Systematic study of the J/ψ polarization effects on the measurement of nuclear modification factor

Te-Chuan Huang^1*, Chun-Wei Su¹, Yi Yang¹

¹Department of Physics, National Cheng Kung University, Tainan City, Taiwan

* Presenter:Te-Chuan Huang, email:tchuang@phys.ncku.edu.tw

Heavy quarkonium is one of the key candidates to study the fundamental properties of Quark-Gluon Plasma (QGP) created in heavy-ion collisions. Comparing the production of the J/ψ meson in p+p and A+A collisions, namely the nuclear modification factor (R_AA), provides the quantitative understanding of the QGP. Traditionally, the R_AA is measured under the assumption that the quarkonium is unpolarized in both p+p and A+A collisions. However, the recent measurements on the J/ψ polarization in heavy-ion collisions from the ALICE collaboration suggests that the J/ψ meson has small but non-negligible transverse polarization in the helicity frame.

In this talk, we will present the effects of the J/ψ polarization on the measurement of R_AA in the forward region using the available data from the ALICE and LHCb experiments and demonstrate the maximum effect from polarization in the central region in LHC and RHIC energies.

Keywords: Quarkonium production, Polarization, Heavy-ion collisions, Heavy flavor, J/psi meson