Alladi Ramakrishnan Hall

Corrections to the Observables in $B\to K^* l^+l^-$ Decay due to Lepton Masses

Rusa Mandal

IMSc Chennai

I will briefly discuss about my course work project in this
talk. We know that New Physics can contribute to weak decays of heavy
mesons via virtual loop processes. Important in this regard is the decay
$B \to K^*(\to K\pi) l^- l^+$ as a full angular analysis of this rare
decay gives a multitude of observables. The Hamiltonian of this decay
can be
parametrized by Wilson coefficients and QCD form factors. These form
factors are hadronic quantities and call for non-perturbative
calculations, and hence their values are not accurately calculated. So in
search of new physics it is crucial to effectively separate the effect of
new physics from hadronic uncertainties that can contribute to the decay.
In Refs. arxiv.org/abs/1205.1438 and
arxiv.org/abs/hep-ph/9907386 the authors presented several tests of
new physics that are free from hadronic form factors. These tests are
valid in the limit of zero lepton mass. In this project I retain the mass
of the leptons throughout the calculation and calculate the modifications
to the observables. At very large recoil region of the $K^*$ meson where
the mass of the leptons can no longer be neglected, this would enable us
to disentangle the genuine effects of New Physics on the observables from
the effects caused by the finite mass of the leptons.