Analysis of the Unknown node msubsup found in MathML fragment. $ B_s^0 $ → µ+µ– decay in the MSSM

Shuang Wu,Aik Hui Chan,Choo Hiap Oh

doi:10.1051/epjconf/201920609001

Abstract

The first observation of the $ B_s^0 $ → µ+µ– decay mode was reported by the CMS and LHCb collaboration. The small branching ratio inherent to this decay mode makes it highly sensitive for probing physics beyond the SM and we analyze this decay in the framework of the Minimal Supersymmetric Standard Model (MSSM). Complete analytical expressions for the decay amplitude at the one-loop order have been obtained with the aid of computational tools such as FeynArts and FeynCalc. The general recipe for utilising these computational tools to aid theoretical calculations in the MSSM is discussed. Working in the phenomenological MSSM with reduced parameter space, a simplification of the complete analytical expression was done to express the $ B_s^0 $ → µ+µ– branching ratio as a function of these parameters. Numerical studies of the parametric dependence of $ B_s^0 $ → µ+µ– branching ratio in the phenomenological MSSM can be easily performed with the obtained analytical expression.

Highlights

Direct searches for supersymmetric (SUSY) particles in collider experiments are limited in reach by the available center-of-mass energy
This particular decay mode is interesting in that its branching ratio predicted by the SM and the Minimal Supersymmetric Standard Model (MSSM) can be different up to a few orders of magnitudes due to new sources of flavour changing neutral currents (FCNC) at the one-loop level
We only focus on this single decay mode, but such a procedure can certainly be generalized to other high energy physics processes

Summary

Introduction

Direct searches for supersymmetric (SUSY) particles in collider experiments are limited in reach by the available center-of-mass energy More accessible experiments such as electroweak precision tests are crucial as a means to probe for new physics. Perturbative calculations can be carried out in SM extensions to address the contributions of the proposed new particles and viable SM extensions need to agree with experiments within errors Such experiments place important constraints on the parameter landscapes of beyond the SM physics. This particular decay mode is interesting in that its branching ratio predicted by the SM and the Minimal Supersymmetric Standard Model (MSSM) can be different up to a few orders of magnitudes due to new sources of flavour changing neutral currents (FCNC) at the one-loop level. The interested reader may refer to [4] for further details

Numerical results within the SM

Numerical results within the Phenomenological MSSM

Conclusion