Moments of proton GPDs from the OPE of nonlocal quark bilinears up to NNLO

Bhattacharya, S.; Cichy, Krzysztof; Constantinou, Martha; Xiang, Gao; Metz, Andreas; Miller, Joshua D.; Mukherjee, Swagato; Petreczky, Péter; Steffens, Fernanda; Zhao, Yong

doi:10.1103/physrevd.108.014507

Cited by 15 publications

(6 citation statements)

References 150 publications

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“…In the past decade, the DDIS process has been widely used to study the proton shape [4, 5, 28−34]. Based on the constituent quark picture of the proton, several hot spot models have been proposed to describe the proton shape in the exclusive DDIS [5,31,32,35], where the hot spot is actually a gluon formed by the emission from a large x valence quark. At high energy, it has been found that the proton is not a spherical object; it consists of several hot spots and its shape fluctuates event-by-event [3].…”

Section: Dσ/dtmentioning

confidence: 99%

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Probing valence quark width of the proton in deeply virtual Compton scattering at high energies*

Xiang 向,

Cao 曹,

Zhou 周

2024

Chinese Phys. C

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We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the framework of Color Glass Condensate. To investigate the individual valence quark shape, a novel treatment of the valence quark width is employed. We calculate the cross-sections for the coherent and incoherent deeply virtual Compton scattering, for the first time, by using different widths ($\mathrm{B_u}$ and $\mathrm{B_d}$) for the profile density distributions of the up and down quarks instead of using the same width as in the literature. We find that the cross-sections calculated with $\mathrm{B_u \geq B_d}$ at each collision energy are consistent with each other themselves, which is in agreement with the theoretical expectations. While the ones computed with $\mathrm{B_u < B_d}$ show some discrepancies. This outcome implies that the up quark might emit more gluons than the down quark leading to $\mathrm{B_u \geq B_d}$ at high energy. The energy impact of the outcome is estimated. Our results show that as the collision energy increases, the aforementioned discrepancies are not only significantly broadened, but also shift to relatively smaller momentum transfer range in the future Electron-Ion Collider (EIC) and Large Hadron Electron Collider (LHeC) energies, which indicates that the EIC and LHeC can provide unprecedented chance to access the shape of the valence quark of the proton.

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Section: Dσ/dtmentioning

confidence: 99%

“…Therefore, the log-normal distribution must be normalized to maintain the desired expectation. Note that a recent study demonstrated that saturation scale fluctuations can be interpreted as fluctuations in dipole size [35].…”

Section: Saturation Scale and Geometric Fluctuations J/ψmentioning

confidence: 99%

Probing valence quark width of the proton in deeply virtual Compton scattering at high energies*

Xiang 向,

Cao 曹,

Zhou 周

2024

Chinese Phys. C

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“…Figure 6: The fifth moments A 50 and B 50 derived from SDF approach for iso-vector (upper panels) and iso-scalar (lower panels) nucleon unpolarized GPDs from Ref. [60] are shown as a function of −t. The results using traditional local operator methods from ETMC [61] are also shown for comparison.…”

Section: Xiang Gaomentioning

confidence: 99%

“…Recently, progress was made in Ref. [58,59]. It was shown that through Lorentz covariant parameterization of the matrix elements in terms of Lorentz-invariant amplitudes, matrix elements in different frames can be related to each other.…”

Section: Xiang Gaomentioning

confidence: 99%

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Overview of hadron structure from lattice QCD

Gao

2024

Proceedings of the 40th International Symposium on Lattice Field Theory — PoS(LATTICE2023)

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We review the latest progress in lattice QCD calculations of the hadron structure. There have been improved calculations of form factors and gravitational form factors by removing the lattice artifacts. Additionally, we highlight the rapid development in lattice calculations of x-dependent parton distributions. This area of study has expanded from various one-dimensional parton distribution functions (PDFs) to three-dimensional distributions like generalized parton distribution functions (GPDs) and transverse-momentum-dependent PDFs (TMDs). These advancements are being achieved within the large momentum effective theory (LaMET) framework and similar methodologies, with considerable progress in controlling lattice artifacts as well as enhancing theoretical accuracy.

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Evolution of parton distribution functions in the short-distance factorization scheme

Dutrieux,

Karpie,

Monahan

et al. 2024

J. High Energ. Phys.

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Lattice QCD offers the possibility of computing parton distributions from first principles, although not in the usual $$ \overline{MS} $$ MS ¯ factorization scheme. Calculations are therefore matched to $$ \overline{MS} $$ MS ¯ using a perturbative procedure which is the source of significant uncertainty within the currently accessible kinematics. We present the possibility of computing the z2 evolution of non-singlet pseudo-parton distribution functions within the short factorization scheme in a numerically improvable way. The goal is to have tools to evolve a calculation to a scale where perturbative uncertainties are less pronounced. We compare a numerical extraction of the evolution operator from lattice data to the computation of z2 dependence in perturbation theory. Finally, we discuss how this numerical work may be extended to address the two-scale problem that arises when the Ioffe time range must be made large to extend the reach of the calculation of the pseudo-PDF to smaller values of the momentum fraction.

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Moments of proton GPDs from the OPE of nonlocal quark bilinears up to NNLO

Cited by 15 publications

References 150 publications

Probing valence quark width of the proton in deeply virtual Compton scattering at high energies*

Probing valence quark width of the proton in deeply virtual Compton scattering at high energies*

Overview of hadron structure from lattice QCD

Evolution of parton distribution functions in the short-distance factorization scheme

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