Searching for Di-Higgs Signatures of Light Charged Scalars

TL;DR

This paper explores the potential for detecting light charged scalars predicted by a two-Higgs-doublet model, which could explain certain flavor anomalies and be observed through di-Higgs search strategies at the LHC.

Contribution

It proposes a novel search strategy for light charged scalars via di-Higgs signatures, connecting flavor anomalies with collider phenomenology in a non-minimal 2HDM.

Findings

Charged Higgs pair production cross section can be significant at the LHC.

Dedicated searches could discover these scalars in Run-3 or HL-LHC.

Event rates are higher than SM Higgs pair production but with lower efficiency.

Abstract

The excess in $t\to b\overline{b}c$ observed by ATLAS points towards a charged Higgs boson with a mass around 130$\,$GeV, consistent with the expectations from the $B$ anomalies, i.e.$~R_{D^{(*)}}$ and $b\to s\ell^+\ell^-$ data. As a non-minimal flavour structure is required for an explanation of these observables, this points towards a two-Higgs-doublet model with generic Yukawa couplings. Such a scenario predicts a sizable cross section for the pair production of the charged Higgs at the Large Hadron Collider, which can be tested by recasting SM di-Higgs searches. While the predicted event rate is even higher than the one of SM Higgs pair production, the smaller efficiency (w.r.t.$~$SM Higgs pair production) reduces the signal yield. Nonetheless, dedicated searches can probe most of the interesting parameter space and lead to a discovery with Run-3 or High-Luminosity LHC data.