scholarly journals Parton transverse momentum and orbital angular momentum distributions

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
Abha Rajan ◽  
Aurore Courtoy ◽  
Michael Engelhardt ◽  
Simonetta Liuti
Keyword(s):  
Angular Momentum ◽  
Transverse Momentum ◽  
Orbital Angular Momentum ◽  
Momentum Distributions

scholarly journals MEASUREMENT OF FORWARD JETS AT RHIC

2014 ◽  
Vol 25 ◽  
pp. 1460022 ◽  
Author(s):  
◽  
L. C. BLAND
Keyword(s):  
Angular Momentum ◽  
Transverse Momentum ◽  
Orbital Angular Momentum ◽  
Initial State ◽  
Spin Asymmetries ◽  
Jet Production ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Forward Jets

We present first measurements of forward jet production from p↑ + p collisions at [Formula: see text] GeV, including transverse single spin asymmetries. These asymmetries are expected to be sensitive to spin-correlated transverse momentum in the initial state, which is particularly interesting because it is related to orbital angular momentum in the proton.

Generalized TMDs

2015 ◽  
Vol 37 ◽  
pp. 1560037 ◽  
Author(s):  
Koichi Kanazawa ◽  
Cedric Lorcé ◽  
Andreas Metz ◽  
Barbara Pasquini ◽  
Marc Schlegel
Keyword(s):  
Angular Momentum ◽  
Transverse Momentum ◽  
Perturbative Qcd ◽  
Orbital Angular Momentum ◽  
Close Relation ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
Model Independent ◽  
Mere Existence

Generalized transverse-momentum dependent parton distributions (GTMDs) encode the most general parton structure of hadrons. In this contribution, which is largely based on a recent publication,1 we focus on two twist-2 GTMDs which are denoted by F1,4 and G1,1 in parts of the literature. As already shown previously, both GTMDs have a close relation to orbital angular momentum of partons inside a hadron. However, recently even the mere existence of F1,4 and G1,1 has been doubted. We explain why this claim does not hold. We support our model-independent considerations by calculating the GTMDs in two spectator models and in perturbative QCD. For the model results we also explicitly check the relation to the orbital angular momentum of partons inside hadrons.

scholarly journals Observables for Quarks and Gluons Orbital Angular Momentum Distributions

2015 ◽  
Vol 37 ◽  
pp. 1560039
Author(s):  
Simonetta Liuti ◽  
Aurore Courtoy ◽  
Gary R. Goldstein ◽  
J. Osvaldo Gonzalez Hernandez ◽  
Abha Rajan
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Spin Asymmetry ◽  
Energy Momentum Tensor ◽  
Deeply Virtual Compton Scattering ◽  
Virtual Compton Scattering ◽  
Momentum Tensor ◽  
Transverse Momentum Distribution ◽  
Kinetic Term ◽  
Momentum Distributions

We discuss the observables that have been recently put forth to describe quarks and gluons orbital angular momentum distributions. Starting from a standard parameterization of the energy momentum tensor in QCD one can single out two forms of angular momentum, a so-called kinetic term – Ji decomposition – or a canonical term – Jaffe-Manohar decomposition. Orbital angular momentum has been connected in each decomposition to a different observable, a Generalized Transverse Momentum Distribution (GTMD), for the canonical term, and a twist three Generalized Parton Distribution (GPD) for the kinetic term. While the latter appears as an azimuthal angular modulation in the longitudinal target spin asymmetry in deeply virtual Compton scattering, due to parity constraints, the GTMD associated with canonical angular momentum cannot be measured in a similar set of experiments.

Measuring the Sea Quark Sivers Asymmetry: The E1039 Experiment at Fermilab

2015 ◽  
Vol 37 ◽  
pp. 1560064
Author(s):  
Andi Klein
Keyword(s):  
Experimental Data ◽  
Angular Momentum ◽  
Transverse Momentum ◽  
Proton Beam ◽  
Orbital Angular Momentum ◽  
Nucleon Spin ◽  
Spin Direction ◽  
Sivers Function

One of the continuing puzzles in QCD is the origin of the nucleon spin. All of the existing experimental data suggest that the contributions from the quark and gluon spins account only for about 50% of the nucleon spin. In order to account for the remaining 50%, one has to include the orbital angular momentum of the quarks and gluons. One way to establish if quarks carry significant angular momentum, is to perform a measurement of the Sivers function, which describes the correlation of the spin direction of the nucleon with the transverse momentum of the quark. We will describe the E1039 experiment at Fermilab, which will measure the Sivers asymmetry of the sea quarks via the Drell-Yan process, using a 120 GeV unpolarized proton beam on a transversely polarized NH 3 target.

scholarly journals Defining the Observables for Quarks and Gluons Orbital Angular Momentum Distributions

2015 ◽  
Vol 56 (6-9) ◽  
pp. 325-330
Author(s):  
S. Liuti ◽  
A. Courtoy ◽  
G. R. Goldstein ◽  
J. O. Gonzalez Hernandez ◽  
A. Rajan
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Momentum Distributions

scholarly journals Wigner Distributions and Orbital Angular Momentum of Quarks

2015 ◽  
Vol 37 ◽  
pp. 1560040
Author(s):  
Asmita Mukherjee ◽  
Sreeraj Nair ◽  
Vikash Kumar Ojha
Keyword(s):  
Angular Momentum ◽  
Transverse Momentum ◽  
Model Calculation ◽  
Orbital Angular Momentum ◽  
Momentum Space ◽  
Recent Model ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
Generalized Parton Distributions ◽  
Wigner Distributions

We present a recent model calculation of the Wigner distributions for the quarks and the orbital angular momentum carried by the quarks. These Wigner distributions contain combined position and momentum space information of the quark distributions and are related to both generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs).

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