GPDs AND TMDs

2012 ◽  
Vol 20 ◽  
pp. 75-83
Author(s):  
MATTHIAS BURKARDT
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Transverse Plane ◽  
Final State ◽  
Parton Distributions ◽  
Generalized Parton Distributions ◽  
Wigner Distributions ◽  
Quark Orbital Angular Momentum ◽  
Final State Interactions ◽  
The Difference

For transversely polarized nucleons the distribution of quarks in the transverse plane is transversely shifted and that shift can be described in terms of Generalized Parton Distributions (GPDs). This observation provides a 'partonic' derivation of the Ji-relation for the quark angular momentum in terms of GPDs. Wigner distributions are used to show that the difference between the Jaffe-Manohar definiton of quark orbital angular momentum and that of Ji is equal to the change of orbital angular momentum due to the final state interactions as the struck quark leaves the target in a DIS experiment.

scholarly journals Quark Orbital Angular Momentum and Final State Interactions

2015 ◽  
Vol 37 ◽  
pp. 1560035 ◽  
Author(s):  
Matthias Burkardt
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Final State ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Wigner Distributions ◽  
Single Spin Asymmetries ◽  
Quark Orbital Angular Momentum ◽  
The Difference ◽  
Definition Of

Definitions of orbital angular momentum based on Wigner distributions are used to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. The difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

scholarly journals QUARK ORBITAL ANGULAR MOMENTUM AND FINAL STATE INTERACTIONS

2014 ◽  
Vol 25 ◽  
pp. 1460029 ◽  
Author(s):  
MATTHIAS BURKARDT
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Final State ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Wigner Distributions ◽  
Single Spin Asymmetries ◽  
Quark Orbital Angular Momentum ◽  
The Difference ◽  
Definition Of

Definitions of orbital angular momentum based on Wigner distributions are used to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. The difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

scholarly journals WIGNER DISTRIBUTIONS AND QUARK ORBITAL ANGULAR MOMENTUM

2012 ◽  
Vol 20 ◽  
pp. 84-91 ◽  
Author(s):  
CÉDRIC LORCÉ ◽  
BARBARA PASQUINI
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
Generalized Parton Distributions ◽  
Wigner Distributions ◽  
Quark Orbital Angular Momentum ◽  
Quark Phase

We discuss the quark phase-space or Wigner distributions of the nucleon which combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. In particular, we present results for the distribution of unpolarized quarks in a longitudinally polarized nucleon obtained in a light-front constituent quark model. We show how the quark orbital angular momentum can be extracted from the Wigner distributions and compare it with alternative definitions.

QUARK ORBITAL ANGULAR MOMENTUM AND GENERALIZED PARTON DISTRIBUTIONS

2003 ◽  
Vol 18 (08) ◽  
pp. 1303-1309 ◽  
Author(s):  
XIANGDONG JI
Keyword(s):  
Angular Momentum ◽  
Quantum Chromodynamics ◽  
Orbital Angular Momentum ◽  
Parton Distributions ◽  
Generalized Parton Distributions ◽  
Quark Orbital Angular Momentum

In this talk, I review the merit of introducing and measuring the quark orbital angular momentum contribution to the spin of the nucleon in the context of quantum chromodynamics.

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).

PARTONIC PICTURE OF GTMDS

2014 ◽  
Vol 25 ◽  
pp. 1460009 ◽  
Author(s):  
SIMONETTA LIUTI ◽  
ABHA RAJAN ◽  
AURORE COURTOY ◽  
GARY R. GOLDSTEIN ◽  
J. OSVALDO GONZALEZ HERNANDEZ
Keyword(s):  
Angular Momentum ◽  
Compton Scattering ◽  
Orbital Angular Momentum ◽  
Scattering Amplitude ◽  
Final State Interaction ◽  
Deeply Virtual Compton Scattering ◽  
Virtual Compton Scattering ◽  
Matrix Elements ◽  
Final State ◽  
Wigner Distributions

We argue that due to parity constraints, the helicity combination of the purely momentum space counterparts of the Wigner distributions — the generalized transverse momentum distributions — that describes the configuration of an unpolarized quark in a longitudinally polarized nucleon, can enter the deeply virtual Compton scattering amplitude only through matrix elements involving a final state interaction. The relevant matrix elements in turn involve light cone operators projections in the transverse direction, or they appear in the deeply virtual Compton scattering amplitude at twist three. Orbital angular momentum or the spin structure of the nucleon was a major reason for these various distributions and amplitudes to have been introduced. We show that twist three contributions to deeply virtual Compton scattering provide observables related to orbital angular momentum.

Sign in / Sign up

Export Citation Format

Share Document