Same-Sign Tetralepton Signature at $\mu$TRISTAN

TL;DR

This paper proposes a novel same-sign tetralepton signature at 2 TeV muTRISTAN, arising from heavy neutral lepton interactions in a low-scale seesaw model, and analyzes its detectability through detailed simulations.

Contribution

It introduces a new same-sign tetralepton signal at muTRISTAN from heavy neutrino interactions, with detailed simulation showing promising detection prospects.

Findings

Identifies two production channels for the tetralepton signature.

Performs detailed simulation indicating promising detection regions.

Connects the signature to low-scale seesaw neutrino mass models.

Abstract

Naturally tiny neutrino masses can be explained by the low scale seesaw with heavy neutral lepton $N$ coupling to the neutrinophilic Higgs doublet $\Phi_\nu$, which obtains a much smaller vacuum expectation value than the standard Higgs doublet $\Phi$. Within this model, the neutrino masses originate from the new Yukawa interaction $y \overline{L}\tilde{\Phi}_\nu N$. In this paper, we propose the novel same-sign tetralepton signature at the 2 TeV same-sign muon mode $\mu^+\mu^+$ of $\mu$TRISTAN. We investigate two distinct channels of this signature, which are both generated by the Yukawa interaction $y \overline{L}\tilde{\Phi}_\nu N$. One is from the pair production of charged Higgs $\mu^+\mu^+\to H^+ H^+\to \mu^+N +\mu^+ N\to \mu^+ \mu^+ jj + \mu^+ \mu^+ jj\to 4\mu^+ + 4j$, and the other one is from the single production of charged Higgs $\mu^+\mu^+ \to \mu^+ N H^+ \to \mu^+N +\mu^+ N\to \mu^+ \mu^+ jj + \mu^+ \mu^+ jj\to 4\mu^+ + 4j$. We then perform a detailed simulation of this same-sign tetralepton signature, and obtain the promising region at $\mu$TRISTAN.