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Nuclear effects in neutrino-nucleus DIS

Nuclear effects in neutrino-nucleus DIS. Shunzo Kumano High Energy Accelerator Research Organization (KEK) Graduate University for Advanced Studies (GUAS) on behalf of Masanori Hirai Tokyo University of Science. in collaboration with Koichi Saito.

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Nuclear effects in neutrino-nucleus DIS

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  1. Nuclear effects in neutrino-nucleus DIS Shunzo Kumano High Energy Accelerator Research Organization (KEK) Graduate University for Advanced Studies (GUAS) on behalf of Masanori Hirai Tokyo University of Science in collaboration with Koichi Saito Our nuclear PDF page: http://research.kek.jp/people/kumanos/nuclp.html Sixth International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region May 18 - 22, 2009, Sitges, Barcelona, Spain http://nuint09.ifae.es/ May 21, 2009

  2. Contents Introduction • Motivations for nuclear structure functions in  reactions • Kinematics, Structure functions in  deep inelastic scattering (DIS) Nuclear modifications of PDFs • Parton Distribution Functions (PDFs) in the nucleon • Introduction to physics mechanisms for nuclear modifications • Recent global analyses of nuclear PDFs Kulagin, Petti; Eskola, Paukkunen, Salgado; Schienbein, Yu, Keppel, Morfin, Olness, Owens; Hirai, Kumano, Nagai; de Florian, Sassot • Recent JLab measurements 3. Summary

  3. Introduction

  4. Motivations for nuclear structure functions in  reactions Basic interest to understand hadron structure, Determination of fundamental constants Perturbative & non-perturbative QCD Understanding of nuclei in terms of quark and gluon degrees of freedom. ResonanceDIS: Transition from hadron degrees of freedom to quark-gluon d.o.f. Fundamental constants: s , sin2W (2)Practical purposes for nuclear PDFs Current  DIS (Fe, Pb targets) Nuclear corrections are important for extracting nucleonic PDFs. Neutrino oscillation Nuclear effects in n + 16O Other high-energy nuclear reactions Quark-hadron matters, Cosmic-rays air shower, …

  5. Kinematics of l+Nl’+X z

  6. valence-quark distributions Neutrino-Nucleon Scattering: charged current (CC) In parton model (leading order)

  7. Recent neutrino DIS experiments M. Tzanov et al. (NuTeV), PRD74 (2006) 012008. Future: MINERnA (He, C, Fe, Pb), …

  8. Nuclear Modifications of Parton Distribution Functions

  9. Recent activities  uncertainties  NNLO  QED  s – s  charm for LHC Recent papers on unpolarized PDFs It is likely that I miss some papers! CTEQ(uncertainties) D. Stump (J. Pumplin) et al., Phys. Rev. D65 (2001) 14012 & 14013. (CTEQ6) D. Pumplin et al., JHEP, 0207 (2002) 012; 0506 (2005) 080; 0602 (2006) 032; 0702 (2007) 053; PRD78 (2008) 013004. (charm) PR D75 (2007) 054029; (strange)PRL 93 (2004) 041802; Eur. Phys. J. C40 (2005) 145; JHEP 0704 (2007) 089. GRV(GRV98) M. Glück, E. Reya, and A. Vogt, Eur. Phys. J. C5 (1998) 461. (GJR08) M. Glück, P. Jimenez-Delgado, and E. Reya, Eur. Phys. J. C53 (2008) 355. MRST A. D. Martin, R. G. Roberts, W. J. Stirling, and R. S. Thorne, (MRST2001, 2002, 20033) Eur. Phys. J. C23 (2002) 73; Eur. Phys. J. C28 (2003) 455; (theoretical errors) Eur. Phys. J. C35 (2004) 325; (2004) PL B604 (2004) 61; (QED) Eur. Phys. J. C39 (2005) 155; PL B636 (2006) 259; (2006) PRD73 (2006) 054019; PL B652 (2007) 292. (2009)arXiv:0901.0002. Alekhin S. I. Alekhin, PRD68 (2003) 014002; D74 (2006) 054033. BB J. Blümlein and H. Böttcher, Nucl. Phys. B774 (2007) 182-207. NNPDF S. Forte et al., JHEP 0205 (2002) 062; 0503 (2005) 080; 0703 (2007) 039. H1 C. Adloff et al., Eur. Phys. J. C 21 (2001) 33; C30 (2003) 1. ZEUS S. Chekanov et al., PRD67 (2003) 012007; Eur. Phys. J. C42 (2005) 1. Recent upgrades

  10. Parton Distribution Functions (PDFs) in the nucleon http://durpdg.dur.ac.uk/hepdata/pdf.html A. D. Martin, W. J. Stirling, R. S. Thorne, G. Watt, arXiv: 0901.0002.

