1. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 1 Charmonium Production in Media Martin zur Nedden Humboldt-Universität zu Berlin for the HERA-B Collaboration International Workshop on Heavy Quarkonia 2008 December 2 – 5 2008, Nara Women University, Japan Quarkonia in Media / Production

2. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 2 Charmonium Production in Media 920 GeV protons p + A  X,  s = 41.6 GeV The HERA-B Experiment data taking up to march 2003 Spectrometer at the HERA storage ring: proton-fixed target

3. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 3 Charmonium Production in Media Contents Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

4. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 4 Charmonium Production in Media Contents: Part 1 Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

5. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 5 Charmonium Production in Media Hadronic Production of Heavy Quarks production in hadronic interaction Parton-Density-Function within the hadron partonic cross setion hadronisation: formation of hadrons with heavy quarks or quarkonia stats factorisation of the process

6. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 6 Charmonium Production in Media Quarkonia Formation Hadronization: formation of Quarkonia (J/ψ, ψ’, χ c, Υ) long distance (~1/(m c v)) process: non-perturbative calculations and input from experiments needed, model dependence: CSM, COM, CEM, NRQCD qq formation: production of heavy quarks in media short distance (~1/m c ) / high momentum process: perturbative calculation PDF

7. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 7 Charmonium Production in Media based on Glauber-model:  ≠ 1  „dependence” Nuclear Effects for Charmonium Production p μ/e+μ/e+ μ/e-μ/e- J/  final state formation effects: nuclear absorption comover absorption multiple scattering + energy loss initial state effects: shadowing (nuclear PDFs) parton energy loss intrinsic charm HERA-B: acsess to production in media measurement of  using C and W wires:

8. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 8 Charmonium Production in Media x F -Dependence of Nuclear Effects for c  = 0.5 fm xFxF [fm] 0.230 010 -0.24 p μ/e+μ/e+ μ/e-μ/e- J/  formation time and length: (x F ) =   c   =  (x F ) boost of J/  w.r.t. nucleus

9. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 9 Charmonium Production in Media Contents: Part 2 Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

10. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 10 Charmonium Production in Media HERA-B Detector and Trigger p- beam z [cm] C Ti W Muon-Trigger Electron-Trigger

11. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 11 Charmonium Production in Media 150 M di-lepton trigger events (e + e - / μ + μ - triggers)  ~ 300 000 J/ψ  ~ 15 000  c  ~ 5 000 ψ’ 210 M minimum bias events HERA-B Data Samples m(e + e - ) [GeV/c 2 ] entries/(30 MeV/c 2 ) 10 3 10 4 2.5 3.0 3.5 4.0 ~ 120 000 J/ψ ~ 2 200 ψ′ σ J/ψ ~ 64 MeV ~ 120 000 J/ψ ~ 2 200 ψ′ σ J/ψ ~ 64 MeV e+e-e+e- J/ψ ψ′ψ′ entries/(25 MeV/c 2 ) m(μ + μ - ) [GeV/c 2 ] 10 3 10 4 2.8 3.2 3.6 4.0 μ+μ-μ+μ- J/ψ ψ′ψ′ ~ 170 000 J/ψ ~ 3 000 ψ′ σ J/ψ ~ 44 MeV ~ 170 000 J/ψ ~ 3 000 ψ′ σ J/ψ ~ 44 MeV Three target materials: pC,pW and pTi collisions absolute cross section measurements for di-lepton triggered data need independent reference cross section measured with minBias events: σ(J/ψ) = (502 ± 44) nb/nucl.

12. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 12 Charmonium Production in Media Contents: Part 3 Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

13. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 13 Charmonium Production in Media J/  p T Distributions HERA-B combined result Increase of with A (radius of nucleus): linear dependence on the nuclear path length of the incident parton NA50 E672/706/771/789 HERA-B

14. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 14 Charmonium Production in Media J/ψ x F - Distribution w xF : width Δx F : shift width increasing with Radius of nucleus shift increasing with Radius of nucleus p T distribution: increase of with radius x F distribution: increasing width and shift with radius both effects compatible with initial state energy loss HERA-B combined result

15. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 15 Charmonium Production in Media Contents: Part 4 Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

16. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 16 Charmonium Production in Media Measurement of Nuclear Dependence nuclear dependence parameter α extracted from the ratio of carbon and tungsten J/ψ production cross sections Final result form HERA-B: result based on double wire runs only Measurement of the x F and p T dependence of α based on full data sample: Using the measured kinematical distributions of carbon and tungsten (normalized) (full data sample of single and double wire runs)

17. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 17 Charmonium Production in Media Nuclear Dependence Measurement: p T Good agreement of E866 an HERA-B measurement in the common region of p T p T broadening effect as seen by E866 confirmed

18. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 18 Charmonium Production in Media Theoretical Models for x F Dependence Separate description and integration: final state absorption interaction with co-movers energy loss (EL) shadowing of nuclear PDFs intrinsic charm quark components (IC) Nuclear Parton Density Functions: Eskola, Kolhinen, Salgado (EKS, Eur.Phys.JC9(1999)61) scale dependence of a proton within a nucleon via DGLAP initial PDF from CTEQ4L and LO-GRV Eskola, Paukkunen, Salgado (EPS, arXiv:0802.0139) improved leading order DGLAP including NLO Hirai, Kumano, Nagai (HKN, Phys.Rev.C70(2004)044905) nuclear structure functions and Drell-Yan cross sections weak anti-shadowing at negative x F Initial state energy loss: Gavin, Milana (GM, Phys.Rev.Lett.68(1992)1834) based on multiple scattering approach elastic scatterings of quarks and gluons Brodsky, Hoyer (BH, Phys.Lett.B298(1993)165) modification of GM Model calculation by R. Vogt: - Phys.Rev.C61(2000)035203 - Phys.Rev.C71(2005)054902 - Private communication

19. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 19 Charmonium Production in Media Theoretical Descriptions: Overview All calculations done by Ramona Vogt in 2007/2008

20. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 20 Charmonium Production in Media Nuclear Dependence Measurement: x F average α measurement form HERA-B: Final result form HERA-B, to be published in Eur.Phys.J

21. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 21 Charmonium Production in Media Reggeon Phenomenology Model Boreskov and Kaidalov (JEPT Lett.D77(2003)599): predicts anti-screening effects in negative x F region - color less state containing quarks (i.e. D-Mesons) propagates trough the nucleus - large size (consisting of D-mesons), large interaction cross section: energy loss - J/ψ projected out of energy dependent color-less state HERA-B E866 HERA-B result within uncertainties qualitatively compatible

22. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 22 Charmonium Production in Media Contents: Part 5 Introduction HERA-B Detector J/ψ: Kinematical Distributions J/ψ: Nuclear Dependence χ c Production

23. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 23 Charmonium Production in Media χ c Production Relative measurement of χ c to J/ψ production HERA-B: Selection by γ Selection (E γ ) and invariant mass measurement: making use of J/ψ production cross section from min.Bias data disentangle χ c1 and χ c2 by double Gaussian fits: separate cross section measurements background subtraction by mixed events separate analysis for electrons and muons full statistics in both channels: 15000

24. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 24 Charmonium Production in Media χ c Event Counting electrons muons Separation of χ c1 and χ c2 in the ΔM spectra: double Gaussian fit with some fixed parameters predicted by MC free parameters are the ratio and sum of event numbers

25. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 25 Charmonium Production in Media A-Dependence averaged result of HERA-B: Δα = 0.05 ± 0.04 Atomic mass number dependence: same principle as for J/ψ no significant difference in A-dependence within the statistical limits

26. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 26 Charmonium Production in Media Production Cross Section Ratio R(  c ) CDF (p-p) ISR (p-p) E771 (p-Si) E705 (p-Li) E369/ 610/ 673 (p- Be) 2002/3 final π-A Final result: R χc = (18.8 ± 2.8)% of the produced J/ψ’s come from χ c decays HERA-B HERA-B 2000 available statistics:

27. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 27 Charmonium Production in Media Final Results of χ c Final result form HERA-B, accepted for Phys.Rev.D (arXiv:0807.2167)

28. Martin zur Nedden, HU Berlin QWG Meeting, Nara 2008, p. 28 Charmonium Production in Media Summary HERA-B collected 300000 J/ , 15000 χ c and 220 Mio minimum bias events on nuclear targets (mainly carbon and tungsten) Final Results on charmonium production: J/  : inclusive production cross section J/  : x F and p T distributions in a new negative x F range J/  : nuclear dependence: tendency of enhancement in at x F <0  c : production ratio, disentanglement of χ c1 and χ c2 Final results on kinematics of J/  production, nuclear dependence of J/ψ and  c production are final and published (during 2008)