Five-lepton and six-lepton signatures from production of neutral triplet scalars in the Higgs Triplet Model

TL;DR

This paper explores unique five- and six-lepton signatures at the LHC resulting from cascade decays of neutral triplet scalars in the Higgs Triplet Model, offering new detection avenues for these particles.

Contribution

It introduces a novel cascade decay process involving neutral triplet scalars that enhances detection prospects of doubly charged scalars at the LHC.

Findings

Five- and six-lepton signals have negligible backgrounds at the LHC.

Cascade decays can produce distinctive multi-lepton signatures.

Quantitative estimates of signal magnitudes are provided.

Abstract

The neutral triplet scalars (H^0, A^0) in the Higgs Triplet Model (HTM) are difficult to detect at the LHC for the case of mass degeneracy with the singly charged (H^+) and doubly charged (H^++) scalars. A non-zero value of a specific quartic coupling in the scalar potential removes this degeneracy, and positive values of this coupling would give rise to the mass hierarchy m_{A^0,H^0} > m_{H^+} > m_{H^++}. In this scenario the decays H^0-> H^+ W^* and A^0-> H^+ W^*, followed by H^+ -> H^{++} W^*, can proceed with large branching ratios, even for small mass splittings among the triplet scalars. Such a cascade process would lead to production of H^{++}H^{--} accompanied by several virtual W bosons, and would provide a way of observing H^0 and A^0 with a signature which is different from that of the conventional production process for doubly charged scalars, q qbar -> \gamma^*, Z^* -> H^{++}H^{--}. Assuming the decay H^{++} to l^+ l^+, we quantify the magnitude of the five-lepton and six-lepton signals in these channels, which have essentially negligible backgrounds at the LHC.