Flavor Changing Heavy Higgs Interactions at the LHC

TL;DR

This paper investigates flavor-changing neutral Higgs decays in a general two Higgs doublet model at the LHC, focusing on the potential to observe these rare processes and their implications for Higgs physics.

Contribution

It provides a detailed analysis of flavor-changing neutral Higgs interactions in a 2HDM, highlighting the conditions under which these decays could be observed at the LHC.

Findings

Potential observability of FCNH decays at 13/14 TeV LHC

Suppressed FCNH couplings of h^0 in decoupling limit

Enhanced off-diagonal couplings of heavier scalars

Abstract

A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay $\phi^0 \to t\bar{c}+\bar{t}c$, where $\phi^0$ could be a CP-even scalar ($H^0$) or a CP-odd pseudoscalar ($A^0$). Measurement of the light 125 GeV neutral Higgs boson ($h^0$) couplings at the Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of $h^0$ approach Standard Model values. In such limit, FCNH couplings of $h^0$ are naturally suppressed by a small mixing parameter $\cos(\beta-\alpha)$, while the off-diagonal couplings of heavier neutral scalars $\phi^0$ are sustained by $\sin(\beta-\alpha) \sim 1$. We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies.