A Window on the CP-violating Phases of MSSM from Lepton Flavor Violating Processes

TL;DR

This paper explores how measuring transverse polarization in lepton flavor violating processes can reveal CP-violating phases in the MSSM, helping to resolve parameter degeneracies.

Contribution

It derives formulas linking transverse polarization to MSSM couplings and demonstrates how combined measurements can determine CP-violating phases.

Findings

Polarization measurements depend on MSSM parameters.

Combining observables helps resolve parameter degeneracies.

Electric dipole moment data complements polarization info.

Abstract

It has recently been shown that by measuring the transverse polarization of the final particles in the LFV processes $\mu \to e\gamma$, $\mu \to eee$ and $\mu N\to e N$, one can derive information on the CP-violating phases of the underlying theory. We derive formulas for the transverse polarization of the final particles in terms of the couplings of the effective potential leading to these processes. We then study the dependence of the polarizations of $e$ and $\gamma$ in the $\mu \to e \gamma$ and $\mu N \to e N$ on the parameters of the Minimal Supersymmetric Standard Model (MSSM). We show that combining the information on various observables in the $\mu \to e\gamma$ and $\mu N\to e N$ search experiments with the information on the electric dipole moment of the electron can help us to solve the degeneracies in parameter space and to determine the values of certain phases.