# Charming new physics in rare B-decays and mixing?

## TL;DR

This paper explores how new physics affecting specific quark transitions could explain anomalies in rare B-decays and lifetime measurements, highlighting the importance of combined observables and renormalization effects.

## Contribution

It systematically analyzes the impact of new physics in $b o c ar{c} s$ transitions on B-physics, proposing viable scenarios consistent with current experimental constraints.

## Key findings

- Possible sizable effects in rare semileptonic B-decays.
- Renormalization-group effects can enhance impact on semileptonic decays.
- Lifetime observables at LHCb can test these scenarios.

## Abstract

We conduct a systematic study of the impact of new physics in quark-level $b \to c \bar{c} s$ transitions on $B$-physics, in particular rare $B$-decays and $B$-meson lifetime observables. We find viable scenarios where a sizable effect in rare semileptonic $B$-decays can be generated, compatible with experimental indications and with a possible dependence on the dilepton invariant mass, while being consistent with constraints from radiative $B$-decay and the measured $B_s$ width difference. We show how, if the effect is generated at the weak scale or beyond, strong renormalisation-group effects can enhance the impact on semileptonic decays while leaving radiative $B$-decay largely unaffected. A good complementarity of the different $B$-physics observables implies that precise measurements of lifetime observables at LHCb may be able to confirm, refine, or rule out this scenario.