No Arabic abstract
We study charged-current neutrino cross sections on neutronrich nuclei in the mass $Asim60$ region. Special attention is paid to environmental effects, i.e. finite temperature and density, on the cross sections. As these effects are largest for small neutrino energies, it is sufficient to study only the Gamow-Teller (GT) contributions to the cross sections. The relevant GT strength distributions are derived from large-scale shell model calculations. We find that the low-energy cross sections are enhanced at finite temperatures. However, for $( u_e,e^-)$ reactions Pauli blocking of the electrons in the final state makes the cross sections for low-energy neutrinos much smaller than for the competing inelastic scattering on electrons at moderate and large densities. Absorption cross sections for low-energy antineutrinos are strongly enhanced at finite temperatures.
We present neutrino capture cross sections on 13C at supernova neutrino energies, up to 50 MeV. For both charged-current and neutral-current reactions partial cross sections are calculated using statistical Hauser-Feschbach method. Coherent elastic neutrino scattering cross section for a 13C target is also provided.
The inclusive neutrino/antineutrino-induced charged and neutral current reaction cross-sections in $^{12}C$, $^{16}O$, $^{40}Ar$, $^{56}Fe$ and $^{208}Pb$ in the energy region of supernova neutrinos/antineutrinos are studied. The calculations are performed in the local density approximation (LDA) taking into account the effects due to Pauli blocking, Fermi motion and the renormalization of weak transition strengths in the nuclear medium. The effect of Coulomb distortion of the lepton produced in the charged current reactions has also been included. The numerical results for the energy dependence of the cross-section $sigma(E)$ as well as the flux averaged cross-section and event rates for the charged lepton production in the case of some supernova neutrino/antineutrino fluxes recently discussed in the literature have been presented. We have also given the flux-averaged angular and energy distributions of the charged leptons corresponding to these fluxes.
We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $Delta $- dominance model taking into account the renormalization of $Delta$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.
The effects of the theoretical uncertainties in the description of neutrino-nucleus cross sections for supernova neutrino energies are investigated.
Merits and faults of the effective theory Random Phase Approximations are discussed in the perspective of its use in the prediction of neutrino-nucleus cross sections.