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Digitale Medien

OnD→ππ and $$K\bar K$$ decays (1992)

Czarnecki, Andrzej ; Kamal, A. N. ; Xu, Qiping

Springer

The European physical journal 54 (1992), S. 411-417

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We have analysed the recent data onD→ππ and $$K\bar K$$ decays from ARGUS, CLEO and E691. (i) We find that Bauer, Stech and Wirbel (BSW) model does fairly well in explaining all data if we assume that final state interactions simply rotate the amplitudes in the complex plane. However, to get a good fit one needs to raiseD→K transition amplitudes by (5–10)% over the BSW values and lowerD→π amplitudes by a similar amount. (ii) We show that all the data can also be understood in a coupled channel inelastic model. (iii) We also find that the Isgur, Scora, Grinstein and Wise (ISGW) model-form factors, if extrapolated to small momentum transfers (t) by a single pole formula, yield branching ratios too small in comparison to data. We propose an alternate scheme to interpolate between BSW form factors att=0 and ISGW form factors att=t max.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01559458

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2

Digitale Medien

Pion form factors and phase shifts (1969)

Shymko, R. M. ; Kamal, A. N.

Springer

The European physical journal 228 (1969), S. 120-128

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ISSN: 1434-601X

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract The problem of determining theP-waveπ-π phase-shifts given the modulus of the electromagnetic form-factor in the time-like momentum transfer region has been discussed. The problem ofK 1 0 −K 2 0 mass difference has been discussed with emphasis on the scalar form-factor rather than models ofπ -π scattering.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01397533

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3

Digitale Medien

On an inverse method in one dimension (1983)

Asthana, Praveer ; Kamal, A. N.

Springer

The European physical journal 19 (1983), S. 37-52

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract Given a sequence of bound-state energies, the inverse Gel'fand-Levitan theory for the one-dimensional Schrödinger equation enables us to uniquely construct a symmetric reflectionless potential which supports those bound states. We test the reliability of this technique by applying it to some known symmetric potentials (confining and non-confining) in one dimension. We also study the systematics under which the method may be reliable.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01572334

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4

Digitale Medien

Model for γγ→VV reactions near threshold (1991)

Kamal, A. N. ; Sinha, R.

Springer

Few body systems 10 (1991), S. 159-170

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ISSN: 1432-5411

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We propose a Veneziano-like model for γγ→VV reactions near threshold involving exchanges of 0− trajectories int- andu-channels. The model is applied to γγ→ωω, ϕϕ, ρϕ, ρω and ωϕ processes. The model in its simplest form cannot account for the disparities in the cross sections for $$\gamma \gamma \to {\rm K}^{ * 0} \bar K^{*0}$$ andK *+ K *− and for γγ→ρ0ρ0 and ρ+ρ−. Further refinements of the model are suggested.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01076292

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5

Digitale Medien

Radiative weak decay of baryons within the Bethe-Salpeter formalism (1991)

Asthana, P. ; Kamal, A. N.

Springer

Few body systems 11 (1991), S. 1-24

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ISSN: 1432-5411

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract The Nishijima-Mandelstam formula for the transition amplitude of radiative weak decay of baryons is derived within the Bethe-Salpeter formalism in a manner parallel to the Lehmann-Synanzik-Zimmermann reduction procedure. Feynaman rules for bound quarks are discussed. Employing a Gaussian Bethe-Salpeter amplitude for baryons used by other authors, the transition amplitude for ∑+ →pγ has been calculated. Due to the use of a phenomenological Bethe-Salpeter wave function, the resulting amplitude turns out to be non-gauge invariant. Gauge invariance is imposed by hand and the asymmetry parameter calculated. Normalization of the decay amplitude and calculation of the absolute rate is not attempted. Two serious problems remain in this calculation: First, the lack of gauge invariance, and, second, the calculated amplitudes turn out to be complex.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01075710

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6

Digitale Medien

Hadronic interaction corrections to two bodyD 0-decays (1981)

Kamal, A. N. ; Cooper, E. D.

Springer

The European physical journal 8 (1981), S. 67-75

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We carry out final state hadronic interaction corrections to two body decays ofD 0-meson. We demonstrate that the ratio $${{\Gamma \left( {D^0 \to K^ - \pi ^ + } \right)} \mathord{\left/ {\vphantom {{\Gamma \left( {D^0 \to K^ - \pi ^ + } \right)} {\Gamma \left( {D^0 \to \bar K^0 \pi ^0 } \right)}}} \right. \kern-\nulldelimiterspace} {\Gamma \left( {D^0 \to \bar K^0 \pi ^0 } \right)}}$$ can be very different from the free quark and the hard gluon corrected schemes. We also discuss Γ(D 0→K + K −)/Γ(D 0→π + π −) treating the ππ and theK $$\bar K$$ systems as coupled channels.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01429834

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7

Digitale Medien

A single quark model for single pion photoproduction at threshold (1984)

Araki, M. ; Kamal, A. N.

Springer

The European physical journal 25 (1984), S. 187-190

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract Single pion photoproduction is studied in a single quark model in which a quark absorbs the photon and then emits the pion, propagating as a quark between the two interactions. Two different chiral bag models are used which allow for the coupling of the quarks to the pion. Surprisingly, the single quark model reproduces the results of phenomenological models and agrees with the experimental amplitudes to within 30% at threshold.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01557478

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8

Digitale Medien

Cabibbo-angle-favored decays:D→SP (1987)

Hussain, F. ; Kamal, A. N. ; Sinha, S. N.

Springer

The European physical journal 36 (1987), S. 199-207

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We have studiedD→K 0 * π andD→Ka 0 decays in the factorization approximation. The spectator model leads to a color-suppression of $$D^0 \to \bar K_0^{*0} \pi ^0 $$ . However, due to the smallness off a 0, a similar suppression does not occur for $$D^0 \to \bar K^0 a_0^0 $$ . We show that the inclusion of annihilation contribution can lift the color-suppression of $$D^0 \to \bar K_0^{*0} \pi ^0 $$ . We also include final state interactions in a dynamical model whereK (1830) pole in the direct channel dominates the annihilation process.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01579135

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9

Digitale Medien

An analysis of Cabibbo-favored two-body decays of charmed mesons withη orη′ in the final state (1995)

Verma, R. C. ; Kamal, A. N. ; Khanna, M. P.

Springer

The European physical journal 65 (1995), S. 255-262

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We have carried out a study of Cabbibbo-favored two-body decays ofD 0 andD s + involving η and η′ in the final state, $$D^0 \to (\eta ,\eta ')\bar K^0 , D^0 \to (\eta ,\eta ')\bar K*^0 $$ andD s + →(η,η′)π +,D s + →(η,η′)ρ +. We have introduced an annihilation term wherever admissible, and investigated its size if it were to bridge the gap between theory and experiment in each case. We have also related the semileptonic rates forD s + →(η,η′)e + v to those of the hadronic rates forD s + →(η,η′)π + and unveiled a puzzle. We offer a possible solution.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01571881

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