[RBRC seminar] Gluon Sivers function from forward exclusive photo-production of chi_c1 quarkonium in UPCs or at the EIC

by Prof. Adrian Dumitru (Baruch college)

Thursday 9 Jan 2025, 12:30 → 14:30 US/Eastern

2-160 (https://bnl.zoomgov.com/j/1600983728?pwd=RAD7OLcqre7Ycsp6JfFp6HAnpyLxex.1)

In PRL 124 (2020) p.17, Boussarie et al argued that forward
*exclusive* production of C=+ mesons in DIS provides access to the
gluon Sivers TMD. We consider photo-production of axial-vector chi_c1
quarkonium where the Coulomb singularity at t-->0 is screened thanks
to the Landau-Yang theorem. We relate the cross section for this
process to the tri-gluon correlation function O(x,x), and finally to
the PDF given by the kT^2 moment of the gluon Sivers TMD. The C-odd
gluon exchange process, unlike the Primakoff background, produces
longitudinally polarized chi_c1, and we present numerical predictions
for the effective polarization lambda_theta as a function of x below
x~0.1.