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Contalbrigo Marco

Contalbrigo Marco CLAS12 European Workshop 26 February 2009. Physics requiring RICH. Contalbrigo Marco. INFN Ferrara. CLAS12 European Workshop February 26, 2009.

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Contalbrigo Marco

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  1. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Physics requiring RICH Contalbrigo Marco INFN Ferrara CLAS12 European Workshop February 26, 2009

  2. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Kaon in SIDIS Approved by PAC34: PR12-09-07: Studies of partonic distributions using semi-inclusive production of Kaons PR12-09-08: Studies of Boer-Mulders Asymmetry in Kaon Electroproduction with Hydrogen and Deuterium Targets PR12-09-09: Studies of Spin-Orbit Correlations in Kaon Electroproduction in DIS with polarized hydrogen and deuterium targets

  3. DG small at 0.02<x<0.3 From DIS and pp scattering DS=0.33±0.03 Latest news from Deep Inelastic Scattering (DIS) e-print 0804.0422 Phys Lett B647 (2007) 8-17 Phys. Rev. D 75 (2007) 012007 Contalbrigo Marco CLAS12 European Workshop 26 February 2009 The Spin Structure of the Nucleon Describe the complex nucleon structure in terms of partonic degrees of freedom of QCD Important testing ground for QCD Proton’s spin Jg Jq Understanding of the orbital motion of quarks crucial!!!

  4. constrain the unpolarized strange sea disentangle distribution and fragmentation functions Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Correlation Functions Distribution Functions (DF) Fragmentation Functions (FF) Dqh(z) q(x) Hadron ID provides flavor tagging !!

  5. K K K PR12-09-07: H2 & D2 (54 days) X • Constrain strange sea • Reduce uncertainty on NS • (and S) fragmentation functions Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Strange parton distribution Isoscalar target Charge conjugation in FF

  6. Dqh flavor decomposition of quark helicity Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Correlation Functions Distribution Functions (DF) Fragmentation Functions (FF) D Hadron ID provides flavor tagging !!

  7. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Helicity distribution • Flavour decomposition of quark helicity • Is the light sea symmetrically polarized ?

  8. Hep-ex 0804.0422 PR12-09-07: NH3 (30 days) & ND3 (50 days) • Flavor decomposition of quark helicity Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Helicity distribution Flavor decomposition • Constrain very well the valence • Explore the valence-sea transient • Check sea polarization symmetry • Improve phenomenological fits indirect information on DG Isoscalar method

  9. M.Anselmino et al hep-ph/0608048 m02=0.25GeV2mD2=0.2GeV2 Constituent quark model (Pasquini et al). Contalbrigo Marco CLAS12 European Workshop 26 February 2009 ALL PT-dependence in SIDIS LL ALL 0.4<z<0.7 p+ ALL suggests broader kT distributions for f1 compared to g1 p- ALL may require non-Gaussian kT-dependence for different helicities and/or flavors

  10. M.Anselmino et al hep-ph/0608048 m02=0.25GeV2mD2=0.2GeV2 Contalbrigo Marco CLAS12 European Workshop 26 February 2009 ALL PT-dependence in SIDIS proton deuteron GRSV-2000+Kretzer PR12-09-09: NH3 (30 days) & ND3 (50 days) • Azimuthal asymmetry sensitive to the difference of kT -widths in PDFs • Complete set required for the flavor decomposition (H,D target +K,p ID)

  11. TMDs Correlation Functions pp pX pp pX AN √s = 20 GeV pT<2 GeV/c SIVERS Quark orbital angular momentum GPD E GPD ET green quark xF anti-green remnant Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Distribution Functions (DF) Off-diagonal elements: interference of partial-wave function for different orbital momentum states ┴ ┴ ┴ ┴ ┴

  12. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Sivers Function Distribution Functions (DF) Fragmentation Functions (FF)

  13. p+(u,d) K+(u,s) Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Sivers function M.Anselmino et al hep-ph/0805.2677 D. de Florian et al., Phys. Rev. D75 (2007) 114010 Clear example of flavor sensitivity thanks to hadron ID From kaon vs pion comparison Unpolarized SIDIS provides detailed description of FFs Polarized SIDIS provides information on sea contribution to Sivers: • saturation of sbar • clear negative tendency for dbar

  14. CLAS12 with transverse target Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Sivers function Still preliminary data Role of evolution ?

