Nuclear response to supernova neutrino spectra

Abstract

In current probes searching for rare event processes, appropriate nuclear targets are employed (in the COBRA double-beta decay detector the CdZnTe semiconductor is used). In this work the response of such detectors to various low-energy neutrino spectra is explored starting from state-by-state calculations of the neutrinonucleus reactions cross sections obtained by using the quasi particle random phase approximation (QRPA) based on realistic two-body residual interactions. As a concrete example, we examine the response of 64 Zn isotope to low energy supernova neutrinos.

Studying supernova neutrinos through nuclear structure calculations

“…3, except a slight quantitative difference between the curves of the interference term σ V A . For neutrino energies ε ν 5 − 8 MeV, the polar-vector contribution σ V dominates, while for large energies the axial-vector cross section σ A is approximately equal to the total cross section σ tot [4,5].…”

“…The calculational procedure of this work was carried out with the following steps. In the first step, the original results for the double differential cross section d 2 σ/dΩdǫ f [3,4], were obtained for both nuclear isotopes, 64,66 Zn. Figure 2, shows the double differential cross section as a function of the excitation energy ω of the nucleus and the scattering angle θ of the outgoing lepton, for 66 Zn.…”

“…where ℓ = e, µ, τ [4]. In the first stage, we determine the model parameters describing the nuclear structure of 64 Zn and 66 Zn as follows.…”

“…They have been determined so as the low-lying excitation spectrum of each isotope (ω 4 MeV) to be reproduced. In Tables 1 and 2, we tabulate the values of the parameters used for the construction of the nuclear states of the isotopes 64,66 Zn: the initial (ground) state, which has been constructed by the BCS method and the final excited states which have been constructed within the QRPA method [4,5].…”