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arXiv · 1411.7350

$\eta_c$ production at LHC and indications on the understanding of $J/\psi$ production

Hao Han·Yan-Qing Ma·Ce Meng·Hua-Sheng Shao·Kuang-Ta Chao
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Abstract

We present a complete evaluation for the prompt $\eta_c$ production at the LHC at next-to-leading order in $\alpha_s$ in nonrelativistic QCD. By assuming heavy quark spin symmetry, the recently observed $\eta_c$ production data by LHCb results in a very strong constraint on the upper bound of the color-octet long distance matrix element $1S0$ of $J/\psi$. We find this upper bound is consistent with our previous study of the $J/\psi$ yield and polarization and can give good descriptions for the measurements, but inconsistent with some other theoretical estimates. This may provide important information for understanding the nonrelativistic QCD factorization formulism.

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Hao Han, Yan-Qing Ma, Ce Meng, Hua-Sheng Shao, Kuang-Ta Chao. 2014-11-26. $\eta_c$ production at LHC and indications on the understanding of $J/\psi$ production. https://doi.org/10.1103/physrevlett.114.092005

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