1202.5105 (Diganta Das et al.)

Isolating New Physics Effects from Hadronic Form Factor Uncertainties in
B\to K^* \ell^+\ell^-    [PDF]

Diganta Das, Rahul Sinha

The discovery of New Physics, using weak decays of mesons is difficult due to
intractable strong interaction effects needed to describe it. We show how the
multitude of "related observables" obtained from B\to K^* \ell^+\ell^-, can
provide many new "clean tests" of the Standard Model. The hallmark of these
tests is that several of them are independent of the unknown form factors
required to describe the decay using heavy quark effective theory. We derive a
relation between observables that is free of form factors and Wilson
coefficients, the violation of which will be an unambiguous signal of New
Physics. We also derive other relations between observables and form factors
that are independent of Wilson coefficients and enable verification of hadronic
estimates. We find that the allowed parameter space for observables is very
tightly constrained in Standard Model, thereby providing clean signals of New
Physics. The relations derived will provide unambiguous signals of New Physics
if it contributes to these decays.

View original: http://arxiv.org/abs/1202.5105