  15. eeppX hpmmX BOER-MULDERS Spin Orbit effect E615 NA10 g1L E866 h1 COLLINS Quark spin probe Contalbrigo Marco CLAS12 European Workshop 26 February 2009 TMDs Correlation Functions Distribution Functions (DF) ┴ ┴ ┴ ┴ ┴ Fragmentation Functions (FF)

  16. epe’hX • longitudinal to transverse photon flux Intrinsic kT “Cahn effect” (1978) Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Non-collinear SIDIS off unpolarized targets g1L h1

  17. EMC (1987) EMC (1987) Contalbrigo Marco CLAS12 European Workshop 26 February 2009 (Up to 2008) Cosnfmoments cosf cos2f E665 (1993) ZEUS (2000) • No hadron identification • No charge separation • Poor statistics forcos2f Qualitative agreement with expectations based on Cahn model, but investigation far to be conclusive

  18. epe’hX g1L • longitudinal to transverse photon flux h1 Leading twist Contalbrigo Marco CLAS12 European Workshop 26 February 2009 SIDIS off unpolarized targets

  19. Boer-Mulders function: extracted only from Drell-Yan same sign for u and d in agreement with most of the models sign change between DY and SIDIS • universality of TMDs PhysRevD77 (2008) 034035 Fit to Drell-Yan DATA x Contalbrigo Marco CLAS12 European Workshop 26 February 2009 FUU structure func. Expansion up to twist 3 pQCD CORRECTIONs Convolution integral over transverse momenta with implicit sum over quark flavours BOER-MULDERS x COLLINS Access to partonic transverse spin and momentum correlations in distribution and fragmentation CAHN EFFECT Sensitive to partonic intrinsic transverse momentum Fundamental prediction of QCD !

  20. extracted from e+e- collider data (BELLE) at much higher scale than SIDIS to be investigate at SIDIS scale too • evolution of TMDs only for pions still unknown for kaons • strange vacuum • strangeness in the nucleon Transversity 2008, Ferrara Dfav -Dunf FIT TO BELLE DATA Contalbrigo Marco CLAS12 European Workshop 26 February 2009 FUU structure func. Expansion up to twist 3 BOER-MULDERS x COLLINS Convolution integral over transverse momenta with implicit sum over quark flavours Access to partonic transverse spin and momentum correlations in distribution and fragmentation CAHN EFFECT Sensitive to partonic intrinsic transverse momentum Collins function:

  21. p- p- p- All contributions Boer-Mulders p+ p+ p+ Cahn (twist 4) V. Barone et al. Phys.Rev.D78:045022,2008 Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Cos2fmoments Non-zero ! Sign change with hadron charge ! ? Experiments still working hard to control systematics How large is the contribution at higher twist ? How to compare different Q2 ?

  22. epe’hX g1L • longitudinal to transverse photon flux h1 Twist-3 Leading twist Contalbrigo Marco CLAS12 European Workshop 26 February 2009 SIDIS off unpolarized targets

  23. BOER-MULDERS + COLLINS Access to Partonic transverse spin and momentum correlations In distribution and fragmentation CAHN EFFECT Access to Partonic intrinsic transverse momentum Contalbrigo Marco CLAS12 European Workshop 26 February 2009 FUU structure func. Expansion up to twist 3

  24. preliminary Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Cosf moments Large negative effect confirmed ! How large is the uncertainty in predictions from intrinsic transverse momentum distribution ? Is Cahn effect diluted by other terms ? Is the difference between p+ and p- the sign of a non-zero boer-mulders ?

  25. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Boer-Mulders kaon asymmetry @ CLAS12 Line: Phys Rev D78 045022 Boer-Mulders from Sivers Collins from e+e- data Band: Phys Rev D78 034035 Boer-Mulders from DY data Collins from chiral limit Excellent precision vs model uncertainties PR12-09-08: 54 days at L=1x1035 cm-2s-1

  26. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Collins function & transversity Distribution Functions (DF) Fragmentation Functions (FF)

  27. No kaon analysis Valence poorly constrained M.Anselmino et al hep-ph/0812.4366 CLAS12 with transverse target Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Collins function & transversity

  28. Limited knowledge on transverse momentum dependences Flavor decomposition often missing Evolution properties to be defined Role of the higher twist to be quantified UniversalityFundamental test of QCD Still incomplete phenomenology is asking for new inputs Crucial: completeness flavor tagging and five-fold differential extraction in all variables (x,z,Q2,PT) to have all dependencies resolved Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Executive summary TMDs are a new class of phenomena providing novel insights into the rich nuclear structure Non-zero results from DIS experiments provide promises but also open questions

