Speaker
Description
We study relativistic corrections to prompt $\psi(2S)$ and $J/\psi$ at high $P_T$ in hadron colliders. Our calculation employs leading-power factorization with Fragmentation Functions (FFs) computed in nonrelativistic QCD and evolved to next-to-leading-logarithmic accuracy. We extract constraints on the $\chi_c$ feeddown to the $J/\psi$ yield from the measured $\psi(2S)/J/\psi$ yield ratio. Relativistic corrections increase the cross section significantly for the gluon channel, but moderately for charm. We perform a full analysis of uncertainties. We observe a good agreement with both ATLAS and CMS cross sections without the need of higher-order color-octet contributions. The polar anisotropy is found to be close to CMS data, partly due to charm fragmentation. Implications for the EIC quarkonium-physics case are discussed.