Charged Lepton Flavor-violating Transitions in Color Octet Model

TL;DR

This paper investigates charged lepton flavor-violating processes within the color octet model, assessing their detectability and constraints from current and future experiments, considering TeV-scale octet particles and neutrino data.

Contribution

It provides a detailed analysis of LFV transitions in the color octet model, highlighting the potential to distinguish between singlet and triplet fermions with upcoming experimental sensitivities.

Findings

LFV decay branching ratios are below current experimental bounds.

Future experiments could differentiate between singlet and triplet fermions.

Muon conversion in nuclei could exclude triplet scenarios.

Abstract

We study charged lepton flavor-violating (LFV) transitions in the color octet model that generates neutrino mass and lepton mixing at one loop. By taking into account neutrino oscillation data and assuming octet particles of TeV scale mass, we examine the feasibility to detect these transitions in current and future experiments. We find that for general values of parameters the branching ratios for LFV decays of the Higgs and $Z$ bosons are far below current and even future experimental bounds. For LFV transitions of the muon, the present bounds can be satisfied generally, while future sensitivities could distinguish between the singlet and triplet color-octet fermions. The triplet case could be ruled out by future $\mu-e$ conversion in nuclei, and for the singlet case the conversion and the decays $\mu\to 3e,~e\gamma$ play complementary roles in excluding relatively low mass regions of the octet particles.