Solar neutrino probes of the muon anomalous magnetic moment in the gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$

Abstract

Models of gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ can provide a solution to the long-standing discrepancy between the theoretical prediction for the muon anomalous magnetic moment and its measured value. The extra contribution is due to a new light vector mediator, which also helps to alleviate an existing tension in the determination of the Hubble parameter. In this article, we explore ways to probe this solution via the scattering of solar neutrinos with electrons and nuclei in a range of experiments and considering high and low solar metallicity scenarios. In particular, we reevaluate Borexino constraints on neutrino-electron scattering, finding them to be more stringent than previously reported, and already excluding a part of the (g − 2)μ explanation with mediator masses smaller than 2 × 10−2 GeV. We then show that future direct dark matter detectors will be able to probe most of the remaining solution. Due to its large exposure, LUX-ZEPLIN will explore regions with mediator masses up to 5 × 10−2 GeV and DARWIN will be able to extend the search beyond 10−1 GeV, thereby covering most of the area compatible with (g − 2)μ. For completeness, we have also computed the constraints derived from the recent XENON1T electron recoil search and from the CENNS-10 LAr detector, showing that none of them excludes new areas of the parameter space. Should the excess in the muon anomalous magnetic moment be confirmed, our work suggests that direct detection experiments could provide crucial information with which to test the $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ solution, complementary to efforts in neutrino experiments and accelerators.

Constraints on light vector mediators through coherent elastic neutrino nucleus scattering data from COHERENT

“…Our results for the L µ −L τ Z model are more stringent than those obtained recently in ref. [84] by fitting the number of CEνNS events obtained by the COHERENT Collaboration from the fit of the data [17]. Since this is not a real fit of the COHERENT data, the result is questionable.…”

Global fits of axion-like particles to XENON1T and astrophysical data

“…Weakly-interacting relativistic bosons that are produced by the annihilation or decay of heavier dark particles have also been proposed to account for the data [9,54,56,57]. Alternatively, the anomaly might result from new neutrino-lepton or non-standard neutrino interactions mediated by a light scalar or a vector particle [3,13,14,45,[58][59][60][61][62]]. Yet more potential explanations include exotic radioactivity affecting hydrogen decays [25], fermionic DM with an electric dipole moment (EDM) sourced by an oscillating axion-like field [63], and the resurrection of the solar ALP explanation via the postulate of a "stellar basin" of gravitationally-bound axions in the Sun [64].…”

The physics potential of a reactor neutrino experiment with Skipper CCDs: measuring the weak mixing angle

“…erties [39][40][41][42][43][44][45][46][47][48][49], solar physics [50][51][52], light sterile neutrinos [53][54][55][56][57][58][59] and dark matter/dark sector models [60][61][62][63]. Nevertheless, the potential of Skipper CCDs near the core of a commercial nuclear reactor, despite very promising, is still largely unknown.…”