TY - JOUR

T1 - Gluon and Wilson loop TMDs for hadrons of spin ≤ 1

AU - Boer, Daniel

AU - Cotogno, Sabrina

AU - van Daal, Tom

AU - Mulders, Piet J.

AU - Signori, Andrea

AU - Zhou, Ya-Jin

PY - 2016/10/4

Y1 - 2016/10/4

N2 - In this paper we consider the parametrizations of gluon transverse momentum dependent (TMD) correlators in terms of TMD parton distribution functions (PDFs). These functions, referred to as TMDs, are defined as the Fourier transforms of hadronic matrix elements of nonlocal combinations of gluon fields. The nonlocality is bridged by gauge links, which have characteristic paths (future or past pointing), giving rise to a process dependence that breaks universality. For gluons, the specific correlator with one future and one past pointing gauge link is, in the limit of small x, related to a correlator of a single Wilson loop. We present the parametrization of Wilson loop correlators in terms of Wilson loop TMDs and discuss the relation between these functions and the small-x 'dipole' gluon TMDs. This analysis shows which gluon TMDs are leading or suppressed in the small-x limit. We discuss hadronic targets that are unpolarized, vector polarized (relevant for spin-1/2 and spin-1 hadrons), and tensor polarized (relevant for spin-1 hadrons). The latter are of interest for studies with a future Electron-Ion Collider with polarized deuterons.

AB - In this paper we consider the parametrizations of gluon transverse momentum dependent (TMD) correlators in terms of TMD parton distribution functions (PDFs). These functions, referred to as TMDs, are defined as the Fourier transforms of hadronic matrix elements of nonlocal combinations of gluon fields. The nonlocality is bridged by gauge links, which have characteristic paths (future or past pointing), giving rise to a process dependence that breaks universality. For gluons, the specific correlator with one future and one past pointing gauge link is, in the limit of small x, related to a correlator of a single Wilson loop. We present the parametrization of Wilson loop correlators in terms of Wilson loop TMDs and discuss the relation between these functions and the small-x 'dipole' gluon TMDs. This analysis shows which gluon TMDs are leading or suppressed in the small-x limit. We discuss hadronic targets that are unpolarized, vector polarized (relevant for spin-1/2 and spin-1 hadrons), and tensor polarized (relevant for spin-1 hadrons). The latter are of interest for studies with a future Electron-Ion Collider with polarized deuterons.

KW - QCD Phenomenology

KW - DEEP-INELASTIC-SCATTERING

KW - DRELL-YAN PROCESS

KW - FINAL-STATE INTERACTIONS

KW - FIXED-TARGET EXPERIMENT

KW - STRUCTURE-FUNCTION G(1)

KW - TRANSVERSE-MOMENTUM

KW - SINGLE-SPIN

KW - SMALL-X

KW - QUARKONIUM PRODUCTION

KW - PARTON DISTRIBUTIONS

U2 - 10.1007/JHEP10(2016)013

DO - 10.1007/JHEP10(2016)013

M3 - Article

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1126-6708

M1 - 013

ER -