Abstract
The discrepancies between b→sℓ+ℓ− data and the corresponding Standard Model predictions point to the existence of new physics with a significance at the 5σ level. While previously a lepton flavor universality violating effect was preferred, the new R(K(*)) and Bs→μ+μ− measurements are now compatible with the Standard Model, favoring a lepton flavor universal beyond the Standard Model contribution to C9. Since heavy new physics is generally chiral, and because of the stringent constraints from charged lepton flavor violation, this poses a challenge for model building. In this article, we point out a novel possibility: a diquark, i.e., a colored scalar, induces the Wilson coefficient of the (¯sγμPLb)(¯cγμPLc) operator at tree-level, which then mixes into O9 via an off-shell photon penguin. This setup allows for a lepton flavor universal effect of C9≈−0.5, without violating bounds from ΔMs, ΔΓ, B→Xsγ and D0−¯D0 mixing. This scenario predicts a small and negative C′9 and a light diquark, preferably with a mass around 500 GeV, as compatible with the CMS di-dijet analysis, and a deficit in the inclusive b→c¯cs rate.
Crivellin, Andreas