Neutral-current neutrino-nucleus scattering within QRPA models

Abstract

Recently a new formalism to describe chargedcurrent (CC) neutrino-nucleus reactions has been developed (Krmpoti´c et al., Phys Rev C 71:044319, 2005). Here, we have extended this model to describe neutrino-nucleus reactions via neutral-current (NC). As the weak interaction observables showed to be very sensitive to the structure of nuclear states, the use of microscopic nuclear structure models in a consistent theoretical framework are therefore essential for a quantitative description of neutrino-nucleus reactions. In previous calculations, we described the nuclearpart of these charge-exchange reactions within the Projected pn-QRPA (PQRPA) and usual pn-QRPA. In this work, we implemented the charge-conserving QRPA (ccQRPA), taking into account the proton-proton, neutron-neutron and proton-neutron pairing correlations. We evaluated inelasticneutrino-nucleus cross sections for 12C and 40Ar comparing to other nuclear models in the literature. The cross sections for 12C are folded by Michel spectrum, where a good agreement between our result and the experimental data for 12C(ν, ν)12C∗ [1+, 1; 15.1MeV] (Drexlin et al., in Proceedings of the NeutrinoWorkshop, Heidelberg, 1987. Springer-Verlag, Berlin, 1987; Drexlin et al., Phys Lett B 267:321, 1991; Zeitnitz, Prog Part Nucl Phys 32:351, 1994; Kleinfellner et al., in Proceedings of theXIII International Conference on Particles and Nuclei, Perugia, Italy, 1993) is achieved. For 40Ar, the competition between Gamow-Teller (GT) and dipole transitions showed to be an important ingredient to understand these reactions, that appears as the backgrounds to neutrinos appearance in the far detector in DUNE experiment.