Same-Sign Tetra-Leptons from Type II Seesaw

TL;DR

This paper explores a novel collider signature of same-sign tetra-leptons arising from the type II seesaw mechanism, analyzing production processes and potential observability at the LHC.

Contribution

It introduces a new collider signature of same-sign tetra-leptons from Higgs triplet decays in the type II seesaw model and provides a detailed LHC analysis for this process.

Findings

Identifies parameter regions with sizable same-sign tetra-lepton signals.

Calculates production cross-sections for the tetra-lepton signature.

Proposes an LHC analysis strategy for detecting the signal.

Abstract

The type II seesaw mechanism introduces a hypercharged Higgs triplet to explain the observed neutrino masses and mixing. Among three triplet components, the doubly charged Higgs boson can be the lightest and decay mainly to same-sign di-leptons. Furthermore, the heavier singly charged or neutral Higgs boson produces a doubly charged Higgs boson through its fast gauge decay. This leads to a novel signature of same-sign tetra-leptons resulting from a pair production of same-sign doubly charged Higgs bosons caused by the nearly degenerate neutral scalar mixing which can be sizable for an appropriate choice of the model parameters. After studying production cross-sections for the same-sign tetra-lepton signal in the parameter space of the mass splitting among triplet components and the triplet vacuum expectation value, we provide a LHC analysis of the same-sign tetra-lepton signal for a benchmark point chosen to maximize the event number.