The Nlo QCD Calculation of Sea Quark Distributions in the Corgi Approach, Based on the Constituent Quark Model

Mirjalili, A.; Keshavarzian, K.

doi:10.1142/s0217751x07037056

Cited by 11 publications

(8 citation statements)

References 19 publications

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“…By accessing the parton densities at initial energy scale, 2 0 , we can obtain its evolved Mellin moments with respect to different values of 2 . We plot in Figure 1 the first and second moment of parton densities versus 2 , using (15). We use the valence parton density in [14] at 2 0 = 0.34 GeV 2 as the input parton density.…”

Section: An Overview Of Parton Densities Evolution In Mellin Moment Smentioning

confidence: 99%

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Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

Mirjalili

Yazdanpanah

Moradi

2014

Advances in High Energy Physics

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Since there are not experimental data over the whole range ofx-Bjorken variable, that is,0<x<1, we are inevitable in practice to do the integration for Mellin moments over the available range of experimental data. Among the methods of analysing DIS data, there are the methods based on application of Mellin moments. We use the truncated Mellin moments rather than the usual moments to analyse the EMC collaboration data for muon-nucleon and WA25 data for neutrino-deuterium DIS scattering. How to connect the truncated Mellin moments to usual ones is discussed. Following that we combine the truncated Mellin moments with the Bernstein polynomials. As a result, Bernstein averages which are related to different orders of the truncated Mellin moment are obtained. These averaged quantities can be considered as the constructed experimental data. By accessing the sufficient experimental data we can do the fitting more precisely. We do the fitting at leading order and next-to-leading order approximations to extract the QCD cutoff parameter. The results are in good agreement with what is being expected.

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Section: An Overview Of Parton Densities Evolution In Mellin Moment Smentioning

confidence: 99%

“…Different methods exist to get the parton densities in space. One of them can be found in [15]. There are different sets of parton densities in -space.…”

Section: An Overview Of Parton Densities Evolution In Mellin Moment Smentioning

confidence: 99%

Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

Mirjalili

Yazdanpanah

Moradi

2014

Advances in High Energy Physics

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“…The moments of quark and gluon distributions at any energy scale inside the meson are obtained by multiplying the valon moments with the appropriate moments of singlet, non-singlet and gluon sectors. Using the inverse Mellin transformation in the parameterized form as described in [22] and fitting over the available experimental data, the valence quark densities inside the mesons will be obtained.…”

Section: Valon Modelmentioning

confidence: 99%

LowQ²proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework

Mirjalili

Yazdanpanah

Taghavi-Shahri

et al. 2010

J. Phys. G: Nucl. Part. Phys.

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Abstract. The idea of the meson cloud approach in the chiral quark model has been extended to include gluon cloud in order to achieve the parton densities in the nucleon, based on the constitute quark framework. The splitting function of the quark to the quark-meson and quark-gluon at low Q 2 value are used to obtain parton densities in the constituent quark. The phenomenological constituent model is employed to extract the parton distributions in the proton at low Q 2 value. Since we have access to the parton densities at low Q 2 , we are able to obtain F 2 (x, Q 2 ) structure function at low Q 2 value. The result is in good agreement with available experimental data and some theoretical models. To confirm the validity of our calculations, the fraction of total momentum of proton which is carried by gluon at high Q 2 and also the Gottfried sum rule are computed. The results are in good agreement with what are expected.

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“…(17), using Eqs. (23), (30) and (31) for mesons. Having these four parameters, we can then calculate the distributions of δM Σ (n, Q 2 ) (the moment of singlet sector of the distributions) and δM g (n, Q 2 ) (the moment of the gluon distribution):…”

Section: Valence Quark Distribution For Eta Mesonmentioning

confidence: 99%

“…(36) has been introduced in Ref. [30]. In all of the numerical methods, we simply fit the moment of a definite function (which contains free parameters) to the experimental data or the results of a known function -for example, Eqs.…”

Section: Valence Quark Distribution For Eta Mesonmentioning

confidence: 99%

Meson polarized distribution function and mass dependence of the nucleon parton densities

Mirjalili¹,

Keshavarzian²

2014

Chinese Phys. C

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The polarized distribution functions of mesons, including pion, kaon and eta, using the proton structure function, are calculated. We are looking for a relationship between the polarized distribution of mesons and the polarized structure of nucleons. We show that the meson polarized parton distributions leads to zero total spin for mesons, considering the orbital angular momentum of quarks and gluons inside the meson. Two separate Monte Carlo algorithms are applied to compute the polarized parton distributions of the kaon. Via the mass dependence of quark distributions, the distribution function of the eta meson is obtained. A new method by which the polarized sea quark distributions of protons are evolved separately -which cannot be performed easily using the standard solution of DGLAP equations -is introduced. The mass dependence of these distributions is obtained, using the renormalization group equation which makes their evolutions more precise. Comparison between the evolved distributions and the available experimental data validates the suggested solutions for separate evolutions.In Part 1, we calculate the bare quark distributions using the proton polarized structure function g p 1 (x), using data from [10]. Then we compute the ratio of the polarized valence data of kaons to that of pions, δq K val /δq π val , using the data for their unpolarized ratio, q K val /q π val [11], based on two separate Monte Carlo algorithms. We also calculate the polarized valence ratio of eta mesons to pions, δq η val /δq π val , using the mass dependence of the valence quark distribution inside the meson. Substituting these ratios into the chiral quark model (χQM) equations and fitting with experimental data (or any reasonable phenomenological model), the polarized distribution functions in pion, kaon and eta mesons at low energy scales will be obtained. Following that, the evolution of the PDFs, employing the DGLAP equations, can be done straightforwardly [12][13][14][15]. Using these evolved PDFs, we can extract the values of the orbital angular momentum of quarks and gluons inside mesons [6].In Part 2, the PPDFs of the proton, using the distributions extracted for mesons, are calculated. The valence PPDF of the proton can be evolved easily using the non-singlet moment δM NS . Since the DGLAP equations can thoroughly evolve only the sea quark distribution, however, the evolution of the separated sea quarks is more complicated. There are reasonable methods to separate the evolution of sea quarks [16] but in this work we use the running mass and renormalization equation to make the sea quark distribution functions depend on the quark masses. Thereby, the eigenvalues of the evolution operator become non-degenerate. The sea quark distributions at low scale Q 2 0 , arising from χQM , are unsymmetrized. The different eigenvalues of the evolution operator, which are obtained as a result of the new method introduced in this paper, makes the evolution of sea quark densities more distinctive than what we obtained in [17]. Two bounda...

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The Nlo QCD Calculation of Sea Quark Distributions in the Corgi Approach, Based on the Constituent Quark Model

Cited by 11 publications

References 19 publications

Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

LowQ²proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework

Meson polarized distribution function and mass dependence of the nucleon parton densities

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The Nlo QCD Calculation of Sea Quark Distributions in the Corgi Approach, Based on the Constituent Quark Model

Cited by 11 publications

References 19 publications

Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

LowQ2proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework

Meson polarized distribution function and mass dependence of the nucleon parton densities

Contact Info

Product

Resources

About

LowQ²proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework