Lepton Number and Lepton Flavor Violation through Color Octet States

TL;DR

This paper explores how TeV-scale color octet particles can generate neutrino masses and mediate lepton number and flavor violating processes, providing a potential dominant contribution to neutrinoless double beta decay without conflicting with existing constraints.

Contribution

It introduces a colored seesaw mechanism with TeV-scale color octets that can dominate neutrinoless double beta decay contributions independently of lepton flavor violation constraints.

Findings

Color octet states can significantly contribute to neutrinoless double beta decay.

The model allows for dominant contributions without violating lepton flavor constraints.

Both direct and indirect contributions depend on the mass degeneracy of the octet fermions.

Abstract

We discuss neutrinoless double beta decay and lepton flavor violating decays such as $\mu-> e\gamma$ in the colored seesaw scenario. In this mechanism, neutrino masses are generated at one-loop via the exchange of TeV-scale fermionic and scalar color octets. The same particles mediate lepton number and flavor violating processes. We show that within this framework a dominant color octet contribution to neutrinoless double beta decay is possible without being in conflict with constraints from lepton flavor violating processes. We furthermore compare the "direct" color octet contribution to neutrinoless double beta decay with the "indirect" contribution, namely the usual standard light Majorana neutrino exchange. For degenerate color octet fermionic states both contributions are proportional to the usual effective mass, while for non-degenerate octet fermions this feature is not present. Depending on the model parameters, either of the contributions can be dominant.