Constraining the solar neutrino survival probability curve by using Li6 , Li7 , C12 , O18 , F19 , and Ca42 nuclear targets

Abstract

Precise measurement of the survival probability ${P}_{ee}$ of solar electron neutrino (${\ensuremath{\nu}}_{e}$) as a function of its energy [${P}_{ee}({E}_{\ensuremath{\nu}e})$] is one of the key issues in neutrino physics. Current ${P}_{ee}$ data, due to their limited accuracy, still allow for nonstandard interactions (NSIs) to be alternatives to the standard one, which is based on the MSW-LMA prediction. In order to determine ${P}_{ee}$ values at several values of ${E}_{\ensuremath{\nu}e}$ with higher accuracy, we propose to use several target nuclei with different threshold energies for ${\ensuremath{\nu}}_{e}$ detection. We examined charged-current (CC) responses of various nuclei seeking the ones: (a) having large and concentrated Gamow-Teller (GT) transition strength in the low excitation-energy region, and (b) having appropriate and a variety of reaction $Q$ values, i.e., $\ensuremath{\approx}1$ to 17 MeV, in the (${\ensuremath{\nu}}_{e},{e}^{\ensuremath{-}}$) reaction. As a result, we found that systematic solar ${\ensuremath{\nu}}_{e}$ measurements with target nuclei $^{6}\mathrm{Li}$, $^{7}\mathrm{Li}$, $^{12}\mathrm{C}$, $^{18}\mathrm{O}$, $^{19}\mathrm{F}$, and $^{42}\mathrm{Ca}$ can put strong constraints on the ${P}_{ee}({E}_{\ensuremath{\nu}e})$ curve and thus on these NSI models. In addition, we notice that three of these nuclei, $^{6}\mathrm{Li}$, $^{7}\mathrm{Li}$, and $^{12}\mathrm{C}$, have large and concentrated neutral-current (NC) responses with detection threshold-energies of 3.56, 0.48, and 15.11 MeV, respectively. Note that the NC measurement is flavor independent. Thus, the measured results should represent the original strength of ${\ensuremath{\nu}}_{e}$ from the Sun.