The Gallium Anomaly

Parallel talk presented at the XXI International Workshop on Neutrino Telescopes - Padova 29 September - 3 October 2025

(https://agenda.infn.it/event/44606/)

Abstract:

The Standard Model (SM) has long provided a remarkably successful framework for describing fundamental interactions. However, persistent anomalies in the neutrino sector, most notably the long-standing Gallium Anomaly, suggest potential deviations that warrant further investigation. In this talk, I address both the reinterpretation of the neutrino-gallium cross section and precision constraints from neutrino-electron scattering. First, I discuss a revised calculation of the neutrino–gallium charged-current cross section [1], incorporating updated inputs and refined modeling of the transition dynamics. Our results indicate a systematic shift in the predicted interaction rate, with intriguing implications for the calibration of solar neutrino detectors and for the possible existence of sterile neutrinos.

In parallel, I present a global fit of neutrino-electron scattering (νES) data [2] from TEXONO, LAMPF, LSND, BNL-E734, and CHARM-II, complemented by solar neutrino measurements from direct dark matter detection experiments such as LZ, XENONnT, and PandaX. These allow us to extract robust constraints on the vector and axial-vector neutrino-electron neutral current couplings, while explicitly accounting for flavor-dependent effects and momentum-transfer corrections.
The analysis reveals two viable solutions: one in close agreement with the SM prediction, and a degenerate alternative currently favored by the data. I emphasize the crucial role of radiative corrections and energy dependence in reducing theoretical uncertainties. Looking ahead, I show that next-generation dark matter detectors will have the sensitivity needed to resolve these degeneracies and deliver unprecedented tests of electroweak theory in the neutrino sector.