Doubly Charged Scalar at the High-Luminosity and High-Energy LHC

TL;DR

This paper evaluates the potential of the High-Luminosity and High-Energy LHC to detect doubly charged scalars, which are relevant in beyond Standard Model physics, through their decay into charged leptons.

Contribution

It provides the first detailed sensitivity estimates for HL-LHC and HE-LHC to doubly charged scalars decaying into leptons, based on current and projected collision energies and luminosities.

Findings

HL-LHC can probe scalar masses up to 2.3 TeV.

HE-LHC can probe scalar masses up to 3 TeV.

Doubly charged scalars are promising targets for future collider searches.

Abstract

Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly charged scalars assuming they decay promptly and exclusively into charged leptons. Our study focuses on the fit to the same-sign dilepton mass spectra and it is based on proton-proton collisions at $13$ TeV, $14$ TeV and $27$ TeV with integrated luminosity of $\mathcal{L}=139 fb^{-1}, 3 $ab$^{-1}$ and $15$ab$^{-1}$. We find that HL-LHC may probe doubly charged scalars masses up to $2.3$ TeV, whereas HE-LHC can impressively probe masses up to $3$ TeV, conclusively constituting a complementary and important probe to signs of doubly charged scalars in lepton flavor violation decays and lepton-lepton colliders.