EPS09: A New Generation of NLO and LO Nuclear Parton Distribution Functions

By K. Eskola, H. Paukkunen, C. Salgado. 2009

1,015 citations recorded by the source corpus.

We present a next-to-leading order (NLO) global DGLAP analysis of nuclear parton distribution functions (nPDFs) and their uncertainties. Carrying out an NLO nPDF analysis for the first time with three different types of experimental input — deep inelastic l+A scattering, Drell-Yan dilepton production in p+A collisions, and inclusive pion production in d+Au and p+p collisions at RHIC — we find that these data can well be described in a conventional collinear factorization framework. Although the pion production has not been traditionally included in the global analyses, we find that the shape of the nuclear modification factor RdAu of the pion pT-spectrum at midrapidity retains sensitivity to the gluon distributions, providing evidence for shadowing and EMC-effect in the nuclear gluons. We use the Hessian method to quantify the nPDF uncertainties which originate from the uncertainties in the data. In this method the sensitivity of χ2 to the variations of the fitting parameters is mapped out to orthogonal error sets which provide a user-friendly way to calculate how the nPDF uncertainties propagate to any factorizable nuclear cross-section. The obtained NLO and LO nPDFs and the corresponding error sets are collected in our new release called family EPS09. These results should find applications in precision analyses of the signatures and properties of QCD matter at the LHC and RHIC.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/963a65d9fea559a03853ce91fd19302a9a36966f

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Citations in the corpus

A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector (2012, methodology): “Results are shown from [326] (nDS, black dashed), [327] (HKN07, green solid), [167] (EPS09, red dotted), [329] (FGS10, blue dashed-dotted; in this case the lowest Q(2) is 4 GeV(2) and two lines are drawn reflecting the uncertainty in the predictions) and [328] (DSSZ, cyan dashed-dotted).”
Small System Collectivity in Relativistic Hadronic and Nuclear Collisions (2018, background): “Measurements in d+Au and p+Pb collisions at RHIC and the LHC have been very useful, for example, in constraining nuclear modified parton distribution functions (nPDFs) that determine the initial gluon distributions that determine the first epoch of heavy ion collisions (50, 51).”
CGC predictions for p + Pb collisions at the LHC (2012, methodology): “We compare also to Rp+Pb from collinear factorization using EPS09 nPDFs [53, 54] as well as to results from the “IP-sat” model and from an independent rcBK imple-”
New observables in inclusive production of quarkonia (2019, methodology): “Since the EMC measurement [166], we know that the parton flux inside nuclei –as encoded in nuclear PDF (nPDF)[167, 168, 169, 170, 171, 172, 173]– differs from that of in the nucleon used as references.”
A hybrid strong/weak coupling approach to jet quenching (2014, methodology): “is very small [63, 64], we simulated high energy jet production in proton-proton collisions at √ s = 2.”
Heavy-quarkonium suppression in p-A collisions from parton energy loss in cold QCD matter (2012, methodology): “As can be seen from Table 4, saturation without energy loss still gives a fair description of PHENIX data, χ2/ndf = 2.7 (as well as EPS09 and DSSZ to a lesser extent), although saturation and nPDF effects alone would totally fail to reproduce E866 data.”
Study of J/ψ production and cold nuclear matter effects in pPb collisions at $ \sqrt{{{s_{NN }}}} $ = 5 TeV (2013, methodology): “[3], considering the parton shadowing with EPS09 parameterisation.”
Extraction of heavy-flavor transport coefficients in QCD matter (2018, methodology): “We report the expected effects using the EPS09NLO [25] and EPPS16 [29] parameterizations of the nuclear PDF modifications, which both depend on x, Q2 and the mass number A, and are defined as RAi (x,Q 2) = fAi (x,Q 2)/fpi (x,Q 2), where i denotes the parton type (gluon, valence quark or sea quark) a”