5-11 February 2017
Hyatt Regency Chicago
America/Chicago timezone

$J/\psi$ production in p+p collisions at $\sqrt{s}$ = 500 GeV at the STAR experiment

Not scheduled
2h 30m
Hyatt Regency Chicago

Hyatt Regency Chicago

151 East Wacker Drive Chicago, Illinois, USA, 60601
Board: D17


Qian Yang (University of Science and Technology of China)


Understanding $J/\psi$ meson hadroproduction has been a long-term effort both experimentally and theoretically. However, none of the existing theoretical models can successfully describe both $J/\psi$ transverse momentum ($p_{T}$) spectrum and the polarization. Furthermore, the composition of inclusive $J/\psi$ is complicated, including direct production via gluon fusion, parton fragmentation, and feed-down from excited charmonium states and B hadrons. Measurements of $J/\psi$ production at a different beam energy can shed new lights on the understanding of different $J/\psi$ production mechanisms, and help to constrain model calculations.

We report measurements of $J/\psi$ production in p+p collisions at $\sqrt{s}$ = 500 GeV in both the di-electron and di-muon channels. By combining measurements from these two channels, the $p_{T}$ spectrum of $J/\psi$ is measured from 0 to 20 GeV/$c$ and compared with NLO NRQCD and CGC+NRQCD calculations at different kinematic ranges. Feed-down contributions from $\psi(2S)$ is studied in the $p_{T}$ range of $4 < p_{T} < 12$ GeV/$c$. In addition, measurements of the $J/\psi$ production as a function of charged-particle multiplicity will be presented. A strong increase of the relative $J/\psi$ yield with multiplicity is observed for all $p_{T}$ bins with significant $p_{T}$ dependence. The results are compared with predications from the Percolation model and PYTHIA8

Preferred Track Quarkonia
Collaboration STAR

Primary author

Qian Yang (University of Science and Technology of China)

Presentation materials

There are no materials yet.