Vector leptoquark resolution of $R_K$ and $R_{D^{(*)}}$ puzzles

TL;DR

This paper proposes a vector leptoquark model to simultaneously explain anomalies in B meson decays, providing specific predictions and constraints from various decay processes and flavor universality tests.

Contribution

The paper introduces a single vector leptoquark triplet model that accounts for multiple B decay anomalies and derives experimental constraints and predictions.

Findings

The model can explain $R_{D^{(*)}}$, $R_K$, and $P_5'$ anomalies.

Predicts similar values for $R_{K^*}$ and $R_K$ ratios.

Suggests observable effects in $t o b au u$ and $B o K^{(*)} ar u u$ decays.

Abstract

We propose that three recent anomalies in $B$ meson decays, $R_{D^{(*)}}$, $R_K$, and $P_5'$, might be explained by a single vector leptoquark weak triplet state. The constraints on the parameter space are obtained by considering $t \to b \tau^+ \nu$ data, lepton flavor universality tests in the kaon sector, bounds on $B \to K^{(*)} \bar \nu \nu$, bound on the lepton flavor violating decay $B \to K \mu \tau$, and measurements of $b \to c \mu^- \bar\nu$ decays. The presence of such vector leptoquark could be exposed in precise measurements of $t \to b \tau \nu$ and $B \to K^{(*)} \bar \nu \nu$ decays. The model also predicts approximate equality of lepton flavor universality ratios $R_{K^*}$, $R_{K}$, and suppressed branching fraction of $B_s \to \mu^+ \mu^-$.