Prospects for disentangling long- and short-distance effects in the decays $B\to K^* \mu^+\mu^-$

TL;DR

This paper presents a novel amplitude analysis method to separate short-distance New Physics effects from non-local hadronic effects in $B\to K^*\mu^+\mu^-$ decays, enhancing the potential for discovering physics beyond the Standard Model.

Contribution

The study introduces an event-by-event amplitude analysis approach with advanced parametrisation to disentangle short- and long-distance effects, systematically examining the impact of parametrisation truncation.

Findings

Non-standard effects in short-distance coefficients can be successfully isolated.

Physical observables are robust against uncertainties in non-local contributions.

The method improves the precision of angular observable extraction from experimental data.

Abstract

Theory uncertainties on non-local hadronic effects limit the New Physics discovery potential of the rare decays $B\to K^*\mu^+\mu^-$. We investigate prospects to disentangle New Physics effects in the short-distance coefficients from these effects. Our approach makes use of an event-by-event amplitude analysis, and relies on the state of the art parametrisation of the non-local contributions. We find that non-standard effects in the short-distance coefficients can be successfully disentangled from non-local hadronic effects. The impact of the truncation on the parametrisation of non-local contributions to the Wilson coefficients are for the first time systematically examined and prospects for its precise determination are discussed. We find that physical observables are unaffected by these uncertainties. Compared to other methods, our approach provides for a more precise extraction of the angular observables from data.