  11. Introduction toPhysics Mechanismsfor Nuclear Modifications

  12. 1.2 EMC NMC 1.1 E139 E665 1 0.9 0.8 0.7 0.001 0.01 0.1 1 Shadowing (qq fluctuation of photon) Nuclear modifications of structure function F2 Anti-shadowing Fermi motion of the nucleon For a review, see D. F. Geesaman, K. Saito, A. W. Thomas, Ann. Rev. Nucl. Part. Sci. 45 (1995)337. x Nuclear binding (+ Nucleon modification)

  13. Binding and Fermi motion

  14. 0.98 0.20 Because the peak shifts slightly (1 0.98), nuclear modification of F2 is created. Fermi motion binding

  15. Shadowing SK, Phys. Rept. 303 (1998) 183

  16. A typical multi-scattering model W. Melnitchouk and A. W. Thomas, PRD 47 (1993) 3783. Double scattering part Vector meson dominance Pomeron exchange Meson (Reggeon) exchange • Interference between Pomeron and Reggeon • Anti-shadowing ? (Brodsky and Lu, 1990)

  17. Determination of Nuclear Parton Distribution Functions

  18. Recent global analyses on nuclear PDFs • EPS09 • K. J. Eskola, H. Paukkunen, and C. A. Salgado, JHEP 04 (2009) 065. • Charged-lepton DIS, DY, p0 production in dAu. • SYKMOO08 • I. Schienbein, J. Y. Yu, C. Keppel, J. G. Morfin, F. I. Olness, and J. F. Owens, Phys. Rev. D 77 (2008) 044013. • Neutrino DIS (only NuTeV data). • HKN07 • M. Hirai, S. Kumano, and T. -H. Nagai, Phys. Rev. C 76 (2007) 065207. • Charged-lepton DIS, DY. • DS04 • D. de Florian and R. Sassot, Phys. Rev. D 69 (2004) 074028. • Charged-lepton DIS, DY. See also S. A. Kulagin and R. Petti, Phys. Rev. D 76 (2007) 094023; L. Frankfurt, V. Guzey, and M. Strikman, Phys. Rev. D 71 (2005) 054001.

  19. Kulagin and Petti’s analysis S. A. Kulagin and R. Petti, Phys. Rev. D76 (2007) 094023. • Although most global analyses assume rather a model-independent functional form with a number of parameters, their approach is different in the sense that only the “off-shell” effects in the nucleon are parametrized. • They tried to obtain structure functions rather than the PDFs. Nuclear structure functions = Conventional nuclear physics + Nucleon modifications in nuclear medium = Binding, Fermi motion + Pion excess + Shadowing (Multiple scattering) + Off-shell effects (with parameters to be determined from data) FMB: Fermi Motion + Binding OS: +Off-Sell PI: +Pion NS: +Nuclear Shadowing

  20. Global nuclear PDF analysis

  21. Data set for nuclear PDF analyses HKN07, PRC 76 (2007) 065207. • Charged-lepton DIS, DY 0.005 < x < 0.8, 1 < Q2 < 113 GeV2 • p0 production from d-Au collision • Neutrino DIS (NuTeV/CCFR): 0.015 < x < 0.75 Analysis results: total c2 / d.o.f. (# of parameter) • EPS09: 0.80 (17) • HKN07: 1.21 (12) • DS06: 0.80 (18) • SYKMOO08-A: 1.37 [n data]

  22. Functional form of initial distributions at Q02

  23. JLab • Factory MINARA HKN07 results and future experiments Fermilab J-PARC RHIC LHC eLIC eRHIC HKN07, PRC 76 (2007) 065207. Fermilab J-PARC GSI RHIC LHC eLIC eRHIC

  24. EPS09 HKN07 Valence Sea Gluon DS04 Comparison of nuclear PDFs Different analysis results are consistent with each other because they are roughly within uncertainty bands. Valence quark: Well determined except at small x. Antiquark: Determined at small x, Large uncertainties at medium and large x. Gluon: Large uncertainties in the whole-x region. EPS09 (K. J. Eskola et al.), JHEP 04 (2009) 065

  25. SYKMOO-08 (I. Schienbein et al.), PRD 77 (2008) 054013 Analysis of SYKMOO-08 (Schienbein et al.) Charged-lepton scattering Differences from typical NPDFs. Base-1 • remove CCFR data • incorporate deuteron corrections Base-2 corresponds to CTEQ6.1M with s≠sbar • include CCFR data Charged-lepton correction factors are applied. • s≠sbar Neutrino scattering Base-2: Using current nucleonic PDFs, they (and MRST) obtained very different corrections from charged-lepton data. Base-1: However, it depends on the analysis method for determining “nucleonic” PDFs.

  26. HKN07 MRSTW-08 analysis D. Martin, W. J. Stirling, R. S. Thorne, G. Watt, arXiv: 0901.0002. MRST98 nuclear correction DS04 DS04*NUCMOD(x) Deviations at large x: Same tendency as the Schienbein et al.’s.

  27. Recent measurements at JLab J. Seely et al., arXiv: 0904.4448 Results indicate that nuclear modifications may not be described by usual A (and density) dependence for light nuclei.

  28. Summary  Global analyses: Different results are roughly consistent with each other. Valence quark: Well determined except at small x. Antiquark: Determined at small x, Large uncertainties at medium and large x. Gluon: Large uncertainties in the whole-x region. Schienbein et al.’s analysis of neutrino-Fe data in 2008  Differences from SLAC measurements and parametrizations!?  Neutrino oscillation 1. Studies of resonance  DIS Transition from hadron degrees of freedom to quark-gluon. 2. Nuclear corrections in n + 16O  Future n experiments 1. MINERnA  Nuclear corrections in F3 2. Neutrino factory: Proton and deuteron targets instead of Fe and Pb.  “Correct” valence-quark distributions in “the nucleon”.

  29. The End The End

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