Probing light mediators in the radiative emission of neutrino pair

Abstract

AbstractWe propose a new possibility of using the coherently enhanced neutrino pair emission to probe light-mediator interactions between electron and neutrinos. With typical momentum transfer at the atomic $$\mathcal O(1$$ O ( 1  eV) scale, this process is extremely sensitive for the mediator mass range $$\mathcal O(10^{-3} \sim 10^4$$ O ( 10 - 3 ∼ 10 4 ) eV. The sensitivity on the product of couplings with electron ($$g^e$$ g e or $$y^e$$ y e ) and neutrinos ($$g^\nu $$ g ν or $$y^\nu $$ y ν ) can touch down to $$|y^e y^\nu | < 10^{-9} \sim 10^{-19}$$ | y e y ν | < 10 - 9 ∼ 10 - 19 for a scalar mediator and $$|g^e g^\nu | < 10^{-15} \sim 10^{-26}$$ | g e g ν | < 10 - 15 ∼ 10 - 26 for a vector one, with orders of improvement from the existing constraints.