Confusing sterile neutrinos with deviation from tribimaximal mixing at neutrino telescopes

Ram Lal Awasthi and Sandhya Choubey

Phys. Rev. D 76, 113002 – Published 17 December 2007

Abstract

We expound on the impact of extra sterile species on the ultra high energy neutrino fluxes in neutrino telescopes. We use three types of well-known flux ratios and compare the values of these flux ratios in the presence of sterile neutrinos, with those predicted by deviation from the tribimaximal mixing scheme. We show that in the upcoming neutrino telescopes, it is easy to confuse the signature of sterile neutrinos with that of the deviation from tribimaximal mixing. We also show that if the measured flux ratios acquire a value well outside the range predicted by the standard scenario with three active neutrinos only, it might be possible to tell the presence of extra sterile neutrinos by observing ultra high energy neutrinos in future neutrino telescopes.

Received 24 June 2007

DOI:https://doi.org/10.1103/PhysRevD.76.113002

Authors & Affiliations

Ram Lal Awasthi^* and Sandhya Choubey^†

Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019, India

^*ramlal@mri.ernet.in
^†sandhya@mri.ernet.in

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Issue

Vol. 76, Iss. 11 — 1 December 2007

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Images

Figure 1
The flux ratios $R_{e}$ , $R_{μ}$ , and $R_{τ}$ versus ${sin }^{2} θ_{23}$ , for three active neutrinos. The light bands correspond to allowed ranges of the flux ratios corresponding to all currently $3 σ$ allowed values of ${sin }^{2} θ_{12}$ and ${sin }^{2} θ_{13}$ and where $\cos δ$ is kept fixed as 1. The dark bands show the corresponding allowed values where ${sin }^{2} θ_{12}$ and ${sin }^{2} θ_{13}$ vary in their current $3 σ$ allowed ranges and $\cos δ$ is allowed to vary between $- 1$ and 1. The upper (lower) boundaries of the light and dark bands almost coincide with each other in the left (middle and right) panels.Reuse & Permissions
Figure 2
The flux ratios $R_{e}$ , $R_{μ}$ , and $R_{τ}$ versus ${sin }^{2} θ_{13}$ , for three active neutrinos and when ${sin }^{2} θ_{12} = 1 / 3$ , ${sin }^{2} θ_{23} = 1 / 2$ . The dotted lines correspond to $\cos δ = 1$ , the solid lines to $\cos δ = 0$ , and the dashed lines to $\cos δ = - 1$ .Reuse & Permissions
Figure 3
Contour bands of the flux ratios $R_{e}$ , $R_{μ}$ , and $R_{τ}$ in the ${sin }^{2} θ_{23} - {sin }^{2} θ_{34}$ plane. The $R_{e}$ bands increase from 0.44 (lower right-hand corner) to 1.1 (upper left-hand corner) in steps of 0.066, the $R_{μ}$ bands increase from 0.49 (lower left-hand corner) to 1.18 (upper right-hand corner) in steps of 0.069, while the $R_{τ}$ bands increase from 0.00 (bottom) to 0.51 (up) in steps of 0.051. We have kept $θ_{14} = 0 = θ_{24}$ and all other mixing angles at their TBM mixing values.Reuse & Permissions
Figure 4
Panel (a) shows the contours in the ${sin }^{2} 2 θ_{23} - {sin }^{2} θ_{34}$ plane which satisfy the corresponding condition given by Eq. (51). Each point on a given line gives the value of ${sin }^{2} θ_{34}$ which along with TBM in active part would give the same flux ratio as three active neutrinos but with that value for ${sin }^{2} 2 θ_{23}$ . Panel (b) gives the corresponding contours in the ${sin }^{2} 2 θ_{23} - {sin }^{2} θ_{24}$ plane, showing the condition Eq. (55).Reuse & Permissions
Figure 5
Contour bands of the flux ratios $R_{e}$ , $R_{μ}$ , and $R_{τ}$ in the ${sin }^{2} θ_{23} - {sin }^{2} θ_{24}$ plane. The $R_{e}$ bands increase from 0.436 (lower right-hand corner) to 0.610 (upper left-hand corner) in steps of 0.017, the $R_{μ}$ bands increase from 0.447 (upper left-hand side) to 0.559 (lower right-hand corner) in steps of 0.011, while the $R_{τ}$ bands increase from 0.445 (left-hand side) to 0.526 (right-hand side) in steps of 0.008. We have kept $θ_{14} = 0 = θ_{34}$ and all other mixing angles at their TBM mixing values.Reuse & Permissions
Figure 6
Three-dimensional plots showing the flux ratios $R_{e}$ (left panel), $R_{μ}$ (middle panel), and $R_{τ}$ (right panel), as a function of ${sin }^{2} θ_{24}$ and ${sin }^{2} θ_{34}$ . The angles $θ_{13} = 0 = θ_{14}$ , ${sin }^{2} θ_{12} = 1 / 3$ , and ${sin }^{2} θ_{23} = 0.5$ .Reuse & Permissions

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