Understanding the correlation between $(g-2)_\mu$ and $\mu \rightarrow e \gamma$ in the MSSM

TL;DR

This paper explores the relationship between the muon anomalous magnetic moment and the decay $oldsymbol{ ext{mu} o e ext{gamma}}$ within the MSSM, analyzing how different parameter scenarios influence their correlation and resulting experimental bounds.

Contribution

It provides an extensive survey of correlations between $a_\mu$ and $ ext{BR}(\mu \to e \gamma)$ in the MSSM, including benchmark points and the impact of diagram cancellations.

Findings

Strong correlations in single-diagram dominated scenarios

Cancellations weaken correlations across the MSSM parameter space

Predictable order of magnitude for $ ext{BR}( ext{mu} o e ext{gamma})$ given flavor violation

Abstract

The supersymmetric contributions to the muon anomalous magnetic moment $a_\mu$ and to the decay $\mu\to e\gamma$ are given by very similar Feynman diagrams. Previous works reported correlations in specific scenarios, in particular if $a_\mu$ is dominated by a single diagram. In this work we give an extensive survey of the possible correlations. We discuss examples of single-diagram domination with particularly strong correlations, and provide corresponding benchmark parameter points. We show how the correlations are weakened by significant cancellations between diagrams in large parts of the MSSM parameter space. Nevertheless, the order of magnitude of $\text{BR}(\mu \to e \gamma)$ for a fixed flavor-violating parameter can often be predicted. We summarize the behavior by plotting the correlations as well as resulting bounds on the flavor-violating parameters under various assumptions on the MSSM spectrum.