1 EPS08 - An improved global analysis of nuclear PDFs including RHIC data Kari J. Eskola Department of Physics, University of Jyväskylä Helsinki Institute.

Slides:



Advertisements
Similar presentations
1 Global reanalysis of nuclear PDFs Kari J. Eskola, Department of Physics, University of Jyväskylä Helsinki Institute of Physics hep-ph/ , in collaboration.
Advertisements

Lara De Nardo BNL October 8, 2007 QCD fits to the g 1 world data and uncertainties THE HERMES EXPERIENCE QCD fits to the g 1 world data and uncertainties.
Low x meeting, Sinai Alice Valkárová on behalf of H1 collaboration LOW x meeting 2005, Sinaia H1 measurements of the structure of diffraction.
Longitudinal Spin at RHIC 29 th Winter Workshop on Nuclear Dynamics February 7, 2013 Cameron McKinney.
Pawan Kumar NetrakantiPANIC-2005, Santa Fe1 Pion, proton and anti-proton transverse momentum spectra in p+p and d+Au collisions at  s NN = 200 GeV Outline:
Constraining the polarized gluon PDF in polarized pp collisions at RHIC Frank Ellinghaus University of Colorado (for the PHENIX and STAR Collaborations)
May 2005CTEQ Summer School1 Global Analysis of QCD and Parton Distribution Functions Dan Stump Department of Physics and Astronomy Michigan State University.
Particle Production in p + p Reactions at GeV K. Hagel Cyclotron Institute Texas A & M University for the BRAHMS Collaboration.
Lecture I: pQCD and spectra. 2 What is QCD? From: T. Schaefer, QM08 student talk.
Current: –Experiment: Extensive Drell-Yan p-p and p-d Expt. (E866) ; Charm production in Neutrino Scattering (CCFR, NuTeV) … etc. –Expected Advances in.
STAR Patricia Fachini QM20081 ρ 0 Production at High p T in Central Au+Au and p+p collisions at  s NN = 200 GeV in STAR STAR Patricia Fachini Brookhaven.
Looking for intrinsic charm at RHIC and LHC University of São Paulo University of Pelotas F.S. Navarra V.P. Gonçalves Winter Workshop on Nuclear Dynamics.
Cold Nuclear Matter E ff ects on J/ ψ as Constrained by d+Au Measurements at √s NN = 200 GeV in the PHENIX Experiment Matthew Wysocki University of Colorado.
1 Hadron multiplicities, p T -spectra and net-baryon number in central Pb+Pb collisions at the LHC Kari J. Eskola, Department of Physics, University of.
Sept 2003PHYSTAT11 … of short-distance processes using perturbative QCD (NLO) The challenge of Global Analysis is to construct a set of PDF’s with good.
Mar. 17, 2006 Imran Younus Probing Gluon Polarization with Longitudinally Polarized p+p Collisions at  s = 200 GeV.
Cold nuclear matter effects on dilepton and photon production Zhong-Bo Kang Los Alamos National Laboratory Thermal Radiation Workshop RBRC, Brookhaven.
Paul Laycock University of Liverpool BLOIS 2007 Diffractive PDFs.
1 Methods of Experimental Particle Physics Alexei Safonov Lecture #14.
AAC analysis of polarized parton distributions with uncertainties Shunzo Kumano, Saga University 12th.
QCD Analysis and Fragmentation Functions in the BELLE Experiment
Glauber shadowing at particle production in nucleus-nucleus collisions within the framework of pQCD. Alexey Svyatkovskiy scientific advisor: M.A.Braun.
Carl Gagliardi – QCD at High Energy/Small x 1 QCD at High Energy/Small x Experimental Overview Outline What do we know? Things to learn from the next RHIC.
Matt Durham - Hard Probes Heavy Quarks at Low-x J. Matthew Durham
As one evolves the gluon density, the density of gluons becomes large: Gluons are described by a stochastic ensemble of classical fields, and JKMMW argue.
Luca Stanco - PadovaQCD at HERA, LISHEP pQCD  JETS Luca Stanco – INFN Padova LISHEP 2006 Workshop Rio de Janeiro, April 3-7, 2006 on behalf of.
1 Nov. 15 QM2006 Shanghai J.H. Lee (BNL) Nuclear Induced Particle Suppression at Large-x F at RHIC J.H. Lee Physics Department Brookhaven National Laboratory.
Experimental Approach to Nuclear Quark Distributions (Rolf Ent – EIC /15/04) One of two tag-team presentations to show why an EIC is optimal to access.
Future  G Measurements at STAR Renee Fatemi University of Kentucky RHIC Spin Meeting, LBNL, November 21st 2009.
High p_T at LHC Tokaj, March 17, Expected nuclear modifications and pseudorapidity asymmetry at the LHC George Fai Kent State University Collaborators:
R CP Measurement with Hadron Decay Muons in Au+Au Collisions at √s NN =200 GeV WooJin Park Korea University For the PHENIX Collaboration.
QCD analysis of the nucleon spin structure function data in next to leading order in α S The polarized gluon distribution in the nucleon Jechiel Lichtenstadt.
