This title appears in the Scientific Report :
2019
Please use the identifier:
http://hdl.handle.net/2128/21169 in citations.
Quark orbital angular momentum in the proton evaluated using a direct derivative method
Quark orbital angular momentum in the proton evaluated using a direct derivative method
Quark orbital angular momentum (OAM) in the proton can be calculated directly given a Wigner function encoding the simultaneous distribution of quark transverse positions and momenta. This distribution can be accessed via proton matrix elements of a quark bilocal operator (the separation in which is...
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Personal Name(s): | Engelhardt, M. (Corresponding author) |
---|---|
Green, J. / Hasan, N. / Krieg, S. / Meinel, S. / Negele, J. / Pochinsky, A. / Syritsyn, S. | |
Contributing Institute: |
Jülich Supercomputing Center; JSC |
Imprint: |
Trieste
SISSA
2019
|
Physical Description: |
7 p. |
Conference: | 36th Annual International Symposium on Lattice Field Theory, East Lansing, Michigan (USA), 2018-07-22 - 2018-07-28 |
Document Type: |
Contribution to a book Contribution to a conference proceedings Report |
Research Program: |
Computational Science and Mathematical Methods |
Series Title: |
Proceedings of Science
LATTICE2018 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Quark orbital angular momentum (OAM) in the proton can be calculated directly given a Wigner function encoding the simultaneous distribution of quark transverse positions and momenta. This distribution can be accessed via proton matrix elements of a quark bilocal operator (the separation in which is Fourier conjugate to the quark momentum) featuring a momentum transfer (which is Fourier conjugate to the quark position). To generate the weighting by quark transverse position needed to calculate OAM, a derivative with respect to momentum transfer is consequently required. This derivative is evaluated using a direct derivative method, i.e., a method in which the momentum derivative of a correlator is directly sampled in the lattice calculation, as opposed to extracting it a posteriori from the numerical correlator data. The method removes the bias stemming from estimating the derivative a posteriori that was seen to afflict a previous exploratory calculation. Data for Ji OAM generated on a clover ensemble at pion mass $m_{\pi } = 317\, \mbox{MeV} $ are seen to agree with the result obtained via the traditional Ji sum rule method. By varying the gauge connection in the quark bilocal operator, also Jaffe-Manohar OAM is extracted, and seen to be enhanced significantly compared to Ji OAM. |