LSND and MiniBooNE as guideposts to understanding the muon $g-2$ results and the CDF II $W$ mass measurement

Abstract

In recent times, several experiments have observed results that are in significant conflict with the predictions of the Standard Model (SM). Two neutrino experiments, LSND and MiniBooNE (MB) have reported electron-like signal excesses above backgrounds. Both the Brookhaven and the Fermilab muon $g-2$ collaborations have measured values of this parameter which, while consistent with each other, are in conflict with the SM. Recently, the CDF II collaboration has reported a precision measurement of the $W$-boson mass that is in strong conflict with the SM prediction. It is worthwhile to seek new physics which may underly all four anomalies. In such a quest, the neutrino experiments could play a crucial role, because once a common solution to these anomalies is sought, LSND and MB, due to their highly restrictive requirements and observed final states, help to greatly narrow the multiplicity of new physics possibilities that are otherwise open to the $W$ mass and muon $g-2$ discrepancies. Pursuant to this, earlier work has shown that LSND, MB and the muon $g-2$ results can be understood in the context of a scalar extension of the SM which incorporates a second Higgs doublet and a dark sector singlet. We show that the same model leads to a contribution to the $W$ mass which is consistent with the recent CDF II measurement. While the LSND, MB fits and the muon $g-2$ results help determine the masses of the light scalars in the model, the calculation of the oblique parameters $S$ and $T$ determines the allowed mass ranges of the heavier pseudoscalar and the charged Higgs bosons as well as the effective Weinberg angle and its new range.