Neutrino–nucleus reactions via neutral and charged currents by the quasi-particle random phase approximation (QRPA)

Abstract

We developed the quasi-particle random phase approximation (QRPA) for the neutrino scattering off even-even nuclei via neutral current (NC) and charged current (CC). The QRPA has been successfully applied for the β and ββ decay of relevant nuclei. To describe neutrino scattering, general multipole transitions by weak interactions with a finite momentum transfer are calculated for NC and CC reaction with detailed formalism. Since we consider neutron-proton (np) pairing as well as neutron-neutron (nn) and proton-proton (pp) pairing correlations, the nn + pp QRPA and np QRPA are combined in a framework, which enables to describe both NC and CC reactions in a consistent way. Numerical results for ν− 12 C, − 56 Fe and − 56 Ni reactions are shown to comply with other theoretical calculations and reproduce well available experimental data.

Neutrino induced reactions forν-process nucleosynthesis of92Nb and98Tc

“…Previous studies have concluded that contributions from the CC reactions are generally larger than those of NC reactions for heavy nuclei [2,[15][16][17].…”

“…Such a small effect in light nuclei is easily understood because the energy gaps between the neutron and proton energy spaces are too large to be effective. However, in intermediate-mass nuclei, such as 56 Fe and 56 Ni, the np pairing effect accounts for 20 ∼ 30 % of the total cross section [16]. Therefore, for the heavy nuclei of interest in the present work, np pairing should be taken into account.…”

“…The QRPA formalism employed here for the ν(ν)-nucleus (ν(ν) − A) reactions has been detailed in our previous papers [15][16][17]. We have applied this formalism to successfully describe the relevant ν-induced reaction data for 12 C [15], 56 Fe, 56 Ni [16], 138 La, and 180 Ta [17], as well as β, 2ν2β and 0ν2β decays [24].…”

“…We have applied this formalism to successfully describe the relevant ν-induced reaction data for 12 C [15], 56 Fe, 56 Ni [16], 138 La, and 180 Ta [17], as well as β, 2ν2β and 0ν2β decays [24]. In particular, double beta (2β) decay is well known to be sensitive to the nuclear structure and has more data than the ν-induced reaction data.…”

“…β ± decay and the ν− 12 C reaction [15,16]. Such a small effect in light nuclei is easily understood because the energy gaps between the neutron and proton energy spaces are too large to be effective.…”