Neutrino-nucleus scattering offXe136

Abstract

Background: Theoretical estimates of the cross sections for the neutrino-nucleus scattering off relevant nuclei for supernova neutrinos are essential for many applications in neutrino physics and astrophysics. The double-$\ensuremath{\beta}$-decaying nucleus $^{136}\mathrm{Xe}$ nucleus is used by the EXO Collaboration in the search for neutrinoless double-$\ensuremath{\beta}$ decay. A ton-scale experiment based on $^{136}\mathrm{Xe}$ could also be used for studies of supernova neutrinos and/or solar neutrinos.Purpose: The purpose of the present work is, thus, to perform a study of the charged-current and neutral-current nuclear responses to supernova neutrinos for $^{136}\mathrm{Xe}$.Method: The cross sections are computed by using the well-established framework for studies of semileptonic processes in nuclei introduced by O'Connell, Donnelly, and Walecka [Phys. Rev. C 6, 719 (1972)]. The nuclear wave functions of the initial and the final nuclear states for the neutral-current neutrino-nucleus scattering in $^{136}\mathrm{Xe}$ are computed by using the quasiparticle random-phase approximation (QRPA). Similarly, the pnQRPA is adopted to construct the initial and final nuclear states which are relevant for the charged-current reactions. The nuclear responses to supernova neutrinos are subsequently computed by folding the cross sections with appropriate energy spectra for the incoming neutrinos.Results: We present results for the cross sections of the charged-current and neutral-current neutrino and antineutrino scatterings off $^{136}\mathrm{Xe}$. Nuclear responses to supernova neutrinos are also given. For the considered scenario for the neutrino mixing we have found that neutrino interactions with matter and so-called collective neutrino oscillations enhance significantly the neutrino and antineutrino flux-averaged cross sections.Conclusions: We have found that for the charged-current and neutral-current neutrino scatterings off $^{136}\mathrm{Xe}$ transitions mediated by the ${1}^{+}$ multipole are the most important ones. However, for the charged-current antineutrino channel ${0}^{+}$ and ${1}^{+}$ transitions are largely suppressed due to the large neutron excess. Transitions to ${1}^{\ensuremath{-}}$ and ${2}^{\ensuremath{-}}$ final nuclear states are thus relatively more important for the charged-current antineutrino scattering.