SM and MSSM Higgs Boson Production: Spectra at large transverse Momentum

TL;DR

This work analyzes the large-$p_T$ spectrum of Higgs bosons produced via gluon fusion in the Standard Model and MSSM by comparing predictions from PYTHIA, Higlu, and HQT. It reveals that in the SM the heavy-top-mass approximation yields shapes close to full results, while finite-mass effects become important at high $p_T$; in MSSM, large $\tan\beta$ enhances bottom-loop contributions, softening the spectrum and causing notable differences between tools. The authors propose a best-estimate method that combines Higlu's mass dependence with a $p_T$-dependent $K$-factor from HQT to better predict large-$p_T$ behavior, though fully massive NLO calculations are still needed for a definitive result. These findings have direct implications for Higgs searches and background discrimination at the LHC, highlighting the need for accurate treatment of mass effects and higher-order corrections.

Abstract

Strategies for Higgs boson searches require the knowledge of the total production cross section and the transverse momentum spectrum. The large transverse momentum spectrum of the Higgs boson produced in gluon fusion can be quite different in the Standard Model and the Minimal Supersymmetric Standard Model. In this paper we present a comparison of the Higgs transverse momentum spectrum obtained using the PYTHIA event generator and the HIGLU program as well as the program HQT, which includes NLO corrections and a soft gluon resummation for the region of small transverse momenta. While the shapes of the spectra are similar for the Standard Model, significant differences are observed in the spectra of Minimal Supersymmetric Standard Model benchmark scenarios with large tan(beta).

Figures (13)

• Figure 1: Leading order contribution to the SM process $g\xspace g\xspace \rightarrow\xspace h\xspace$.
• Figure 2: Dependence of the $K$ factors for the gluon-fusion cross sections on the value of $\tan\beta$. The corresponding $K$ factors obtained by omitting the bottom loops are: $K_h=1.71$, $K_H=1.76~(M_H=150\mathrm{\,Ge V}\xspace)$, $K_A=1.78~(M_A=150\mathrm{\,Ge V}\xspace)$, $K_H=1.91~(M_H=500\mathrm{\,Ge V}\xspace)$ and $K_A=1.87~(M_A=500\mathrm{\,Ge V}\xspace)$ independent of $\tan\beta$. CTEQ6L1 (CTEQ6M) parton densities Pumplin:2002vw are used for the LO (NLO) cross sections with the corresponding Higgs mass as the renormalization and factorization scale.
• Figure 3: Effective $g\xspace g\xspace h\xspace$ coupling in the heavy top mass limit.
• Figure 4: LO Feynman diagrams contributing to the transverse momentum spectrum of the SM Higgs boson, mediated by Higgs couplings to gluons.
• Figure 5: Comparison of the NLO differential cross section with the NNLL result, matched to the NLO result for SM Higgs bosons with mass $M_h=115\mathrm{\,Ge V}\xspace$ in the heavy top mass limit. The renormalization and factorization scales are chosen as the transverse mass.