  29. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 CLAS12: experimental set-up broad kinematical range multi-purpose detector for fixed target electron scattering experiments large luminosity Polarized beam H and D targets Pion and kaon, …. SSA • Large kinematic ranges accessible with CLAS12 are important for separation of • Valence region • Higher Twist contributions (Q2) • Perturbative regime (PT ≥ 1) Q2>1GeV2 W2>4 GeV2 y<0.85 MX>2GeV

  30. K central detector forward detector Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Kinematic dependence of K/ ratios Critical for separation moment range 2<PK<5 and q<25 degree PEPSI LEPTO predictions Only reliable ispidentification

  31. 0.4 0.0 - 0.6 ep+X generated reconstructed 0 0.5 1 1.5 PT Contalbrigo Marco CLAS12 European Workshop 26 February 2009 CLAS12 Acceptance MC studies CLAS12 SIDIS MC (LUND-PEPSI) used to study azimuthal moments from acceptance and radiative corrections for different pions.

  32. ep+X generated reconstructed PT PT Contalbrigo Marco CLAS12 European Workshop 26 February 2009 CLAS12 Acceptance MC studies CLAS12 SIDIS MC (LUND-PEPSI) used to study azimuthal moments from acceptance and radiative corrections for different pions. After acceptance correction the generated azimuthal moments are recovered with an error < 10% (dominant contribution to systematics) Even better results expected with a fully-differential analysis

  33. LTCC Contalbrigo Marco CLAS12 European Workshop 26 February 2009 A Rich detector for CLAS12 Only reliable ispidentification

  34. RICH 2/3 cm 60/80 cm Proximity Gap Replacement of LTCC with proximity focusing CsI Rich detector  good separation of p/K/p in the 2-5 GeV/c momentum range no impact on the baseline design of CLAS 12  minimum impact on spectrometer performace pad cathode coated with CsI film Contalbrigo Marco CLAS12 European Workshop 26 February 2009 A Rich detector for CLAS12 A Rich detector would strongly enhance the CLAS12 capabilities in particle identification and would open possibilities for new physics

  35. 4s K-pseparation at 5 GeV/c 80 % kaon eff. with 1:1000 p rejection 95 % kaon eff. with 1:100 p rejection Already with 2 sectors gain of factor ~3 in the relevant z region of interest without RICH with RICH Contalbrigo Marco CLAS12 European Workshop 26 February 2009 A Rich detector for CLAS12 MC simulation:  3 cm thick C5F12 radiator 80 cm CH4 proximity gap  1 cm pixel pad size  5 o-30 o radiator polar angle

  36. 2-D Collins moments forp± x vs z z vs Ph Contalbrigo Marco CLAS12 European Workshop 26 February 2009 ┴

  37. I[h1H1┴] Transversity & Collins Contalbrigo Marco CLAS12 European Workshop 26 February 2009 d 1-Hadron Production (ep epX) le ST le SL le

  38. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Other leading twist DF

  39. Target SSA measurements at CLAS • Complete azimuthal coverage crucial for separation of sinf, sin2f moments ep→e’pX CLAS PRELIMINARY p1sinf+p2sin2f W2>4 GeV2 Q2>1.1 GeV2 y<0.85 0.4<z<0.7 MX>1.4 GeV p1= 0.059±0.010 p2=-0.041±0.010 p1=-0.042±0.015 p2=-0.052±0.016 p1=0.082±0.018 p2=0.012±0.019 PT<1 GeV 0.12<x<0.48 No indication of Collins effect for p0 (x20 more data in 2009)

  40. Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Collins frag.: Longitudinally polarized target Kotzinian-Mulders Asymmetry proton deuteron Pasquini et al. • Study the Collins function of kaons • Provides independent information on the RSMT TMD

  41. ep→e’pX p multiplicities in SIDIS M.Aghasyan Hall-C DSS (Q2=2.5GeV2) DSS (Q2=25GeV2) p+/- multiplicities at large z diverge from SIDIS predictions p0 multiplicities less affected by higher twists 0.4<z<0.7 kinematical range, where higher twists are expected to be small

  42. Wpu(k,rT) “Mother” Wigner distributions d2kT d2rT GPDs/IPDs TMD PDFs f1u(x,kT), .. h1u(x,kT) d2kT Contalbrigo Marco CLAS12 European Workshop 26 February 2009 Structure of the Nucleon quark polarization PDFs f1u(x), .. h1u(x) • Gauge invariant definition (Belitsky,Ji,Yuan 2003) • Universality of kT-dependent PDFs (Collins,Metz 2003) • Factorization for small kT. (Ji,Ma,Yuan 2005) Analysis of SIDIS and DVMP are complementary!

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