# Signal versus Background Interference in $H^+\to t\bar b$ Signals for MSSM Benchmark Scenarios

## TL;DR

This paper studies the interference effects between heavy charged Higgs boson signals and background processes at the LHC, revealing that these effects can significantly alter search results and necessitate revised analysis strategies.

## Contribution

It demonstrates the importance of considering interference effects in charged Higgs boson searches, especially for wide resonances, using specific MSSM benchmark scenarios.

## Key findings

- Interference effects can significantly modify the expected signal yield.
- Current LHC search strategies may need adjustments to account for these effects.
- Interference effects are particularly relevant for wide charged Higgs bosons in MSSM scenarios.

## Abstract

In this paper, we investigate sizeable interference effects between a heavy charged Higgs boson signal produced via $gg\to t\bar b H^-$ (+ c.c.) followed by the decay $H^-\to b\bar t$ (+ c.c.) and the irreducible background given by $gg\to t\bar t b \bar b$ topologies at the Large Hadron Collider (LHC). We show how such effects could spoil current $H^\pm$ searches where signal and background are normally treated separately. The reason for this is that a heavy charged Higgs boson can have a large total width, in turn enabling such interferences, altogether leading to very significant alterations, both at the inclusive and exclusive level, of the yield induced by the signal alone. This therefore implies that currently established LHC searches for such wide charged Higgs bosons require modifications. We show such effects quantitatively using two different benchmark configurations of the minimal realisation of Supersymmetry, wherein such $H^\pm$ states naturally exist.