Accessing generalized TMDs through double Drell-Yan and double $\eta_c$ production processes

Abstract

Being the "mother distributions" of all types of two-parton correlation functions, generalized TMDs (GTMDs) have garnered a lot of attention. We address the important question of how to access GTMDs in physical processes. Recently, we have shown that quark GTMDs can in principle be probed through the exclusive pion-nucleon double Drell-Yan process, where the focus was on two particular GTMDs only. We now present new results concerning access to the remaining quark GTMDs in the same process. Moreover, we show that GTMDs for gluons can be explored via exclusive double production of pseudoscalar quarkonia (η c or η b ) in nucleon-nucleon collisions.

Probing the Gluon Sivers Function with an Unpolarized Target: GTMD Distributions and the Odderons

“…In this section, we clarify the relation between the Odderon amplitude and gluon GTMD distributions. The general parametrization of dipole-type gluon GTMDs can be easily adapted from the quark case [17] and reads [19…”

Hadron Tomography by Three-Dimensional Structure Functions

“…Nonetheless, the physics of phase-space distributions is very rich and one can try to select certain situations where a semiclassical interpretation is still possible. Currently, the best hope to access the GTMDs is in the low-x regime for the gluon contribution [58][59][60][61][62][63], while a single process has been identified sofar for the quark sector [64].…”