Abstract
A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when the proton momentum Pz is very large. Since taking the Pz→∞ limit is not feasible in lattice simulations, it is essential to provide guidance for which values of Pz the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution f1, helicity distribution g1, and transversity distribution h1). We find that, for intermediate parton momentum fractions x, quasi-PDFs are good approximations to standard PDFs (within 20-30%) when Pz≥1.5-2 GeV. On the other hand, for large x~1 much larger Pz>4 GeV is necessary to obtain a satisfactory agreement between the two sets. We further test the Soffer positivity bound, and find that it does not hold in general for quasi-PDFs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 112-120 |
| Number of pages | 9 |
| Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
| Volume | 743 |
| DOIs | |
| State | Published - Apr 9 2015 |
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All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
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Quasi-parton distribution functions : A study in the diquark spectator model. / Gamberg, Leonard; Kang, Zhong Bo; Vitev, Ivan; Xing, Hongxi.
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol. 743, 09.04.2015, p. 112-120.Research output: Contribution to journal › Article
TY - JOUR
T1 - Quasi-parton distribution functions
T2 - A study in the diquark spectator model
AU - Gamberg, Leonard
AU - Kang, Zhong Bo
AU - Vitev, Ivan
AU - Xing, Hongxi
PY - 2015/4/9
Y1 - 2015/4/9
N2 - A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when the proton momentum Pz is very large. Since taking the Pz→∞ limit is not feasible in lattice simulations, it is essential to provide guidance for which values of Pz the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution f1, helicity distribution g1, and transversity distribution h1). We find that, for intermediate parton momentum fractions x, quasi-PDFs are good approximations to standard PDFs (within 20-30%) when Pz≥1.5-2 GeV. On the other hand, for large x~1 much larger Pz>4 GeV is necessary to obtain a satisfactory agreement between the two sets. We further test the Soffer positivity bound, and find that it does not hold in general for quasi-PDFs.
AB - A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when the proton momentum Pz is very large. Since taking the Pz→∞ limit is not feasible in lattice simulations, it is essential to provide guidance for which values of Pz the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution f1, helicity distribution g1, and transversity distribution h1). We find that, for intermediate parton momentum fractions x, quasi-PDFs are good approximations to standard PDFs (within 20-30%) when Pz≥1.5-2 GeV. On the other hand, for large x~1 much larger Pz>4 GeV is necessary to obtain a satisfactory agreement between the two sets. We further test the Soffer positivity bound, and find that it does not hold in general for quasi-PDFs.
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U2 - 10.1016/j.physletb.2015.02.021
DO - 10.1016/j.physletb.2015.02.021
M3 - Article
AN - SCOPUS:84923320704
VL - 743
SP - 112
EP - 120
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
ER -