Leptoquark Option for $B$-meson Anomalies and Leptonic Signatures

Abstract

We entertain the option of scalar leptoquarks to explain the anomalies in the semi-leptonic decays of $B$-mesons and the discrepancies in the lepton $(g-2{)}_l$'s including the recent results at Fermilab E989. The $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ anomalies can be accommodated by the specific couplings for triplet and singlet leptoquarks, respectively, subject to the bounds from $B\to K\nu \bar{\nu }$. We discuss the correlation between the leptonic signatures from leptoquarks such as $\mu \to e\gamma$ and the electric dipole moment of electron and show that desirable neutrino masses can be generated dominantly by top-quark loops in the extension of the model with several doublet leptoquarks.

Comments: 22 pages, 5 figures. v2: updated with the recent data from Fermilab E989, references added, v3: improved discussion, v4: typos corrected, accepted version for Phys. Rev. D