Non-local contributions to b->smumu processes and constraints on sbcc operators from data

Rare b->smumu decays suffer from persistent and hard-to-quantify non-local contributions that arise primarily from sbcc four-quark operators.

As part of this project, we will first constrain the potential size of the Wilson coefficients of said four-quark operators from experimental measurements. Our approach will involve computing a large set of two-point functions between the four-quark operators and a variety of interpolating currents at spacelike momenta. The measured amplitudes of hadronic B->K charmonium give rise to poles in the two-point functions at timelike momenta.

Extrapolating from the spacelike to the timelike region, we will be able to infer information on the Wilson coefficients.

Next, we will transfer the information obtained to theory predictions of b->smumu processes. In this way, we will not be forced to assume Standard-Model-like contributions by the four-quark operators. This will remove a hardly quantifiable systematic uncertainty from the theory predictions.

The overall project will make use of a variety of methods, including dispersive bounds, operator-product expansions, and a variety of statistical methods from the field of Bayesian statistics.