Eur. Phys. J. C (2013) 73: 2646
https://doi.org/10.1140/epjc/s10052-013-2646-9

Regular Article - Theoretical Physics

New physics in B→K ^∗ μμ?

¹ Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL, 60510, USA
² PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099, Mainz, Germany

^* e-mail: waltmann@fnal.gov

Received: 19 August 2013
Revised: 8 October 2013
Published online: 26 November 2013

Abstract

Recent experimental results on angular observables in the rare decay B→K ^∗ μ ⁺ μ ⁻ show significant deviations from Standard Model predictions. We investigate the possibility that these deviations are due to new physics. Combining all relevant data on b→s rare decays, we show that a consistent explanation of most anomalies can be obtained by new physics contributing simultaneously to the semi-leptonic vector operator O ₉ and its chirality-flipped counterpart . A partial explanation is possible with new physics in O ₉ or in dipole operators only. We study in detail the implications for models of new physics, in particular the minimal supersymmetric standard model, models with partial compositeness and generic models with flavour-changing Z′ bosons. In all considered models, contributions to B→K ^∗ μ ⁺ μ ⁻ of the preferred size imply a spectrum close to the TeV scale. We stress that measurements of CP asymmetries in B→K ^∗ μ ⁺ μ ⁻ could provide valuable information to narrow down possible new physics explanations.