Alladi Ramakrishnan Hall

Unearthing the pattern of lepton flavour universality violations

Abhishek Iyer

INFN, Naples

Lepton Flavour universality violations in the semileptonic decays of B
mesons constitute one of the strongest hints for BSM physics. However, the
verdict is yet to be out on the exact pattern of the anomalies: Either
driven solely by the muons or involving a combination of both leptons. With
the aid of current and future experiments, we propose several checks in an
attempt to unearth the nature of the anomalies. Correlation with different
experiments and flavour sectors is facilitated by the assumption of minimal
extension to the SM with a flavour symmetry. In this instance, we consider
a model with a heavy neutral vector (Z'). The correlations developed are
three-fold: A) We demonstrate how different pattern of the solutions to the
anomalies can lead to different predictions for the rare K decays. These
can be verified at the ongoing NA62 experiment at CERN. B) We test the
viability of pure electron contributions by considering the implications
from the recent measurements on the weak charge of proton $Q_W^p$ and the
Caesium atom $Q_W^{Cs}$. The conclusion is characterized by
different limiting behaviour depending on the chirality of the lepton
current. C) Finally, in the context of high pT searches at the LHC, we
construct measures of non-universality to disentangle the detector effects to those from the actual differential coupling of the heavy neutral vector to the leptons.