Predictions for high energy neutrino cross-sections from ZEUS-S Global fit analysis S Chekanov et al, Phys Rev D67, (2002) The ZEUS PDFs are sets.
Cold Nuclear Matter effects at RHIC Latest results (run 2008) Frédéric Fleuret - LLR1/18.
INTRINSIC AND EXTRINSIC P T EFFECTS ON J/  SHADOWING This work, on behalf of E. G. Ferreiro F. Fleuret J.-P. Lansberg A. Rakotozafindrabe Work in progress…
The Role of Higher Twists in Determining Polarized Parton Densities E. Leader (London), A. Sidorov (Dubna), D. Stamenov (Sofia) 10th International Workshop.
Measurements of Nuclear Structure Functions at small Bjorken-x with EIC --An extension of Jlab 12 GeV proposal PR Lingyan Zhu Jlab proposal PRL10-012:
Energy Scan of Hadron (  0 ) Suppression and Flow in Au+Au Collisions at PHENIX Norbert Novitzky for PHENIX collaboration University of Jyväskylä, Finland.
7 th April 2003PHOTON 2003, Frascati1 Photon structure as revealed in ep collisions Alice Valkárová Institute of Particle and Nuclear Physics Charles University.
Nuclear matter effects in charmonium production in proton-nucleus collisions‏ Hermine K. Wöhri LIP – Lisbon, Portugal QWG 2008, Nara, Japan, December 2008.
Status of Recent Parton Distribution Analyses Hung-Liang Lai Department of Science Education Taipei Municipal Teachers College Introduction Time evolution.
HERMES による パートン helicity 分布関数の QCD 解析 Tokyo Inst. of Tech. 1. Quantum Chromo-Dynamics (QCD) 2. Parton Helicity Distribution and Nucleon Spin Problem 3.
SWADHIN TANEJA (STONY BROOK UNIVERSITY) K. BOYLE, A. DESHPANDE, C. GAL, DSSV COLLABORATION 2/4/2016 S. Taneja- DIS 2011 Workshop 1 Uncertainty determination.
1 Charged hadron production at large transverse momentum in d+Au and Au+Au collisions at  s=200 GeV Abstract. The suppression of hadron yields with high.
Isabell-A. Melzer-Pellmann DIS 2007 Charm production in diffractive DIS and PHP at ZEUS Charm production in diffractive DIS and PHP at ZEUS Isabell-Alissandra.
H1 QCD analysis of inclusive cross section data DIS 2004, Štrbské Pleso, Slovakia, April 2004 Benjamin Portheault LAL Orsay On behalf of the H1 Collaboration.
Global QCD Analysis of Polarized SIDIS Data and Fragmentation Functions Tokyo Tech 1. Motivation 2. pQCD Analysis of Fragment Functions (FFs) 3. Results.
Forward di-jet production in p+Pb collisions Centre de Physique Théorique Ecole Polytechnique & CNRS Cyrille Marquet A. van Hameren, P. Kotko, K. Kutak,
D Parton Distribution Functions, Part 2. D CT10-NNLO Parton Distribution Functions.
MSTW update James Stirling (with Alan Martin, Robert Thorne, Graeme Watt)
Azimuthal correlations of forward di-hadrons in d+Au collisions at RHIC Cyrille Marquet Theory Division - CERN Based on :C.M., Nucl. Phys. A796 (2007)
Kazutaka Sudoh (KEK) INPC2007, Tokyo June 5, 2007 Global Analysis of Hadron-production Data in e + e - Annihilation for Determining Fragmentation Functions.
Suppression of high P T hadron spectra in p+A collisions Wei-Tian Deng In Collaboration with: Rong Xu & Xin-Nian Wang arXiv:
(di)-Hadron Production in d+Au Collisions at RHIC Mickey Chiu.
Nuclear PDFs at NLO — status report & review of the EPS09 results Kari J. Eskola University of Jyväskylä & Helsinki Institute of Physics (substituting.
N. RaicevicMoriond QCD Structure Functions and Extraction of PDFs at HERA Nataša Raičeviċ University of Montenegro On behalf of the H1 and ZEUS Collaborations.
1 Proton Structure Functions and HERA QCD Fit HERA+Experiments F 2 Charged Current+xF 3 HERA QCD Fit for the H1 and ZEUS Collaborations Andrew Mehta (Liverpool.
1 A M Cooper-Sarkar University of Oxford ICHEP 2014, Valencia.
Inclusive jet photoproduction at HERA B.Andrieu (LPNHE, Paris) On behalf of the collaboration Outline: Introduction & motivation QCD calculations and Monte.
Measurements of ΔG Focus on COMPASS data ΔG from scaling violations
Hadron-structure studies at a neutrino factory
Determination of nuclear PDFs in the EIC era (Status of NPDFs and our requests to EIC experimentalists) Shunzo Kumano High Energy Accelerator Research.
Polarized PDF (based on DSSV) Global Analysis of World Data
Masanori HIRAI 2006, Nov 9, Tokyo-u
Kinematic Map in x,Q for CTEQ4
Nuclear Modifications of Parton Distribution Functions
Shadowing & quenching two stories in nuclear colliding
New d+Au RHIC data show evidence for parton saturation
A prediction of unintegrated parton distribution
Measurements of ΔG Focus on COMPASS data ΔG from scaling violations
Presentation transcript:

1 EPS08 - An improved global analysis of nuclear PDFs including RHIC data Kari J. Eskola Department of Physics, University of Jyväskylä Helsinki Institute of Physics KJE, Hannu Paukkunen, Carlos Salgado, arXiv: [hep-ph] 3rd Workshop on High-p T Physics at LHC Tokaj, 16 March, 2008

2 Collinear QCD factorization & PDFs Inclusive hard process cross sections in hadronic and nuclear collisions, e.g. A+B  k+l + anything (LO below) : Parton Distribution Functions number density distributions (in LO at least) universal = process-independent, specific to A and B contain nonpertubative input at an initial scale Q 0 2 obey DGLAP scale evolution equations of pQCD: Calculable in pQCD

3 Global analysis of PDFs = DGLAP-evolved PDFs + constraints from hard pQCD process data + constraints from sum rules (momentum, charge, baryon#) Procedure : iterate until best fit, best set of initial parameters {a i } found { f i (x,{a j }) } at Q 0, model independent DGLAP Comparison with data at various x & Q noVary {a j } { f i (x) } at Q>Q 0 Min(chi 2 ) ? Impose sum rules

4 Difficulties in extracting nonperturbative input for PDFs at fixed Q data not at one fixed Q 2 but correlated in x and Q 2 - kinematic ranges & data precision vary from one experiment to another - how to account for systematic uncertainties, for overall-normalization errors? - nPDF analysis more complicated than free proton PDFs: ▪ not enough data at small x & perturbative Q 2 ! ▪ A-dependence [under control], spatial dependence [open question],… perturbative nonperturbative f i/A (x,Q 2 ) = f i/p (x,Q 2 ) /

5 1.EKS98 (Eskola, Kolhinen, Ruuskanen, Salgado) [ hep-ph/ ,hep-ph/ ] - 1st global analysis for nPDFs - very good fits to nuclear DIS & DY data obtained with sum rules imposed – it works! 2. HKN, HKM (Hirai, Kumano, Nagai, Miyama) [LO hep-ph/ ,hep-ph/ ; HKN_NLO hep-ph] - automated chi 2 minimization - first uncertainty estimates for the nPDFs 3. nDS (de Florian, Sassot) [hep-ph/ ] - first NLO global analysis for nPDFs 4. EPS08 (Eskola, Paukkunen, Salgado) [ hep-ph] - first global analysis with RHIC data included Global analyses for… Free proton PDFs: CTEQ, MRST, GRV,… Nuclear PDFs:

6 EKS98: ▪ pioneering analysis Nucl. Phys. B535 (1998) 351, [hep-ph/ ] ▪ (x, Q 2,A)-dependent modifications; parametrization for general use: Eur. Phys. J. C9 (1999) 61 [hep-ph/ ] gluons sea quarks valence quarks Got the Q 2 -slopes right!

7 Last year in the High-pT LHC workshop in Jyväskylä: - reported uncertainty estimates for EKS98-type of global analysis, with automated chi2 minimization and DIS&DY data [EKPS, hep-ph/ ] - discussed the need to include RHIC data in the global analysis - Need stronger gluon shadowing at x<0.03 ? - Uncertainty estimates tied to the fit function forms valence sea F2(A)/F2(D) gluons

8 Now, for the EPS08 1. Include RHIC high-pT pion & negative-h data from d+Au - forward-rapidity data  constrained region extended down to x~ Improve the chi 2 minimization procedure - introduce weighting of different data sets  emphasize the constraints for gluons - account for given overall normalization errors of the data 3. Answer Q: Can the strong gluon shadowing suggested by BRAHMS forward data be accommodated together with the DIS&DY data in a global DGLAP analysis? = can a good global fit still be obtained? = can the nuclear effects be factorized into the nPDFs?

