May 29, 2018 to June 3, 2018
Hyatt Regency Indian Wells Conference Center
US/Pacific timezone

Nuclear PDF, Small $x$ Physics Results at RHIC

May 30, 2018, 4:40 PM
North Foyer | Joshua Tree Room (Hyatt Regency Indian Wells Conference Center)

North Foyer | Joshua Tree Room

Hyatt Regency Indian Wells Conference Center

44600 Indian Wells Lane, Indian Wells, CA 92210, USA


Dr Xuan Li (Los Alamos National Lab)


The proton gluon distribution function increases rapidly with decreasing momentum fraction $x$ at fixed $Q^2$, but cannot increase indefinitely as $x$ decreases. Gluon saturation is expected at a low $x$ value when gluon recombination balances gluon splitting. The nuclear (with atomic mass number A) gluon distribution is approximately $A^{1/3}$ larger than the nucleon gluon distribution function at the same $x$. Understanding the kinematics of gluons in the low $x$ region will provide insights into the nuclear matter origin and improves the knowledge of Quantum Chromodyanmics (QCD) in the non-perturbative region. The Relativistic Heavy Ion Collider (RHIC) can probe gluons with $x$ between 0.001 and 0.02 inside the gold nuclei via forward di-jet or di-hadron measurements. Both STAR and PHENIX experiments have carried out a series of measurements to study the nuclear gluon distribution functions (nPDFs) and observed clear nuclear modification of the gluon PDF in the low $x$ region. Recent studies of forward inclusive hadron, di-hadron, di-jet and heavy flavor measurements in 200 GeV d+Au, $p$+Au, $p$+Al and $^3$He+Au collisions and 500/510 GeV $p$+$p$ collisions have extended the kinematic region of the probed proton/nuclear gluon distribution function. We will present selected results from RHIC in this talk. Prospects of future measurements from detector upgrades at PHENIX, sPHENIX and Electron Ion Collider (EIC) will be presented as well.
E-mail [email protected]
Collaboration name PHENIX
Funding source DOE Office of Science

Primary author

Dr Xuan Li (Los Alamos National Lab)

Presentation materials