Probing long-lived doubly charged scalar in the Georgi-Machacek model at the LHC and in far detectors

TL;DR

This paper explores the detection prospects of long-lived doubly charged scalars in the Georgi-Machacek model at the LHC and far detectors, highlighting potential signals and parameter space coverage.

Contribution

It introduces the analysis of long-lived doubly charged scalars in the GM model and evaluates detection strategies at both collider and far detectors.

Findings

Limits on mixing angle $ heta_H$ can reach $ ext{sin} heta_H extless 10^{-3}$

Detection strategies include displaced vertices, showers, and stable charged particles

Parameter space with scalar masses between 50 GeV and 180 GeV can be probed

Abstract

Searching for long-lived particles (LLPs) beyond the Standard Model (SM) is a promising direction in collider experiments. The Georgi-Machacek (GM) model extends the scalar sector in the SM by introducing various new scalar bosons. In this study, we focus on the parameter space that allows the light doubly charged scalar to become long-lived. This light doubly charged scalar is fermophobic and predominantly decays into a pair of on-shell or off-shell same-sign $W$ bosons. We investigate three types of signal signatures at the LHC: displaced vertices in the inner tracking detector, displaced showers in the muon system, and heavy stable charged particles. Additionally, we analyze the potential for detecting such doubly charged scalars in far detectors, including ANUBIS, MATHUSLA, FACET, FASER, CODEX-b, MoEDAL-MAPP and AL3X. By combining the LLP searches at the LHC and in far detectors, we project that the limits on the mixing angle, $\theta_H$, (between the doublet and triplets) can cover most of the parameter space with $\sin\theta_H\lesssim 10^{-3}$ for the mass range of long-lived doubly charged scalars between $50$ GeV to $180$ GeV, assuming the full integrated luminosity at the LHC and HL-LHC.