Drell-Yan processes, transversity, and light-cone wave functions

Abstract

The unpolarized, helicity and transversity distributions of quarks in the proton are calculated in the overlap representation of light-cone wavefunctions truncated to the lowest order Fock-space components with three valence quarks. The three distributions at the hadronic scale satisfy an interesting relation consistent with the Soffer inequality. Results are derived in a relativistic quark model including evolution up to the next-to-leading order. Predictions for the double transverse-spin asymmetry in Drell-Yan dilepton production initiated by proton-antiproton collisions are presented. Asymmetries of about 20-30% are found in the kinematic conditions of the PAX experiment.

Simultaneous extraction of transversity and Collins functions from new semi-inclusive deep inelastic scattering ande+e−data

“…[8] (number 10) and computed with lattice [28] (number 5) or model calculations Refs. [26,27,[29][30][31][32](respectively, numbers 3, 4 and 6-9).…”

Modelling the nucleon structure

“…A different approach consists in a direct calculation of GPDs using effective quark models. After the first calculation within the MIT bag model [103], GPDs were calculated in the χQSM [104][105][106][107][108][109][110], using covariant BetheSalpeter approaches [111][112][113][114][115][116][117][118], in the quark-target model [51,119,120], in nonrelativistic quark models [121][122][123], in light-front quark models [7,[124][125][126][127][128], in meson-cloud models [129,130], and from LFWFs inspired by AdS/QCD [131][132][133]. Although these models single out only a few features of the QCD dynamics in hadrons, they may provide some guidance on the functional dependence of GPDs, particularly if a model is constrained to reproduce electromagnetic form factors and ordinary parton distributions.…”

Pion transverse momentum dependent parton distributions in a light-front constituent approach, and the Boer-Mulders effect in the pion-induced Drell-Yan process

“…We will refer to this approach as the light-front constituent model (LFCM). The LFCM was successfully applied to describe many nucleon properties [51][52][53][54][55][56][57][58][59][60] including TMDs [61][62][63][64]. For the pion, the specific model we will adopt for the minimal Fock-space components of the LFWF has been originally proposed in Refs.…”