On the origin of the D0 like-sign dimuon charge asymmetry

TL;DR

This paper explores the D0 experiment's dimuon charge asymmetry, suggesting it could be explained by CP-violating New Physics in meson mixing and semileptonic decays, within current experimental bounds.

Contribution

It proposes that CP violation in semileptonic b and c decays could account for the asymmetry, offering a new perspective on potential New Physics effects.

Findings

CP asymmetry in semileptonic b decays could reach 0.3%

CP asymmetry in semileptonic c decays could reach 1%

These effects are consistent with current experimental bounds

Abstract

We reconsider the recent observation by the D0 experiment of a sizable like-sign dimuon charge asymmetry, highlighting that it could be affected by CP-violating New Physics contributions not only in Bd- and Bs-meson mixings, but also in semileptonic decays of b and c quarks producing muons. The D0, measurement could be reconciled with the Standard Model expectations for neutral-meson mixings, provided that the CP asymmetry in semileptonic b (c) decays reaches 0.3 % (1%). Such effects, which lie within the available (rather loose) experimental bounds, would be clear indications of New Physics and should be investigated experimentally.