Same-Sign Tetralepton Signature at $\mu$TRISTAN

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.

Comments: 14 pages, 3 figures