Hua-Sheng Shao

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With nonrelativistic QCD factorization, we present a full next-to-leading order computation of the polarization observable for J/ψ production at hadron colliders including all important Fock states, i.e., 3S(1)([1,8]), 1S(0)([8]), and 3P(J)([8]). We find the 3P(J)([8]) channel contributes a positive longitudinal component and a negative transverse(More)
We proceed for the first time to the evaluation of the Born cross section for J / ψ + η(c) production, namely, via g + g → J/ψ+ η(c) + g, and show that it has a harder P(T) spectrum than the J/ψ-pair yield at the Born level. If one stuck to a comparison at the Born level, one would conclude that J / ψ + η(c) production would surpass that of J / ψ + J / ψ at(More)
We present an upgraded version (denoted as version 2.0) of the program HELAC-Onia for the automated computation of heavy-quarkonium helicity amplitudes within non-relativistic QCD framework. The new code has been designed to include many new and useful features for practical phenomenological simulations. It is designed for job submissions under cluster(More)
Based on Monte Carlo techniques, we analyze the initial state radiation (ISR) effects in prompt J/ψ inclusive production at B factories. ISR enhances cross section σ(e−e+ → J/ψ+gg+X) by about 15–25%, which is almost the same size as the QCD and relativistic correction. Moreover, ISR slightly changes σ(e−e+ → J/ψ+ cc̄+X). The J/ψ momentum spectrum in e−e+ →(More)
Prompt χc production at hadron colliders may provide a unique test for the color-octet mechanism in nonrelativistic QCD. We present an analysis for the polarization observables of χc1 and χc2 at next-to-leading order in αS and propose to measure them at the LHC, which is expected to be important for testing the validity of nonrelativistic QCD.
We present a complete evaluation for the prompt η_{c} production at the LHC at next-to-leading order in α_{s} in nonrelativistic QCD. By assuming heavy-quark spin symmetry, the recently observed η_{c} production data by LHCb results in a very strong constraint on the upper bound of the color-octet long-distance matrix element ⟨O^{J/ψ}(^{1}S_{0}^{[8]})⟩ of(More)
We present the first complete study of ϒ and prompt J/ψ production from single-parton scattering, including the complete O(α_{S}^{6}) color-singlet contribution, the O(α_{S}^{2}α^{2}) electroweak contribution, and the complete nonrelativistic S-wave and P-wave color-octet contribution as well as the feeddown contribution. Our study was motivated by the(More)
Vector-like quarks are featured by a wealth of beyond the Standard Model theories and are consequently an important goal of many LHC searches for new physics. Those searches, as well as most related phenomenological studies, however, rely on predictions evaluated at the leading-order accuracy in QCD and consider well-defined simplified benchmark scenarios.(More)
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