Neutrinoless double beta decay and lepton number violation at the LHC

TL;DR

This paper compares the LHC's potential to detect lepton number violation with current and future neutrinoless double beta decay experiments, analyzing mechanisms and implications for particle physics.

Contribution

It provides a detailed comparison of collider and decay experiment sensitivities, and discusses how to identify the dominant mechanisms of lepton number violation.

Findings

LHC can detect signals if 0 uetaeta decay half-life is below 10^{26}-10^{27} years.

Non-observation at LHC can rule out short-range explanations for 0 uetaeta decay.

Distinct invariant mass peaks and charge asymmetry can help identify the underlying mechanism.

Abstract

We compare the discovery potential of the LHC for lepton number violating (LNV) signals with the sensitivity of current and future double beta decay experiments, assuming 0\nu\beta\beta decay is dominated by heavy particle exchange. We consider charged scalar, leptoquark and diquark mechanisms of 0\nu\beta\beta-decay, covering the 0\nu\beta\beta-decay operators with both, the smallest and largest, possible rates. We demonstrate, if 0\nu\beta\beta-decay were found with a half-life below $10^{26}-10^{27}$ ys a positive signal should show up at the LHC, except for some particular cases of the leptoquark mechanism, and vice versa, if the LHC does not find any hints for LNV, a "short-range" explanation for a finite 0\nu\beta\beta-decay half-life will be ruled out in most cases. We argue, if a positive LNV signal were found at the LHC, it is possible to identify the dominant contribution to 0\nu\beta\beta. Two different kinds of observables which could provide such "model discriminating" power are discussed: Different invariant mass peaks and the charge asymmetry.