Speaker
Description
The statistical significance of the multilepton anomaly - the discrepancies in the channels with multiple leptons, missing energy, and (b-) jets in the final states with the SM prediction -indicates the production of a scalar with mass between 145 and 155 GeV that is beyond the standard model. The associated production of a narrow scalar resonance of mass around 150 GeV, with a significance of $5.3\sigma$ has been reported with the analysis of $\gamma\gamma$, $Z\gamma$, and $WW$ sideband spectra in Run 2 data. The requirement of the new scalar to decay dominantly to $WW$ final state by the multi-lepton anomalies and the absence of any excess in $ZZ$ final state significantly indicates 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. Identifying the charged scalar at the LHC is difficult due to large SM backgrounds, production rates suppressed by small mixing angles
($\alpha$, $\beta$), and low detection efficiency for its moderately energetic leptons. This motivates dedicated searches at future $e^+e^-$-colliders, where the cleaner environment and well-defined initial state make $e^+ e^- \to \gamma^∗/Z \to \Delta^\pm \Delta^\mp$ the primary production channel. In this article, we focus on the possibility of finding the aforementioned predicted around 150 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 $\Delta^\pm$.
