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Hadron structure study in forthcoming Drell-Yan experiments

Hadron structure study in forthcoming Drell-Yan experiments. Oleg Denisov CERN/INFN sez. di Torino 22.07.2009. Outline. Drell-Yan kinematics Unpolarised Drell-Yan Single (Transverse) polarised Drell-Yan Double polarised Drell-Yan J/Psi production and J/Psi <-> DY duality

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Hadron structure study in forthcoming Drell-Yan experiments

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  1. Hadron structure study in forthcoming Drell-Yan experiments Oleg Denisov CERN/INFN sez. di Torino 22.07.2009 Oleg Denisov

  2. Outline • Drell-Yan kinematics • Unpolarised Drell-Yan • Single (Transverse) polarised Drell-Yan • Double polarised Drell-Yan • J/Psi production and J/Psi <-> DY duality • Access to GPDs? • Some indications to the future Drell-Yan experiments • Future Drell-Yan experiments: • Fixed target experiments (COMPASS, E906, J-Park) • Collider experiments (RHIC, NICA SPD (Dubna), PAX (GSI) • Some conclusions Oleg Denisov

  3. Drell-Yan Kinematics (collinear case) S.Melis -> COMPASS Oleg Denisov

  4. Drell-Yan Kinematics (transverse motion) Oleg Denisov

  5. Unpolirised Drell-Yan angular distributions Oleg Denisov

  6. Unpolarised Drell-Yan angular distributions:Lam-Tung sum rule violation Oleg Denisov

  7. Unpolarised Drell-Yan angular distributions:Boer-Mulders function (cos(2ϕ) modulations) Oleg Denisov

  8. Drell-Yan cross section Oleg Denisov

  9. Single polarised Drell-Yan: cross section Oleg Denisov

  10. Single polarised Drell-Yan: cross section Oleg Denisov

  11. Sivers effect SIDIS <->DY A. Schafer – Mainz’09 J.C. Collins, Phys. Lett. B536 (2002) 43 Special thanks to A.V.Efremov J. Collins, talk at LIGHT CONE 2008

  12. Double polarised Drell-Yan: direct access to Transversity M.Nekipelov -> PAX Feasibility study is underway, polarised antiprotons(>20%) - not at all trivial issue Oleg Denisov

  13. J/Y – Drell-Yan duality I • J/Y – DY duality  close analogy between Drell-Yan and J/Y production mechanism: • Occurs when the gluon-gluon fusion mechanism of the J/Y production is dominated by the quark-quark fusion mechanism • We can expect that the duality is valid in the COMPASS cinematic range • Key issue for the applicability of the J/Y signal for the study of hadron spin structure • J/Y production mechanism by itself is an important issue   J/ substitution Oleg Denisov

  14. Experiment: Only 2 points. Therefore test DY and J/Y duality is of crucial importance in polarized case! Transversity and Boer-Mulders PDFs from J/Y production with low s (duality model) N. Anselmino, V. Barone, A. Drago, N. Nikolaev, Phys. Lett. B594 (2004) 1997 V. Barone, Z. Lu, B. Ma, Eur. Phys. J. C49 (2007) 967 A. Sissakian, O. Shevchenko, O. Ivanov, JETP Lett 86 (2007) 751 Ratios of cross­sections calculated with two models in comparison with the experimental data. Solid line corresponds to the ``duality'' model. Dashed line corresponds to the ``gluon evaporation'' model Dot­dashed line corresponds to ``gluon evaporation'' model without gluon contribution. Tests on the models for unpolarized J/Y production (gluon evaporation, NRQCD, ...) - COMPASS - NICA

  15. Drell-Yan processes and access to GPDs Very preliminary – feasibility is under discussion now, some indications: • O.Teryaev: Drell-Yan pair production in the pion-nucleon collisions for large xF (the region whose exploration is favourable in COMPASS kinematics) is sensitive to such an important and hot ingredient of pion structure as its light-cone distribution (DA). In other words in this kinematic range pion participate in the interaction coherently (as pion) rather then by only one of its quark. • References: • A.P.Bakulev, S.V.Mikhailov and N.G.Stefanis, Phys.Lett.B 508, 279 (2001) • A.Brandenburg, S.J.Brodsky, V.V.Khoze and D.Mueller, Phys.Rev.Lett. 73, 939 (1994) • A.Brandenburg, D.Mueller and O.V.Teryaev, Phys.Rev.D 53, 6180 (1996) • B.Pire, O.Teryaev: Semiexclusive DY – crucial test of the GPDs universality (time-like process contrary to the Deep Inelastic scattering) • Reference: • B.Pire, L. Szymanowski, arXiv:0905.1258v1 [hep-ph] 8 May 2009 Oleg Denisov

  16. GPD’s universality test ? Oleg Denisov

  17. Semiexclusive Drell-Yan? In the COMPASS case the (semi)exclusivity is provided by a simple cut on missing mass Oleg Denisov

