Analytical approaches to the determination of spin-dependent parton distribution functions at NNLO approximation

Salajegheh, Maral; Nejad, S. Mohammad Moosavi; Khanpour, Hamzeh; Tehrani, S. Atashbar

doi:10.1103/physrevc.97.055201

Cited by 28 publications

(11 citation statements)

References 126 publications

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“…Since that time, along with the studies of unpolarized parton distribution functions (PDFs), many experimental, theoretical and phenomenological investigations have been performed to understand the constituents of the proton's spin and also determine their distributions. In this regard, the determination of polarized PDFs (PPDFs), which describe the structure of a nucleon in a helicity eigenstate, by performing a global analysis of available experimental data has also been of great interest [2][3][4][5][6][7][8][9][10][11][12][13]. On the other hand, the structure of nucleon both in unpolarized and polarized cases can be investigated in more detail using generalized parton distributions (GPDs) [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] which comprise important concepts of Quantum Chromodynamics (QCD).…”

Section: Introductionmentioning

confidence: 99%

Nucleon axial form factor from generalized parton distributions

2019

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It is well established that the nucleon form factors can be related to Generalized Parton Distributions (GPDs) through sum-rules. On the other hand, GPDs can be expressed in terms of Parton Distribution Functions (PDFs) according to Diehl's model. In this work, we use this model to calculate polarized GPDs for quarks ( Hq) using the available polarized PDFs obtained from the experimental data, and then study the axial form factor of nucleon. We determine parameters of the model using standard χ 2 analysis of experimental data. It is shown that some parameters should be readjusted, as compared to some previously reported values, to obtain better consistency between the theoretical predictions and experimental data. Moreover, we study in details the uncertainty of nucleon axial form factor due to various sources.

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Section: Introductionmentioning

confidence: 99%

Nucleon axial form factor from generalized parton distributions

2019

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“…More details can be found in Refs. [62][63][64][65][66][67]. According to the fit procedure which will be presented in Sec.…”

Section: Technical Detail Of Qcd Analysismentioning

confidence: 99%

Improved determination of strange distribution function from the global analysis using BHPS model

Salajegheh,

Nejad,

Tehrani

2021

Preprint

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We study the impact of intrinsic strange (IS) component of nucleon sea on the global analysis of parton distribution functions (PDFs) considering a wide range of experimental data. To this aim, we consider two scenarios on the basis of BHPS model results for the IS distribution. In the first scenario, we apply the results presented through the BHPS model and in the second scenario we use its evolved distributions. For each scenarios, we present the limit of the IS probability P ss 5 for the standard tolerance criteria ∆χ 2 = 1 and 18.112 at 1σ and 4σ levels. Our results show that the experimental data can tolerate an IS component with a greater probability P ss 5 if one employs the second scenario. We obtain P ss 5 ≈ 0.01 and P ss 5 ≈ 0.025 for ∆χ 2 = 1 and 18.112, respectively, at the 4σ level. We also calculate the ratio of strange-to-light sea-quark densities rs in the proton both including and excluding the IS component. Our results show that one can obtain a higher value for the ratio rs if the IS component is included.

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“…It is well known now that the factorisation theorem of Quantum Chromodynamics (QCD) [1,2] can provide a powerful tool for calculating cross sections of high energy processes, by dividing them to perturbative and nonperturbative parts. In this respect, the nonperturbative objects such as the parton distribution functions (PDFs) [3,4,5,6,7,8,9,10,11,12,13], polarized PDFs [14,15,16,17,18,19,20], nuclear PDFs [21,22,23,24,25], and fragmentation functions (FFs) [26,27,28,29] play an essential role for testing QCD, describing the experimental data, and searching New Physics. Among them, the PDFs have always been of particular importance.…”

Section: Introductionmentioning

confidence: 99%

Study of the s−s¯ asymmetry in the proton

Goharipour

2018

Nuclear Physics A

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The study of s −s asymmetry is essential to better understand of the structure of nucleon and also the perturbative and nonperturbative mechanisms for sea quark generation. Actually, the nature and dynamical origins of this asymmetry have always been an interesting subject to research both experimentally and theoretically. One of the most powerful models can lead to s−s asymmetry is the meson-baryon model (MBM). In this work, using a simplified configuration of this model suggested by Pumplin, we calculate the s −s asymmetry for different values of cutoff parameter Λ, to study the dependence of model to this parameter and also to estimate the theoretical uncertainty imposed on the results due to its uncertainty. Then, we study the evolution of distributions obtained both at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) using different evolution schemes. It is shown that the evolution of the intrinsic quark distributions from a low initial scale, as suggested by Chang and Pang, is not a good choice at NNLO using variable flavor number scheme (VFNS).

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Analytical approaches to the determination of spin-dependent parton distribution functions at NNLO approximation

Cited by 28 publications

References 126 publications

Nucleon axial form factor from generalized parton distributions

Nucleon axial form factor from generalized parton distributions

Improved determination of strange distribution function from the global analysis using BHPS model

Study of the s−s¯ asymmetry in the proton

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