Nuclear parton distributions at next to leading order

Florian, Daniel de; Sassot, R.

doi:10.1103/physrevd.69.074028

Cited by 403 publications

(705 citation statements)

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“…[33]. In practice, RUS data (left) and for NuTeV charm production data (right) from the de Florian-Sassot [35] and HKN07 [36]parametrization. The correction is shown for individual experimental data points, versus the point label (arbitrary order).…”

Section: Treatment Of the Charm Massmentioning

confidence: 99%

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

et al. 2009

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Abstract:We use recent neutrino dimuon production data combined with a global deep-inelastic parton fit to construct a new parton set, NNPDF1.2, which includes a determination of the strange and antistrange distributions of the nucleon. The result is characterized by a faithful estimation of uncertainties thanks to the use of the NNPDF methodology, and is free of model or theoretical assumptions other than the use of NLO perturbative QCD and exact sum rules. Better control of the uncertainties of the strange and antistrange parton distributions allows us to reassess the determination of electroweak parameters from the NuTeV dimuon data. We perform a direct determination of the |V cd | and |V cs | CKM matrix elements, obtaining central values in agreement with the current global CKM fit: specifically we find |V cd | = 0.244 ± 0.019 and |V cs | = 0.96 ± 0.07. Our result for |V cs | is more precise than any previous direct determination. We also reassess the uncertainty on the NuTeV determination of sin 2 θ W through the Paschos-Wolfenstein relation: we find that the very large uncertainties in the strange valence momentum fraction are sufficient to bring the NuTeV result into complete agreement with the results from precision electroweak data.1

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Section: Treatment Of the Charm Massmentioning

confidence: 99%

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

et al. 2009

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“…This data set, especially the downward trend at p T > 5 GeV, also offers a valuable constraint for the antishadowing and EMC effects in the gluon distributions. Figure 5 also compares the NLO results from the global DGLAP analyses HKN07 [18], nDS [17] and EPS09. The main difference between these sets is the existence of the gluon antishadowing/EMC-effect structure present only in EPS09.…”

Section: Results From Eps09mentioning

confidence: 99%

“…The number of data points included in the EPS09/HKN07/nDS analyses is, correspondingly, 929/1241/420, while the obtained χ 2 per data point is, correspondingly, 0.79/1.2/0.72. The average valence and sea quark, and gluon modifications at Q 2 = 1.69 GeV 2 and Q 2 = 100 GeV 2 for Pb nucleus from the NLO HKN07 [18], nDS [17] and EPS09. From [1].…”

Section: Results From Eps09mentioning

confidence: 99%

“…The first error estimates on nPDFs were provided for the LO sets HKM [15] and HKN04 [16]. The first NLO nPDFs were given in the nDS set [17] and the first error estimates in the NLO case in the HKN07 set [18]. The latest progress was made in the EPS09 analysis [1] which includes RHIC data and now for the first time provides, in addition to the best NLO fit, 30 concrete nPDF error sets (for each A).…”

Section: Introductionmentioning

confidence: 99%

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Nuclear PDFs at NLO – status report and review of the EPS09 results

2011

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We review the current status of the global DGLAP analysis of nuclear parton distribution functions, nPDFs, focusing on the recent EPS09 analysis [1], whose output, EPS09NLO, is the best-constrained NLO nPDF set on the market. Collinear factorization is found to work very well in the kinematical region studied. With the error sets released in the EPS09 package one can compute how the nPDF-related uncertainties propagate into factorizable nuclear hard-process cross sections. A comparison with the other existing NLO nPDF sets is shown, and the BRAHMS forward-η hadron data from d+Au collisions are discussed in the light of the EPS09 nPDFs and their error sets.

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“…We use GRV98 [9,10] as the parton distribution function (PDF) of free protons. Two parameterizations of the nuclear PDFs are used: EKS [11][12][13] and nDS [14]. EKS parameterization gives the nPDF as the free proton PDF multiplied by a factor:…”

Section: Using Eks and Nds Parameterizationsmentioning

confidence: 99%

Confronting color dipole and intrinsic kT approaches in D-Y dilepton production

Betemps

Oliveira

2008

Braz. J. Phys.

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We study the Drell-Yan dilepton production in proton-nucleus collisions at RHIC energies. We use two different approaches: the usual intrinsic transverse momentum approach at NLO in the infinitum momentum frame; and the color dipole in the target rest frame. We compare both formalisms at backward rapidities (proton as a target). At forward rapidities, we use earlier results considering the nucleus in a Color Glass Condensate phase. We show qualitative agreement between the two formalisms through the nuclear modification ratio as a function of both rapidity and transverse momentum and that low-mass dileptons are relevant observables to probe nuclear effects.Keywords: Drell-Yan process; Dilepton production; Nuclear effects; Dipole frame; Infinite momentum frameIn a recent work[1], Drell-Yan dilepton production at backward rapidities in hadrons collisions was studied in the rest frame of the target, i. e., in the color dipole approach. In this work, we compare these previous results with results obtained used well know intrinsic k T approach in the infinitum momentum frame [2,3]. In this frame, the process is understood as the combination of two partons to create a virtual boson that subsequently splits in the dilepton. For dilepton mass M much smaller than the Z mass, the dominant process includes only the photon as the virtual boson. The dilepton production is of particular interest since dileptons do not interact strongly and therefore carry information about initial state effects.The kinematics used here are described now. Partons and hadrons are taken as massless, the momenta of hadrons A and B are P A and P B , and the momenta of partons are p A = x A P A and p B = x B P B (for now, partons are collinear to hadrons). The virtual photon momentum is q and q 2 = M 2 is the squared dilepton mass. The Mandelstam variables are given by: s = 2P A · P B , t = (q − P A ) 2 , and u = (q − P B ) 2 . We also define x 1 = 2P B · q/s, x 2 = 2P A · q/s, and the photon rapidity y = 1 2 ln(x 1 /x 2 ). It can be showed that:in which p T is the photon (also dilepton) transverse momentum. In IMF collinear approximation, partons are considered collinear to hadrons, without intrinsic transverse momentum. Using this framework at leading order, experimental results of transverse momentum distribution cannot be reproduced: although valid for large p T , collinear NLO p T distribution diverges at p T = 0 and is not in agreement with experiments for small p T . We consider then partonic intrinsic transverse momentum, i. e., partons are not collinear to hadrons [2,3]. The partonic distributions are change as the following prescription:In this paper, we consider h( k T ) = 1 2πb 2 exp k 2 T 2b 2 . Therefore, the cross section is given by [4,5]:In the above expression, it is included the NLO collinear double differential cross section:Using the modified minimal subtraction scheme (MS), D q (z) and D g (z) are given e.g. in Ref.[6] (C F = 4/3, T R = 1/2). The second term in the right hand side of equation 3 is calculated only from annihila...

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Nuclear parton distributions at next to leading order

Cited by 403 publications

References 23 publications

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

Nuclear PDFs at NLO – status report and review of the EPS09 results

Confronting color dipole and intrinsic kT approaches in D-Y dilepton production

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