Heavy Higgs signal-background interference in gg --> VV in the Standard Model plus real singlet

TL;DR

This paper investigates how interference effects between a heavy Higgs boson, the continuum background, and the light Higgs influence the gg --> VV processes in the Standard Model extended with a real singlet, affecting the Higgs signal shape at the LHC.

Contribution

It provides a detailed analysis of interference effects in gg --> VV processes within the extended Standard Model and introduces a public simulation program for these effects.

Findings

Interference effects can reach up to 100% in cross sections.

A specific invariant mass cut reduces interference to about 10%.

Full interference significantly alters the heavy Higgs line shape.

Abstract

For the Standard Model extended with a real scalar singlet field, the modification of the heavy Higgs signal due to interference with the continuum background and the off-shell light Higgs contribution is studied for gg --> ZZ, WW --> 4 lepton processes at the Large Hadron Collider. Interference effects can range from O(10%) to O(1) effects for integrated cross sections. Despite a strong cancellation between the heavy Higgs-continuum and the heavy Higgs-light Higgs interference, the full interference is clearly non-negligible and modifies the heavy Higgs line shape. A |M_VV - M_h2| < Gamma_h2 cut mitigates interference effects to O(10%) or less. A public program that allows to simulate the full interference is presented.