Diquark explanation of b → sl+ l-

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 5 sigma level. While previously a lepton flavor universality violating effect was preferred, the new R(K-(*)) and Bs -> mu+ mu- measurements are now compatible with the Standard Model, favoring a lepton flavor universal beyond the Standard Model contribution to C-9. 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 ((s) over bar gamma(mu)P(L)b) ((c) over bar gamma(mu)P(L)c) operator at tree-level, which then mixes into O-9 via an off-shell photon penguin. This setup allows for a lepton flavor universal effect of C-9 approximate to -0.5, without violating bounds from Delta Ms, Delta Gamma, B -> Xs gamma and D-0 - (D) over bar (0) 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 (c) over bars rate.

Automated summary

The discrepancies between b -> sl(+) l(-) data and the corresponding Standard Model predictions suggest the existence of new physics with a new Wilson coefficient. The chiral nature of heavy new physics and the constraints from lepton flavor violation pose a challenge for model building.