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Pseudoscalar Higgs boson production at hadron colliders in NNLO QCD

Charalampos Anastasiou, Kirill Melnikov

TL;DR

The paper computes NNLO QCD corrections to direct pseudoscalar Higgs boson production in hadron collisions within the MSSM under the regime $m_A \ll 2m_t$, using a heavy-top effective Lagrangian and a γ5 treatment in the Larin scheme. It derives analytic NNLO partonic cross-sections for all contributing channels, expressed through $\hat{\sigma}_{ij} = \sigma_0^{(A)} [ \phi_{ij}^{(0)} + (\alpha_s/\pi) \phi_{ij}^{(1)} + (\alpha_s/\pi)^2 \phi_{ij}^{(2)} ]$, and provides explicit NNLO differences $\delta \phi^{(2)}_{ij}$ relative to the scalar case, with scales fixed to $\mu_f=\mu_r=m_A$. Hadronic predictions are obtained by convolving these NNLO partonic results with approximate NNLO PDFs (MRST), yielding LHC and Tevatron cross-sections that exhibit improved perturbative stability but large absolute corrections. The key findings show a ~$30\%$ NNLO increase over LO at the LHC (with ~15% residual scale dependence) and a ~3x LO enhancement at the Tevatron, indicating convergence similar to the SM Higgs case and providing robust predictions for pseudoscalar Higgs searches.

Abstract

We compute the total cross-section for direct production of the pseudoscalar Higgs boson in hadron collisions at next-to-next-to-leading order (NNLO) in perturbative QCD. The O(alpha_s^2) QCD corrections increase the NLO production cross-section by approximately 20-30 per cent.

Pseudoscalar Higgs boson production at hadron colliders in NNLO QCD

TL;DR

The paper computes NNLO QCD corrections to direct pseudoscalar Higgs boson production in hadron collisions within the MSSM under the regime , using a heavy-top effective Lagrangian and a γ5 treatment in the Larin scheme. It derives analytic NNLO partonic cross-sections for all contributing channels, expressed through , and provides explicit NNLO differences relative to the scalar case, with scales fixed to . Hadronic predictions are obtained by convolving these NNLO partonic results with approximate NNLO PDFs (MRST), yielding LHC and Tevatron cross-sections that exhibit improved perturbative stability but large absolute corrections. The key findings show a ~ NNLO increase over LO at the LHC (with ~15% residual scale dependence) and a ~3x LO enhancement at the Tevatron, indicating convergence similar to the SM Higgs case and providing robust predictions for pseudoscalar Higgs searches.

Abstract

We compute the total cross-section for direct production of the pseudoscalar Higgs boson in hadron collisions at next-to-next-to-leading order (NNLO) in perturbative QCD. The O(alpha_s^2) QCD corrections increase the NLO production cross-section by approximately 20-30 per cent.

Paper Structure

This paper contains 4 sections, 18 equations, 3 figures.

Table of Contents

  1. Introduction
  2. Partonic Cross-Sections
  3. Numerical Results
  4. Conclusions

Figures (3)

  • Figure 1: The pseudoscalar Higgs boson production cross-section at the LHC at leading (dotted), next-to-leading (dashed-dotted) and next-to-next-to-leading (solid) order. The two curves for each case correspond to $\mu_r = \mu_f = m_A/2$ (upper) and $\mu_r = \mu_f = 2 m_A$ (lower).
  • Figure 2: The pseudoscalar Higgs boson production cross-section at the Tevatron at leading (solid), next-to-leading (dashed) and next-to-next-to-leading (dotted) order. The two curves for each case correspond to $\mu_r = \mu_f = m_A/2$ (upper) and $\mu_r = \mu_f = 2 m_A$ (lower).
  • Figure 3: The pseudoscalar Higgs boson production cross-section at the LHC at leading (dotted), next-to-leading (dashed) and next-to-next-to-leading (solid) order as the function of factorization and renormalization scale $\mu$. The mass of the Higgs boson is $115~{\rm GeV}$.