title: Probing gluonic spin-orbit correlations in photon pair production.
abstract: We consider photon pair production in hadronic collisions at large mass and small transverse momentum of the pair, assuming that factorization in terms of transverse-momentum dependent parton distributions applies. The unpolarized cross section is found to have azimuthal angular dependencies that are generated by a gluonic version of the Boer-Mulders function. In addition, the single transversely polarized cross section is sensitive to the gluon Sivers function. We present simple numerical estimates for the Boer-Mulders and Sivers effects in diphoton production at RHIC and find that the process would offer unique opportunities for exploring transverse-momentum dependent gluon distributions.
authors: Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Jian-Wei
authors: JW
authors: Qiu
authors: Marc
authors: M
authors: Schlegel
authors: Werner
authors: W
authors: Vogelsang