Experimental bound on the charge radius of the electron neutrino

Abstract

A limit on the electron-neutrino charge radius Irl is derived from a measurement of the weakneutral-current vector coupling constant gv obtained in electron-neutrino electron elastic scattering. The 90%-confidence interval for gv is -0.177 < gv < 0.187, which for sin2ew -0.227 implies that the v, mean-square charge radius is in the range -2.74x < ( r 2 ) < 4.88X cm2, or simply Irl < 2.2x 10-l6 cm. This is the first experimental bound on the v, charge radius, and is the same order of magnitude as bounds for v, structure.