Pati-Salam explanations of the B-meson anomalies

Abstract

We provide a combined explanation of the increasingly tantalizing $B$-meson anomalies, both in $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$, in the Pati-Salam model with minimal matter content. This well-known model, based on the gauge group $SU(4{)}_{LC}\times SU(2{)}_L\times SU(2{)}_R$, naturally contains a variety of scalar leptoquarks with related and restricted couplings. In particular we show that the seesaw-motivated scalar leptoquark within the representation $(\overline{10},3,1)$ and its right-handed parity partner $(\overline{10},1,3)$ can solve both anomalies while making testable predictions for related observables such as $B\to K\nu \nu$ and $B\to K\mu \tau$. The solution of the $R_{K^{(\ast )}}$ anomaly alone can be related to a type-II seesaw neutrino mass structure. Explaining also $R_{D^{(\ast )}}$ requires the existence of a light right-handed neutrino, which constrains the UV structure of the model.

Comments: 26 pages, includes discussion of RGEs; to appear in JHEP