Flavoured axions in the tail of Bq → μ+μ− and B → γ* form factors

Journal of High Energy Physics

Johannes Albrecht¹  Emmanuel Stamou²  Roman Zwicky³  Robert Ziegler⁴ 

[1] Fakultät für Physik, TU Dortmund, Otto-Hahn-Str. 4, D-44221, Dortmund, Germany;Fakultät für Physik, TU Dortmund, Otto-Hahn-Str. 4, D-44221, Dortmund, Germany;Institut de Théorie des Phénomenes Physiques, EPFL, Rte Cantonale, 1015, Lausanne, Switzerland;Higgs Centre for Theoretical Physics, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, EH9 3FD, Edinburgh, U.K.;Theoretical Physics Department, CERN, 23 1211, Geneva, Switzerland;Institut für Theoretische Teilchenphysik, Karlsruhe Institute for Technology, Wolfgang-Gaede Straße 1, 76131, Karlsruhe, Germany;

关键词: Perturbative QCD;    Beyond Standard Model;   

DOI  :  10.1007/JHEP09(2021)139

来源: Springer

【 摘 要 】

We discuss how LHC di-muon data collected to study Bq → μμ can be used to constrain light particles with flavour-violating couplings to b-quarks. Focussing on the case of a flavoured QCD axion, a, we compute the decay rates for Bq → μμa and the SM background process Bq → μμγ near the kinematic endpoint. These rates depend on non-perturbative Bq → γ(*) form factors with on- or off-shell photons. The off-shell form factors — relevant for generic searches for beyond-the-SM particles — are discussed in full generality and computed with QCD sum rules for the first time. This includes an extension to the low-lying resonance region using a multiple subtracted dispersion relation. With these results, we analyse available LHCb data to obtain the sensitivity on Bq → μμa at present and future runs. We find that the full LHCb dataset alone will allow to probe axion-coupling scales of the order of 106 GeV for both b → d and b → s transitions. As a spin-off application of the off-shell form factors we further analyse the case of light, Beyond the Standard Model, vectors.

【 授权许可】

CC BY