Constraining nonstandard neutrino interactions with electrons

Abstract

We update the phenomenological constraints of the nonstandard neutrino interactions (NSNI) with electrons including in the analysis, for the first time, data from LAMPF, Krasnoyarsk, and the latest Texono observations. We assume that NSNI modify the cross section of elastic scattering of (anti)neutrinos off electrons, using reactor and accelerator data, and the cross section of the electron-positron annihilation, using the four LEP experiments, in particular, new data from DELPHI. We find more restrictive allowed regions for the NSNI parameters: $\ensuremath{-}0.11l{\ensuremath{\epsilon}}_{ee}^{eR}l0.05$ and $\ensuremath{-}0.02l{\ensuremath{\epsilon}}_{ee}^{eL}l0.09$ (90% C.L.). We also recalculate the parameters of tauonic flavor obtaining $\ensuremath{-}0.35l{\ensuremath{\epsilon}}_{\ensuremath{\tau}\ensuremath{\tau}}^{eR}l0.50$ and $\ensuremath{-}0.51l{\ensuremath{\epsilon}}_{\ensuremath{\tau}\ensuremath{\tau}}^{eL}l0.34$ (90% C.L.). Although more severe than the limits already present in the literature, our results indicate that NSNI are allowed by the present data as a subleading effect, and the standard electroweak model continues consistent with the experimental panorama at 90% C.L. Further improvement on this picture will deserve a lot of engagement of upcoming experiments.