Nuclear Theory Seminar
Wed, Apr 26, 2017 2:00 pm - 3:30 pm
Speaker: Yong Zhao
Speaker Institution: MIT
Title: Gluon Polarization in the Proton from Lattice QCD
Abstract: The gluon polarization contribution to the proton spin is calculated for the first time from lattice QCD. Though defined to be a time-dependent observable in the infinite momentum frame, the gluon polarization can be calculated on a Euclidean lattice with the large momentum effective theory. This calculation is carried out with valence overlap fermions on 2+1 flavor domain-wall fermion gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The result shows that the gluon polarization accounts for about one half of the proton spin, which is in line with recent RHIC data analysis.