QCD corrections to J/psi and Upsilon production at hadron colliders

TL;DR

The cross section for hadroproduction of a pair of heavy quarks in a (3)S(1) color-singlet state at next-to-leading order in QCD corresponds to the leading contribution in the nonrelativistic QCD expansion for J/psi and Upsilon production.

Abstract

We calculate the cross section for hadroproduction of a pair of heavy quarks in a 3S1 color-singlet state at next-to-leading order in QCD. This corresponds to the leading contribution in the NRQCD expansion for J/psi and Upsilon production. The higher-order corrections have a large impact on the p_T distributions, enhancing the production at high p_T both at the Tevatron and at the LHC. The total decay rate of a 3S1 into hadrons at NLO is also computed, confirming for the first time the result obtained by Mackenzie and Lepage in 1981.

Figures (5)

• Figure 1: Representative Feynman diagrams for $^3S_1^{[1]}$ hadroproduction at LO (a), virtual (b), and real (c) contributions at NLO. Amplitudes with a light quark line (not shown) also contribute to the real corrections.
• Figure 2: Variation of the cross section for direct $\Upsilon$ production at the Tevatron (lower curves) and the LHC (upper curves) at LO (dashes) and NLO (solid). Renormalization and factorization scales are set equal, $\mu_F=\mu_R$, and $\mu_0=\sqrt{(2 m_b)^2+p_T^2}$.
• Figure 3: Variation of the cross section for direct $J/\psi$ production at the Tevatron (lower curves) and the LHC (upper curves) at LO (dashes) and NLO (solid). Renormalization and factorization scales are set equal $\mu_F=\mu_R$, and $\mu_0=\sqrt{(2 m_c)^2+p_T^2}$.
• Figure 4: Differential cross sections for direct $\Upsilon$ production via a $^3S_1^{[1]}$ intermediate state, at the Tevatron (lower histograms) and LHC (upper histograms), at LO (dashes) and NLO (solid). $p_T^{\Upsilon}>3$ GeV and $|y^{\Upsilon}|<3$. Details on the input parameters are given in the text.
• Figure 5: Differential cross sections for direct $J/\psi$ production via a $^3S_1^{[1]}$ intermediate state, at the Tevatron (lower histograms) and LHC (upper histograms), at LO (dashes) and NLO (solid). $p_T^{J/\psi}>3$ GeV and $|y^{J/\psi}|<3$. Details on the input parameters are given in the text.