Twist-three cross-sections in deeply virtual Compton scattering

Guo, Yuxun; Ji, Xiangdong; Kriesten, Brandon; Shiells, Kyle

doi:10.1007/jhep06(2022)096

Cited by 6 publications

(3 citation statements)

References 81 publications

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“…Although this could be improved with more sets of model ansatz, it would also require more off-forward inputs accordingly. As for the off-forward fit, the main challenge seems to be the potential higher-twist effects in the JLab DVCS measurements given that the typical Q 2 of them is around 4 GeV 2 , which still allows sizeable twist-three contributions or even twist-four contributions, especially at large momentum transfer [12,58,59]. For instance, the LU cross-section plot at the lower-right of figure 2 still deviates from a perfect sine shape as predicted in the Q 2 → ∞ limit, which could be due to the higher-twist effects.…”

Section: Basics Of the Fitmentioning

confidence: 99%

Generalized parton distributions through universal moment parameterization: non-zero skewness case

Guo

Santiago³

et al. 2023

J. High Energ. Phys.

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We present the first global analysis of generalized parton distributions (GPDs) combing lattice quantum chromodynamics (QCD) calculations and experiment measurements including global parton distribution functions (PDFs), form factors (FFs) and deeply virtual Compton scattering (DVCS) measurements. Following the previous work where we parameterize GPDs in terms of their moments, we extend the framework to allow for the global analysis at non-zero skewness. Together with the constraints at zero skewness, we fit GPDs to global DVCS measurements from both the recent JLab and the earlier Hadron-Electron Ring Accelerator (HERA) experiments with two active quark flavors and leading order QCD evolution. With certain choices of empirical constraints, both sea and valence quark distributions are extracted with the combined inputs, and we present the quark distributions in the proton correspondingly. We also discuss how to extend the framework to accommodate more off-forward constraints beyond the small ξ expansion, especially the lattice calculated GPDs.

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Section: Basics Of the Fitmentioning

confidence: 99%

Generalized parton distributions through universal moment parameterization: non-zero skewness case

Guo

Santiago³

et al. 2023

J. High Energ. Phys.

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“…Therefore, we advocate an attempt to estimate the approximate size of these genuine twist-3 contributions to the cross section and they must be regarded as an additional source of uncertainty towards the extraction of the twist-2 CFFs. We have performed a full calculation of the twist-3 DVCS cross section [65], and leave its impact on the extraction of twist-2 CFFs to a future study.…”

Section: Jhep08(2022)048mentioning

confidence: 99%

On extraction of twist-two Compton form factors from DVCS observables through harmonic analysis

Shiells¹,

Guo

2022

J. High Energ. Phys.

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We investigate the exercise of locally extracting the real and imaginary parts of the four twist-2 Compton form factors (CFFs) $$ \left\{\mathcal{H},\mathcal{E},\overset{\sim }{\mathcal{H}},\overset{\sim }{\mathcal{E}}\right\} $$ H E H ~ E ~ which arise in the deeply virtual Compton scattering (DVCS) process e + p → e + p + γ. Neglecting dynamical higher-twist contributions, we find that there are a sufficient number of DVCS observables and degrees of freedom to extract all 8 leading quantities model-independently, exploiting the azimuthal dependence of the absolute cross sections across all possible beam and target polarizations at a common kinematical point in {Q, t, xB, y}. As an example, for typical JLab lab-frame kinematics, we simplify the reduced DVCS observables to their dominant terms, providing a sufficient number of equations for local determination of the twist-2 CFFs. We demonstrate the feasibility using harmonic fitting to both cross sections and beam spin asymmetries with both real and pseudo-data.

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“…The interaction of photons with matter can be described by the photoelectric effect, Compton scattering, and pair production [21][22][23]. In the photoelectric effect, a photon is absorbed by an atom or molecule, and an electron is ejected from the atom or molecule.…”

Section: Introductionmentioning

confidence: 99%

Shielding Characteristics of Polydimethylsiloxane Reinforced with Iron for Radiation Protection

Yazdankish

2024

Preprint

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This study investigates the radiation shielding properties of Polydimethylsiloxane reinforced with iron in weight fractions ranging from 5–40%. The density of the composite material was calculated using a formula that considers the densities of Polydimethylsiloxane and iron. The mass attenuation coefficient, linear attenuation coefficient, half-value layer, effective atomic number, and equivalent atomic number were calculated using the WinXCom program. The results indicate that the mass attenuation coefficient and linear attenuation coefficient values are higher for low-energy photons, and the composites reinforced with higher weights of iron display higher mass attenuation and linear attenuation coefficients. The contribution of Compton scattering remained almost constant across the energy range, while the photoelectric effect dominated at low energies, and pair production became increasingly dominant at higher energies. The half-value layer decreased as the weight fraction of iron in the composite increased, making composites with a higher weight fraction of iron more efficient at attenuating radiation to a certain level. The effective atomic number and equivalent atomic number values were also higher for composites with a higher weight fraction of iron, indicating that they are more effective at attenuating radiation. Overall, Polydimethylsiloxane reinforced with iron shows promise as a material for radiation shielding applications.

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Twist-three cross-sections in deeply virtual Compton scattering

Cited by 6 publications

References 81 publications

Generalized parton distributions through universal moment parameterization: non-zero skewness case

Generalized parton distributions through universal moment parameterization: non-zero skewness case

On extraction of twist-two Compton form factors from DVCS observables through harmonic analysis

Shielding Characteristics of Polydimethylsiloxane Reinforced with Iron for Radiation Protection

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