9 Define the PDFs of bound protons w.r.t. the known free proton PDFs: PDFs of the bound neutrons from isospin symmetry: u n/A =d p/A, d n/A =u p/A Similarly to EKS98, parametrize initial distributions at Q 0 =1.3 GeV in terms of three different initial modifications R i (x,Q 0 ): valence, sea & gluons piecewise construction: Sum rules imposed baryon # conservation  constrains mainly valence momentum conservation  constrains mainly gluons EPS08 framework = similar to EKS98

10 - A-dependence is in the parameters e.g. y a =y a (C) (A/12) p(ya) - new: more flexible small-x fit function, with no saturation of shadowing f A /f p ~ x -dA /x -dP  0 when x  0 (dA<dP) EPS08 framework

11 - [almost] no constraints for large-x sea&gluon modifications  fix gluons to valence R V in the EMC-effect region [support from (yet unpublished) PHENIX photon data in Au+Au] - Fast DGLAP solver now our own [HannuP] -- earlier we used CTEQ’s - Lots of manual labour to figure out which parameters are important [HannuP] !  Minimize chi 2 for 15 free fit parameters

12 The data used in EPS08 DIS: l+A (484 points) SLAC-E-139 NMC 95, 95re, 96 + EMC - leave E665 out Drell-Yan in p+A (92) E772 E866 + new input RHIC pi and h - in d+Au (51) BRAHMS, fwd PHENIX, mid-rap. STAR, mid-rap. Include only the region p T >2 GeV #datapoints = 627

13 Inclusive single hadron production at high pT: selection of RHIC data pQCD: p+pbar, pp: LO pQCD with K(s) works ~OK [KJE & H. Honkanen, hep-ph/ ] d+Au at RHIC: KKP We also exclude the region q T < 2 GeV from the global fit at pT< 2 GeV too steep slopes - also at NLO; FF uncertainties ? To avoid the Cronin effect complications with protons (assumed to be related to hadronization), we include in the EPS08 fit only pion data, and fwd-rap. h- data

14 New elements in EPS08 – improvements in chi 2 minimization 1.Weights w N for data sets N with these, we emphasize those data sets which provide important constraints but whose number of data points is small 2. Treatment of the additional overall normalization errors σ norm given by the experiment – similar procedure used also by CTEQ: - f N is determined by minimizing the chi 2 N for each data set N, i.e. for each parameter-set candidate during the overall chi 2 minimization - ”penalty factor” (…) 2 accounts for the fact that f N =1 should be the optimal value  the normalization given by the experiment usual definition now define

15 The results from EPS08

16 DIS & EPS08

17 EPS08 has the strongest gluon shadowing which still agrees with the F2 Q2-slopes ! Constraints for gluons from the first 3 panels of F2(Sn)/F2(C) in DIS > 0

18 DY & EPS08

19 EPS08 and RHIC pion data from d+Au: good agreement obtained when the given additional overall-normalization errors are accounted for: f N ≠ 1 ! PHENIX σ norm =10% STAR σ norm =17%

20 EPS08 and forward-rapidity negative hadron RHIC data: Good agreement obtained for p T >2 GeV From the EPS08 fit f N =1.02 not a big effect BRAHMS σ norm =5% here f N =0

21 The EPS08 nuclear effects at the initial scale Q=1.3 GeV Note the strong gluon shadowing! Constrained region Unconstrained region

22 Comparison with earlier global analyses Much more gluon shadowing in EPS08 -- correspondingly more antishadowing EPS08: chi 2 /N = 0.71 EKPS

23 Conclusions - RHIC data now in the global analysis of nPDFs, for the 1st time - the constrained x-region has been extended from x>0.01 to x> chi 2 analysis improved by introducing + weights for data sets + treatment of overall normalization errors - very good agreement obtained with DIS and DY data, and also with the p T >2 GeV RHIC pion data at midrapidity and with h- data at fwd rapidity  universal nPDFs and factorization seem OK - treatment of normalization errors led to a good simultaneous agreement w. PHENIX and STAR pion data - p T <2 GeV region in hadron production in d+Au at RHIC still difficult  need FF improvements, impact parameter dependent nPDFs,…

24 - thanks to the weights given to the RHIC data, the EPS08 results correspond to the strongest shadowing which is still in agreement with the Q2-slopes of F2 measured at DIS - gluon shadowing in EPS08 is much stronger than in earlier global analyses! - More data needed ! next: include RHIC photons from Au+Au hope to have D production in d+Au at RHIC hope for a p+Pb program at LHC, too - EPS08 now available at - Gluon shadowing still under debate…  use EPS08 parallel with EKS98