Leptoquarks: Neutrino masses and accelerator phenomenology

TL;DR

This paper explores how leptoquarks can generate neutrino masses via loop processes, predicts their collider signatures and decay patterns, and discusses constraints from neutrino oscillation data and LHC phenomenology.

Contribution

It provides a detailed calculation of neutrino mass matrices in leptoquark models and links neutrino data to collider signatures, including decay branching ratios and lepton flavor violation.

Findings

Leptoquark models can generate neutrino masses consistent with oscillation data.

Predicted large lepton flavor violating signals at the LHC.

Heavier leptoquarks decay into lighter states plus Higgs or gauge bosons.

Abstract

Leptoquark-Higgs interactions induce mixing between leptoquark states with different chiralities once the electro-weak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1-loop order. Here we calculate the neutrino mass matrix and explore the constraints on the parameter space enforced by the assumption that LQ-loops explain current neutrino oscillation data. LQs will be produced at the LHC, if their masses are at or below the TeV scale. Since the fermionic decays of LQs are governed by the same Yukawa couplings, which are responsible for the non-trivial neutrino mass matrix, several decay branching ratios of LQ states can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. In addition, the model predicts that, if kinematically possible, heavier LQs decay into lighter ones plus either a standard model Higgs boson or a $Z^0/W^{\pm}$ gauge boson. Thus, experiments at the LHC might be able to exclude the LQ mechanism as explanation of neutrino data.