QCD Corrections to SUSY Higgs Production: The Role of Squark Loops

TL;DR

The two–loop QCD corrections to the production of the neutral supersymmetric Higgs bosons via the gluon fusion mechanism at hadron colliders, including the contributions of squark loops are calculated, increasing the production rates significantly.

Abstract

We calculate the two-loop QCD corrections to the production of the neutral supersymmetric Higgs bosons via the gluon fusion mechanism at hadron colliders, including the contributions of squark loops. To a good approximation, these additional contributions lead to the same QCD corrections as in the case where only top and bottom quark loops are taken into account. The QCD corrections are large and increase the Higgs production cross sections significantly.

Figures (2)

• Figure 1: K factors of the cross sections $\sigma(pp\rightarrow {\cal H} + X)$ for $\hbox{tg$\beta$} = 1.5$ and 30. The solid lines include $t,b$ as well as squark contributions, the dashed lines include only the $t,b$ contributions. The common squark mass is chosen to be $m_{\tilde{Q}}=200$ GeV. We take $m_b=5$ GeV, $m_t=176$ GeV and use the next--to leading order $\alpha_s$, fixed by the world average value $\alpha_s(M_Z^2) = 0.118$bethke. The cross sections are convoluted with next--to--leading order GRV parton densities GRV. The renormalization scale $\mu$ and the factorization scale $M$ are identified with the Higgs masses.
• Figure 2: Ratio of the QCD corrected cross sections $\sigma(pp \rightarrow h + X)$ with and without squark loops for three values of $\hbox{tg$\beta$} = 1.5,3, 30$, and for $M_A=100$ GeV. The secondary axes present the corresponding Higgs masses $M_h$. The quark masses, $\alpha_s$ and the parton densities are as in Fig.1.