  18. Some indications forthe future Drell-Yan experiments TMD PDFs – ALL are sizable in the valence quark region Sivers effect in Drell-Yan processes.
M. Anselmino, M. Boglione U. D'Alesio, S. Melis, F. Murgia, A. Prokudin 
Published in Phys.Rev.D79:054010, 2009 Oleg Denisov

  19. Some indications for the future Drell-Yan experiments Safe region: 4. < M < 9. Gev/c2 Oleg Denisov

  20. Some indications for the future Drell-Yan experiments • Drell-Yan experiments: • High luminosity (DY Cross Section is a fractions of nanobarns) and large angular acceptance, better pion or antiproton beams (valence anti-quark) • Sufficiently high energy to access ‘safe’ of background free Mll range ( 4 GeV/c < Mll < 9 GeV/c) • Good acceptance in the valence quark range xB > 0.05 and kinematic range: τ = xAxB = M2/s > 0.1 • Polarised Drell-Yan: • Good factor of merit (Fm), which can be represented as a product of the luminosity and beam (target) polarisation (dilution factor) (Fm~ L × Pbeam (f)) Oleg Denisov

  21. Future Drell-Yan experiment • Fixed target experiments (COMPASS, E906, J-Park) characterised by: • Very high luminosity (>1033 cm-2s-1) • Only muon in the final state (hadron absorber has to be used because of the ‘all forward’ geometry and high luminosity) • Light unpolarised targets (liquid hydrogen and deuterium) and solid state polirised targets (NH3, 6LD) • Pion, proton and (probably) antiproton (COMPASS) beams • Collider experiments (RHIC, NICA SPD, PAX) • Moderate luminosity • High universality (not only TMD PDFs, J/Psi and related aspect but also formfactors, various hard processes – not a topic of this talk) Oleg Denisov

  22. COMPASS experiment at CERN Oleg Denisov

  23. Why Drell-Yan @ COMPASS Large angular acceptance spectrometer SPS M2 secondary beams with the intensity up to 6x107 particles per second Large acceptance COMPASS Superconducting Toroidal Magnet Transversely polarized solid state proton target with a large relaxation time and high polarization, when going to spin frozen mode; a detection system designed to stand relatively high particle fluxes; a Data Acquisition System (DAQ) that can handle large amounts of data at large trigger rates; The dedicated muon trigger system • For the moment we consider two step DY program: • The program with high intensity pion beam • The program with Radio Frequency separated antiproton beam Oleg Denisov

  24. DY cross section and acceptance @ COMPASS C.Quintans -> COMPASS Oleg Denisov

  25. DY acceptance @ COMPASS Pure u-dominance region Prediction for Sivers function as a function of x, COMPASS acceptance in xp and acceptance coverage xπ.vs.xp Oleg Denisov

  26. Access to the TMD PDFs @ COMPASS Oleg Denisov

  27. Feasibility test @ COMPASS Oleg Denisov

  28. Pt range covered by COMPASS COMPASS Pt coverage Previous experiments: Oleg Denisov

  29. Sivers and expected statistical error @ COMPASS Oleg Denisov

  30. COMPASS: Summary • Pion and, later, antiproton beams (50-200 GeV), Drell-Yan process dominated by the contribution from the valence quarks (both beam and target), τ = x1x2 = Q2/s ≅ 0.05÷0.3 • Solid state polarised targets, NH3 and 6LD, in case of hydrogen target – pure u-dominance • Statistical error on single spin asymmetries is on the level 1÷2% • LoI already submitted to CERN SPSC, ‘go ahead’ for full proposal is obtained • Start date ≥ 2012 Oleg Denisov

  31. Other fixed target experiments: E906 and J-Park Luminosity ~ 1033 cm-2s-1 Beam energy – 120 GeV Start dates > 2010 Unpolirised Proton beam only Oleg Denisov

  32. NICA Facility at JINR Dubna • NICA could provide • unique possibilities for the spin program: • High energy proton • and deuteron beams • 2. High luminosity ( > 10 30 см-2с-1for proton beam) • 3. High polarization(>50% ) • 4. Spin rotation L/T • 5. High precision ofpolarization measurements • 6. 4 geometry detector • 7. Possibility to change beams energy with ~1 GeV step SPD Sourceof Polarized Ions(CIPIOSbased) for Nuclotron-M /NICAcomplex will provide  1010d (p) /pulse A.Nagaytsev -> NICA SPD 32

  33. Polarized proton beams parameters @ NICA 33

  34. NICA Spin Physics Detector (SPD) SPD Group at JINR is working on the preparation of the spin physics program (LoI) for NICA to operate with polarized beams of light nucleus. Studies of DY processes Studies of J/Y production processes Studies of elastic reactions Polarimetry Spin effects in one and two hadron production processes Spin effects in photoproduction Spin effects in various exclusive reactions Spectroscopy of quarkonia with any available decay modes Diffractive processes Hidden color in light nuclei Color transparency and others (studies of unpolarized pp reactions: direct photons, z-scaling etc)

