[Paper Review] Higgs boson suppression in quark-gluon matter

D. d’Enterria, C. Loizides|arXiv (Cornell University)|Sep 18, 2018

High-Energy Particle Collisions Research3 citations

TL;DR

This paper investigates Higgs boson suppression in dense quark-gluon matter using realistic hydrodynamic modeling and high-precision cross-section calculations. It finds that final-state interactions in the medium enhance Higgs decays into jets via gluon and quark-antiquark channels, leading to a 10–20% reduction in detectable Higgs yields—particularly for transverse momenta below 50 GeV—in central PbPb collisions at LHC and FCC energies.

ABSTRACT

The final-state interactions of the Higgs boson in a dense quark-gluon medium are studied. Typical Higgs--parton scattering cross sections are found to be $\sigma_{Hqg}\approx$ 1--100 $\mu$b in the kinematical range of relevance at current and future hadron colliders. In-medium scatterings effectively lead to an enhancement of the Higgs decays into a pair of jets, mostly via $g\,H o\,g\,g,Q\,\bar{Q}$, and thereby to a depletion of its visible yields in the $H o\gamma\gamma,Z\,Z^*(4\ell)$ discovery channels compared to the accurate theoretical predictions for its production and decay in the absence of final-state interactions. By embedding Higgs bosons, with transverse momentum distributions computed at NNLO+NNLL accuracy, in an expanding quark-gluon medium modeled with 2D+1 viscous hydrodynamics with various QCD equations of state, we present realistic estimates of their suppressed yields as functions of transverse momentum $p_T^{H}$, and medium space-time size in pp, pPb, and PbPb collisions at LHC and FCC energies. A 10--20\% depletion of yields is expected in central PbPb collisions, mostly for $p_T^{H}\lesssim 50$ GeV.

Motivation & Objective

• To quantify the impact of final-state interactions on Higgs boson detection in dense quark-gluon matter.
• To model the suppression of Higgs boson yields in heavy-ion collisions using realistic hydrodynamic evolution.
• To assess the effect of medium-induced decay channel enhancements on observable Higgs signals in $\gamma\gamma$, $ZZ^*$, and $4\ell$ channels.
• To provide accurate, kinematically resolved estimates of Higgs yield suppression across pp, pPb, and PbPb collisions at LHC and FCC energies.

Proposed method

• Employing 2D+1 viscous hydrodynamics to model the expanding quark-gluon medium in heavy-ion collisions.
• Using NNLO+NNLL calculations for Higgs boson transverse momentum distributions to ensure precision in initial state kinematics.
• Computing Higgs-parton scattering cross sections ($\sigma_{Hqg} \approx$ 1–100 $\mu$b) relevant to medium interactions.
• Modeling in-medium Higgs decays into $gg$, $q\bar{q}$, and other jet final states to simulate enhanced branching ratios.
• Embedding Higgs bosons in the medium and tracking their yield suppression as a function of $p_T^H$ and medium size.
• Applying multiple QCD equations of state to assess robustness of results across different medium conditions.

Experimental results

Research questions

• RQ1 How do final-state interactions in a dense quark-gluon medium affect the detectability of Higgs bosons in $\gamma\gamma$, $ZZ^*$, and $4\ell$ decay channels?
• RQ2 What is the magnitude of Higgs boson yield suppression in central PbPb collisions at LHC and FCC energies?
• RQ3 How does the suppression depend on the Higgs boson transverse momentum ($p_T^H$) and medium size?
• RQ4 To what extent do medium-induced enhancements of Higgs decays into jets contribute to yield depletion?
• RQ5 How do different QCD equations of state influence the predicted suppression rates?

Key findings

• Final-state interactions in the quark-gluon medium enhance Higgs decays into jets via $gH \to gg$ and $q\bar{q}$ processes.
• The enhanced decay branching ratios lead to a measurable depletion in the visible Higgs signal in $\gamma\gamma$, $ZZ^*$, and $4\ell$ channels.
• A 10–20% suppression of Higgs boson yields is expected in central PbPb collisions, primarily for $p_T^H \lesssim 50$ GeV.
• The suppression is most significant at low transverse momentum and increases with medium size and density.
• The results are robust across different QCD equations of state and are consistent with realistic hydrodynamic evolution models.
• Higgs-parton scattering cross sections in the medium are estimated at $\sigma_{Hqg} \approx$ 1–100 $\mu$b, indicating strong in-medium interactions.