Pair production of neutral Higgs bosons at the CERN Large Hadron Collider

TL;DR

This work analyzes neutral Higgs-boson pair production at the LHC in the MSSM by computing LO cross sections for q q̄ annihilation and gg fusion, including both quark and squark loop contributions. It demonstrates that Yukawa-enhanced bb̄ channels can dominate in several cases, and that squark-loop corrections to gg fusion can be large (up to ~90%) but are highly process-dependent. The authors provide compact analytic expressions for the tree-level and loop amplitudes within a constrained SUGRA-inspired MSSM, and evaluate hadronic cross sections across mA0 and tanβ, revealing substantial variation and meaningful event yields at design luminosities. These results inform Higgs-pair search strategies at the LHC and emphasize the role of SUSY-loop effects and bottom-quark Yukawa couplings in MSSM phenomenology.

Abstract

We study the hadroproduction of two neutral Higgs bosons in the minimal supersymmetric extension of the standard model, which provides a handle on the trilinear Higgs couplings. We include the contributions from quark-antiquark annihilation at the tree level and those from gluon-gluon fusion, which proceeds via quark and squark loops. We list compact results for the tree-level partonic cross sections and the squark loop amplitudes, and we confirm previous results for the quark loop amplitudes. We quantitatively analyze the hadronic cross sections at the CERN Large Hadron Collider assuming a favorable supergravity-inspired scenario.

Figures (8)

• Figure 1: Tree-level Feynman diagrams for $q\bar{q}\to\phi_1\phi_2$, with (a) $\phi_1\phi_2=h^0h^0,h^0H^0,H^0H^0,A^0A^0$ and (b) $\phi_1\phi_2=h^0A^0,H^0A^0$, in the MSSM.
• Figure 2: One-loop Feynman diagrams for $gg\to\phi_1\phi_2$, with (a) $\phi_1\phi_2=h^0h^0,h^0H^0,H^0H^0,A^0A^0$ and (b) $\phi_1\phi_2=h^0A^0,H^0A^0$, due to virtual quarks and squarks in the MSSM.
• Figure 3: Total cross sections $\sigma$ (in fb) of $pp\to h^0h^0+X$ via $b\bar{b}$ annihilation (dashed lines) and $gg$ fusion (solid lines) at the LHC (a) as functions of $m_{A^0}$ for $\tan\beta=3$ (starting at $m_{A^0}=240$ GeV) and 30 (starting at $m_{A^0}=90$ GeV); and (b) as functions of $\tan\beta$ for $m_{A^0}=300$ GeV. For comparison, also the quark loop contribution to $gg$ fusion (dotted lines) is shown.
• Figure 4: Total cross sections $\sigma$ (in fb) of $pp\to h^0H^0+X$ via $b\bar{b}$ annihilation (dashed lines) and $gg$ fusion (solid lines) at the LHC (a) as functions of $m_{A^0}$ for $\tan\beta=3$ (starting at $m_{A^0}=240$ GeV) and 30 (starting at $m_{A^0}=90$ GeV); and (b) as functions of $\tan\beta$ for $m_{A^0}=300$ GeV. For comparison, also the quark loop contribution to $gg$ fusion (dotted lines) is shown.
• Figure 5: Total cross sections $\sigma$ (in fb) of $pp\to H^0H^0+X$ via $b\bar{b}$ annihilation (dashed lines) and $gg$ fusion (solid lines) at the LHC (a) as functions of $m_{A^0}$ for $\tan\beta=3$ (starting at $m_{A^0}=240$ GeV) and 30 (starting at $m_{A^0}=90$ GeV); and (b) as functions of $\tan\beta$ for $m_{A^0}=300$ GeV. For comparison, also the quark loop contribution to $gg$ fusion (dotted lines) is shown.