  35. NICA SPD - feasibility Preliminary estimations of the Drell-Yan processes feasibility DY cross sections (nb) in comparison with PAX (GSI,FAIR) and possibility to increase the statistics (month of data taking)

  36. ACCESS to TMD PDFs – statistical errors estimare (very preliminary) The set of original software packages (MC simulation, generator etc.) were developed for the feasibility studies of DY polarized processes (to be published) The SSA asymmetries. Top:access to transversity and Boer-Mulders PDFs. (Sissakian, Shevchenko, Nagaytsev,PRD 72 (2005), EPJ C46 (2006)) Bottom: access to Sivers PDFs (Efremov,… PLB 612(2005), PRD 73(2006)); All SSA are estimated for 100 K DY events

  37. Side view of the NICA SPD experimental set-up: for µ+µ- pairs • - Toroid magnet system • Silicon or MicroMega (Vertex) • Drift chambers (DC) • - EM Calorimeter (EMC) • Range System (RS) • JINR contribution on RS for PANDA (G.Alexeev et al. Private commun.) • Trigger counters • EndCap detectors with RS, • tracking system and HCal/EMC Range System End Cap EM Calorimeter Sizes: Inner barrel length: 160 cm EMC ( ~ 50 cm): inner radius: 52 cm DC1 + Hod1: 102 cm RS: 10 layers(3 cmFe + 2 cm MDC) inner rad: 120 cm outerrad:170 cm Toroid Magnet DC and Trigger Vertex System

  38. NICA SPD muon Range System 3 GeV muon 10 GeV pion shower RS is accepted as main detector of Muon System for PANDA (G.Alexeev et al. Private commun.) RS can be used as: 1. Muon Filter 2. PID for protons and pions 3. To reduce background from muons produced by pion decays 4. Hadron Calorimeter with energy resolution ~ 100/sqrt(E) Minor: - Multiple Scattering - Problem with PID for particles with momenta less than 1 GeV Hardware tests RS+EMC at Nuclotron-M(JINR) or SPS(CERN) Eπ=0.5 GeV Muon energy, angle and correlation distributions

  39. Other Collider experiments • L ≈ 1031 cm-2s-1 (polarized pp) • s = 200 GeV • pp collision • x1x2 = 4×10-4 ÷ 1×10-2 • 201? • L = 1031 cm-2 s-1 • S = 30 GeV2 • ppbar collisions, e+e- final state • x1x2 = 0.2 ÷ 0.4 • YEAR 202?

  40. Drell-Yan experiments in the two next decades • European line: • COMPASS: pion beams (50-200 GeV) on polarised solid state targets (NH3 and 6LD) (>2012) • NICA SPD: proton-proton (polarised) collider (>2014) • COMPASS: antiproton beam (~100 GeV) on polarised solid state targets (NH3 and 6LD) (>2015) • PAX (GSI) polarised proton – polarised antiproton collider (>2020, if feasibility is proved) • American-Japanese line: • RHIC: polarised proton-proton collisions, √s = 200GeV • E906: proton beam(120 GeV) on unpolarised 1H, 2H, and nuclear targets (>2010) • J-Park: proton beam (30 GeV) on unpolarised target (>2010) • J-Park: polarised proton beam on (un)polarised target (>20??)

  41. Some conclusions • Next decade looks very promising for the new Drell-Yan experiments – a lot of activity in the field • The new generation of the polarised Drell-Yan programs will contribute in decisive way into our understanding of the hadron structure • Access to the valence quarks contributions as well as high luminosity seems to be an important prerequisits to the successful Drell-Yan experiment

  42. Spares

  43. Oleg Denisov

  44. WHAT ABOUT A RF SEPARATEDp BEAM ??? • First and very preliminary thoughts, guided by • recent studies for P326 • CKM studies by J.Doornbos/TRIUMF, e.g. http://trshare.triumf.ca/~trjd/rfbeam.ps.gz E.g. a system with two cavities: L RF2 RF1 DUMP DUMP Momentum selection Choose e.g. DFpp DF = 2p (L f / c) (b1-1 – b2-1) with b1-1 – b2-1 = (m12-m22)/2p2 Preliminary rate estimates for RF separated antiproton beams

  45. COMPASS wrt past DY experiments Oleg Denisov

  46. Boer-Mulders in unpolarised DY at COMPASS Flavor separation of the Boer-Mulders function from unpolarized pi- p and pi- D Drell-Yan processes.
Zhun Lu, Bo-Qiang Ma, I. Schmidt Phys.Lett.B639:494-498,2006 Oleg Denisov

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