New Physics in B-Bbar mixing in the light of recent LHCb data

TL;DR

This paper analyzes various model-independent scenarios of New Physics in B meson mixing using recent LHCb data, highlighting the challenges and proposing a comprehensive scenario that fits all observations.

Contribution

It introduces a new scenario with NP in both mass and decay matrices of B mesons, capable of accommodating all current experimental data.

Findings

Standard Model disfavored at 2.4 sigma in uncorrelated NP scenario

Recent LHCb data constrains NP explanations of semileptonic CP asymmetry

A combined NP scenario in M_12 and Gamma_12 fits all current measurements

Abstract

We perform model-independent statistical analyses of three scenarios accommodating New Physics (NP) in Delta F=2 flavour-changing neutral current amplitudes. In a scenario in which NP in B_d-B_d-bar and B_s-B_s-bar is uncorrelated, we find the parameter point representing the Standard-Model disfavoured by 2.4 standard deviations. However, recent LHCb data on B_s neutral-meson mixing forbid a good accommodation of the D0 data on the semileptonic CP asymmetry A_SL. We introduce a fourth scenario with NP in both M_12^d,s and Gamma_12^d,s, which can accommodate all data. We discuss the viability of this possibility and emphasise the importance of separate measurements of the CP asymmetries in semileptonic B_d and B_s decays. All results have been obtained with the CKMfitter analysis package, featuring the frequentist statistical approach and using Rfit to handle theoretical uncertainties.