The potential to probe solar neutrino physics with LiCl water solution

Abstract

Abstract A solar neutrino detector relying on the charged-current (CC) interaction of $$\nu _e$$ ν e on $$\mathrm{{}^{7}Li}$$ 7 Li is attractive. The total CC interaction cross-section weighted by the solar $$^8$$ 8 B electron neutrino spectrum is approximately 60 times that of the neutrino-electron elastic scattering process. The final state effective kinetic energy after the CC interaction on $$\mathrm{{}^{7}Li}$$ 7 Li directly reflects the neutrino energy, which stands in sharp contrast to the plateau structure of recoil electrons of the elastic scattering. The recent measurement of the optical properties of saturated LiCl water solution, especially the long attenuation length, has once again aroused our interest in LiCl. In this work, with new B(GT) experimental measurements, the CC cross-section on $$\mathrm{{}^{7}Li}$$ 7 Li is reevaluated to be $$3.759\times 10^{-42}~\textrm{cm}^2$$ 3.759 × 10 - 42 cm 2 . Given the high solubility of LiCl of 74.5 g/100 g water at 10 $$^\circ $$ ∘ C and the high natural abundance of 92.41% of $$\mathrm{{}^{7}Li}$$ 7 Li , a solar neutrino detection proposal is made. The detector with high concentration LiCl water solution has a comparable CC event rate of $$\nu _e$$ ν e on $$\mathrm{{}^{7}Li}$$ 7 Li with that of neutrino-electron elastic scattering. The contained $$\mathrm{{}^{35}Cl}$$ 35 Cl , $$\mathrm{{}^{6}Li}$$ 6 Li , and H also make a delayed-coincidence detection for $${{\bar{\nu }}}_e$$ ν ¯ e possible. The advantages of studying the upturn effect of solar neutrino oscillation, light sterile neutrinos, and Earth matter effect are investigated in detail. The sensitivities in discovering solar neutrino upturn and light sterile neutrinos are presented.