A model-independent analysis of transitions with GAMBIT ’s FlavBit

Jihyun Bhom; Marcin Chrzaszcz; Farvah Mahmoudi; Markus T. Prim; Pat Scott; Martin White

doi:10.1140/epjc/s10052-021-09840-z

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 1076
https://doi.org/10.1140/epjc/s10052-021-09840-z

Regular Article - Theoretical Physics

A model-independent analysis of $b \to s μ^{+} μ^{-}$ $b{\rightarrow }s\mu ^{+}\mu ^{-}$ transitions with GAMBIT ’s FlavBit

Jihyun Bhom¹^a, Marcin Chrzaszcz¹^b, Farvah Mahmoudi²^,3^c, Markus T. Prim⁴, Pat Scott⁵^,6 and Martin White⁷

¹ Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
² Univ Lyon, Univ Lyon 1, CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, UMR5822, 69622, Villeurbanne, France
³ Theoretical Physics Department, CERN, 1211, Geneva 23, Switzerland
⁴ Institute of Experimental Particle Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
⁵ School of Mathematics and Physics, The University of Queensland, St. Lucia, 4072, Brisbane, QLD, Australia
⁶ Department of Physics, Imperial College London, SW7 2AZ, South Kensington, UK
⁷ Department of Physics, University of Adelaide, 5005, Adelaide, SA, Australia

^a jihyun.bohm@cern.ch
^b marcin.chrzaszcz@cern.ch
^c mahmoudi@in2p3.fr

Received: 26 May 2021
Accepted: 17 November 2021
Published online: 7 December 2021

Abstract

The search for flavour-changing neutral current effects in B-meson decays is a powerful probe of physics beyond the Standard Model. Deviations from SM behaviour are often quantified by extracting the preferred values of the Wilson coefficients of an operator product expansion. We use the FlavBit module of the GAMBIT package to perform a simultaneous global fit of the Wilson coefficients $C_{7}$ $$C_7$$ , $C_{9}$ $$C_9$$ , and $C_{10}$ $C_{10}$ using a combination of all current data on $b \to s μ^{+} μ^{-}$ $b{\rightarrow }s\mu ^{+}\mu ^{-}$ transitions. We further extend previous analyses by accounting for the correlated theoretical uncertainties at each point in the Wilson coefficient parameter space, rather than deriving the uncertainties from a Standard Model calculation. We find that the best fit deviates from the SM value with a significance of 6.6 $σ$ $\sigma$ . The largest deviation is associated with a vector coupling of muons to b and s quarks.

© The Author(s) 2021

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