Back-to-back isolated photon-quarkonium production at the LHC and the transverse-momentum-dependent distributions of the gluons in the proton

Abstract

The study of a quasi back-to-back isolated pair made of a heavy quarkonium, such as a J/psi or a Upsilon, and a photon produced in proton-proton collisions at the LHC, is probably the optimal way to get right away a first experimental determination of two gluon transverse-momentum-dependent distributions (TMDs) in an unpolarized proton, f1^g and h1^perp,g the latter giving the distribution of linearly polarized gluons. To substantiate this, we calculate the transverse-momentum-dependent effects that arise in the process under study and discuss the feasibility of their measurements.

Comments: LaTeX, 6 pages, 4 figures, uses ws-ijmpcs.cls (included). Contribution to the proceedings of the 21st International Symposium on Spin Physics (SPIN2014), October 20-24, 2014, Beijing, China