Confronting lepton flavor universality violation in B decays with high-$p_T$ tau lepton searches at LHC

TL;DR

This paper investigates how high-energy tau lepton searches at the LHC can test new physics explanations for lepton flavor universality violation observed in B meson decays, setting limits on various models.

Contribution

It establishes a connection between LFU violation signals in B decays and high-$p_T$ tau searches at the LHC, providing constraints on several new physics models.

Findings

$ au^+ au^-$ searches strongly constrain new physics explanations of LFU violation.

Existing LHC data set stringent limits on models with vector resonances, leptoquarks, and extended Higgs sectors.

Future analyses could further test or exclude these new physics scenarios.

Abstract

We confront the indications of lepton flavor universality (LFU) violation observed in semi-tauonic $B$ meson decays with new physics (NP) searches using high $p_T$ tau leptons at the LHC. Using effective field theory arguments we correlate possible non-standard contributions to semi-tauonic charged currents with the $\tau^+ \tau^-$ signature at high energy hadron colliders. Several representative standard model extensions put forward to explain the anomaly are examined in detail: (i) weak triplet of color-neutral vector resonances, (ii) second Higgs doublet and (iii) scalar or (iv) vector leptoquark. We find that, in general, $\tau^+ \tau^-$ searches pose a serious challenge to NP explanations of the LFU anomaly. Recasting existing 8 TeV and 13 TeV LHC analyses, stringent limits are set on all considered simplified models. Future projections of the $\tau^+ \tau^-$ constraints as well as caveats in interpreting them within more elaborate models are also discussed.