, after the adiabatic assimilation of the ring by the central black hole. Here \(J^{\text {new}}_{\text {H}}=J_{\text {R}}\) , \(M^{\text {new}}\) , and \(R^{\text {new}}_{\text {H}}\) are the new parameters of the resulting Kerr (vacuum) black hole after it assimilated the orbiting ring]. We use this important observation in order to generalize the result of Will to the regime of black-hole–ring configurations in which the central black holes possess non-zero angular momenta. In particular, it is shown that the continuity argument (namely, the characteristic smooth evolution of the black-hole angular velocity during an adiabatic assimilation process of the ring into the central black hole) yields a concrete prediction for the angular-velocity/angular-momentum asymptotic functional relation \(\Omega ^{\text {BH-ring}}_{\text {H}}=\Omega ^{\text {BH-ring}}_{\text {H}}(J_{\text {H}},J_{\text {R}},R\rightarrow R^{+}_{\text {H}})\) of generic (that is, with \(J_{\text {H}}\ne 0\) ) black-hole–ring configurations. Remarkably, we find the simple universal relation \(\Delta \Omega _{\text {H}}\equiv \Omega ^{\text {BH-ring}}_{\text {H}}(J_{\text {H}},J_{\text {R}},R\rightarrow R^{+}_{\text {H}})-\Omega ^{\text {Kerr}}_{\text {H}}(J_{\text {H}})={{J_{\text {R}}}/{4M^3}}\) for the asymptotic deviation of the black-hole angular velocity in the composed black-hole–ring system from the corresponding angular velocity of the unperturbed (vacuum) Kerr black hole with the same angular momentum.

Description: As an extension of previous works on classical tests of Kaluza–Klein (KK) gravity and as an attempt to find more stringent constraints on this theory, its effects on physical experiments and astronomical observations conducted in the Solar System are studied. We investigate the gravitational time delay at inferior conjunction caused by KK gravity, and use new Solar System ephemerides and the observation of Cassini to strengthen constraints on KK gravity by up to two orders of magnitude. These improved upper bounds mean that the fifth-dimensional space in the soliton case is a very flat extra dimension in the Solar System, even in the vicinity of the Sun.

Description: The normalized differential cross section for top quark pair ( \({\mathrm{t}}\overline{{\mathrm{t}}}\) ) production is measured in pp collisions at a centre-of-mass energy of 8 \(\,\text {TeV}\) at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7 \(\,\text {fb}^{-1}\) . The measurements are performed in the lepton \(+\) jets ( \(\mathrm {e}/\mu \) \(+\) jets) and in the dilepton ( \(\mathrm {e}^+\mathrm {e}^-\) , \(\mu ^+ \mu ^- \) , and \(\mathrm {e}^\pm \mu ^{\mp }\) ) decay channels. The \({\mathrm{t}}\overline{{\mathrm{t}}}\) cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the \({\mathrm{t}}\overline{{\mathrm{t}}}\) system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions.

Description: Recently we have shown that for \(2+1\) -dimensional thin-shell wormholes a non-circular throat may lead to a physical wormhole in the sense that the energy conditions are satisfied. By the same token, herein we consider an angular dependent throat geometry embedded in a \(2+1\) -dimensional flat spacetime in polar coordinates. It is shown that, remarkably, a generic, natural example of the throat geometry is provided by a hypocycloid. That is, two flat \(2+1\) dimensions are glued together along a hypocycloid. The energy required in each hypocycloid increases with the frequency of the roller circle inside the large one.