Improved limit on electron neutrino charge radius through a new evaluation of the weak mixing angle

Abstract

We have obtained a new limit on the electron neutrino effective charge radius from a new evaluation of the weak mixing angle by a combined fit of all electron-(anti)neutrino electron elastic scattering measurements. Weak mixing angle is found to be sin 2 θ W = 0.259±0.025 in the low energy regime below 100 MeV. The electron neutrino charge radius squared is bounded to be in the range −0.13 × 10 −32 cm 2 < r 2 νe < 3.32 × 10 −32 cm 2 at 90% C.L. Both results improve previously published analyses. We also discuss perspectives of future experiments to improve these constraints.

Probing nonstandard interactions with reactor neutrinos

“…This result improves previous bounds [15,4]. We remind that only statistical error for the TEX-ONO measurement [6] was taken into account.…”

“…All relevant references can be found in Ref. [4] and in the recent review [11]. A more general interpretation of the experimental results which we adopt here is that they are limits on cer- tain nonstandard contributions to neutrino scattering.…”

“…All references to the experimental data used in the analysis are given in Ref. [4], except the recent talk by the TEXONO Collaboration at the ICHEP 2008 Conference [6]. The measurement presented by TEXONO Collaboration was obtained using CsI(Tl) detector at Kuo-Sheng Nuclear Power Plant in Taiwan [6] sin 2 θ W = 0.24 ± 0.05 (stat) .…”

“…[4] due to the inclusion of recent TEXONO 2008 measurement with CsI(Tl) detector [6]. It is not competitive with the current best measurements at low energies of the atomic parity violation [13] and of the Møller scattering by SLAC E158 [14], both experiments have a precision better than 0.5%.…”

“…Here we focus on the NSI effects in neutrino detection at low energies [1][2][3][4][5]. We will present the limits on the weak mixing angle, sin 2 θ W , and on the electron neutrino effective charge radius, r 2 νe , obtained from the combined analysis of all available low energy (anti)neutrino-electron elastic scattering experiments including recent ν-e cross section measurement by TEXONO [6].…”