SAIP2025

Observation of 152 GeV charged scalar at future lepton colliders

9 Jul 2025, 09:40

20m

Solomon Mahlangu House (University of the Witwatersrand, Johannesburg)

Oral Presentation Track B - Nuclear, Particle and Radiation Physics Nuclear, Particle and Radiation Physics-2

Speaker

Dr Siddharth Prasad Maharathy (School of Physics and Institute for Collider Particle Physics, University of the Witwatersrand)

Description

The statistical significance of the "multi-lepton anomalies"—the discrepancies in the channels with multiple leptons, missing energy, and potentially ($b$)jets in the final states with the SM prediction—indicates the production of a scalar with a mass between 145 GeV and 155 GeV that is beyond the standard model. The associated production of a narrow scalar resonance of mass $\approx$ 152 GeV, with a significance of 5.4 $\sigma$ has been reported with the $\gamma \gamma$, $Z\gamma$, and WW final state. The requirement of the new scalar to decay dominantly to $WW$ final state by the anomalies and the absence of any excess in $ZZ$ final state significantly predicts the new scalar to be part of $Y=0$ scalar-triplet. The model contains a CP-even neutral Higgs ($\Delta^0$), and two charged Higgs bosons ($\Delta^\pm$), which are quasi-degenerate in mass. In this article, we focus on the possibility of finding the aforementioned predicted $\approx$ 152 GeV BSM charged scalar at the future proposed $e^+e^-$ collider. We emphasize on the pair production of the charged scalars, $e^+e^- \to \Delta^\pm \Delta^\mp$ and scrutinize various signal regions depending on the decay products of $\Delta^\pm$.