Physics Ideas

Study of Exclusive Hard Processes with Hadron Beams at J-PARCMini Workshop on Structure and Productions of Charmed Baryons IIAugust 7-9, 2014, J-PARC, TokaiWen-Chen Chang Institute of Physics, Academia Sinica

1OutlineUniqueness of hadron physics studied at HiPBL of J-PARCSelected Physics Processes:Drell-Yan processHard exclusive processFeasibility study of exclusive Drell-Yan process in P50 spectrometerSummary223High-res., High-momentum Beam LineHigh-intensity secondary Pion beam

High-resolution beam: Dp/p~0.1%

Dispersive Focal Point (DFP)Dp/p~0.1%Collimator15kW Loss Target(SM)

Exp. Target (FF)Pion BeamUp to 20 GeV/c H. NoumiLet me start from this naive question in hadron physics;What are good building blocks of hadrons?We know that a constituent quark is a very good building block of hadrons, which successfully describes hadron properties, such as masses, classifications based on spin/flavor symmetry, and even magnetic moments. This is good for ground state hadrons.However, the constituent quark model sometimes fails in resonance states.Hadrons can be good building blocks, as recently Meson-meson and Meson-Baryon molecular states are intensively discussed. Here, they are all color singlet states.

Diquark is considered as a building block of baryons.Although this object is discussed for a long time. it has not been settled yet.34High-res., High-momentum Beam LineHigh-intensity secondary Pion beam>1.0 x 107 pions/sec @ 20GeV/cHigh-resolution beam: Dp/p~0.1%* Sanford-Wang:15 kW Loss on Pt, Acceptance :1.5 msr%, 133.2 mOpen a new platform for hadron physics Prod. Angle = 0 deg. (Neg.)p-K-pbarp+K+ Prod. Angle = 3.1 deg (Pos.)H. NoumiPrimary 30-GeV proton beam at 1010-1012/s.Secondary beam:Pion: 10-20 GeV at 107-108/s .Kaon: 10-15 GeV at 106-107/s. Anti-proton: 5-10 GeV at 106/s.4

http://www-conf.kek.jp/hadron1/j-parc-hm-2013/5

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http://j-parc-th.kek.jp/workshops/2014/02-10/

Uniqueness of hadron physics studied at HiPBL of J-PARCThe beam energy at J-PARC at 10-20 GeV might be most ideal for studying the hard exclusive processes and discerning the quark-hadron transition in the strong interaction.Valance-like partonic degrees of freedom of hadrons could be discerned, compared to the collisions at low-energy regime.Reasonably large cross sections, compared to the collisions at higher energy.7Constituent-Counting Rule in Hard Exclusive Process Kawamura et al., PRD 88, 034010 (2013)

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Selected Physics ProcessesDrell-Yan processInclusive pion-induced Drell-YanExclusive pion-induced Drell-YanHard exclusive production processExclusive pion-N Lambda(1405) production (Sekiharas talk)Charm production processInclusive pion-induced J/psi productionExclusive pion-N J/psi productionExotic charmed baryons (this workshop)

9Drell-Yan process10

Wigner Distribution11Wigner Distributiond3r Transverse Momentum Dependent PDFGeneralized Parton Distr.

d2ktdzF.T.d2kt PDFdx Form Factors

GPDJi, PRL91,062001(2003)

Then, the function Wn(x, p) corresponds to the classical trajectory in the phase space given by the coordinates xand p. Therefore, the delocalization of the Wigner distribution indicates quantum effects due to the uncertaintyprinciple. The Wigner distribution provides information on quantum states by using the phase-space concept.11

u valencesea (x 0.05)gluon (x 0.05)d Unpolarized Parton Distributions (CTEQ6)12

DIS, Valance quarks at large x and gluon, sea quarks at small x, what is the origin of sea quark1213Is in the proton?

Gottfried Sum Rule

=

Gluon splitting. GSR, =1/3 if ubar(x)=dbar(x)1314Experimental Measurement of Gottfried Sum

New Muon Collaboration (NMC), Phys. Rev. D50 (1994) R1SG = 0.235 0.026( Significantly lower than 1/3 ! )

S. Kumano, Physics Reports, 303 (1998) 183Experimental test of this sum rule using DIS exp deviates from 1/31415

Light Antiquark Flavor Asymmetry: Drell-Yan ExpsNave Assumption:NA51 (Drell-Yan, 1994)

NMC (Gottfried Sum Rule)NA 51 Drell-Yan confirms d(x) > u(x)

15Drell-Yan process where quark and antiquark from colliding hadrons annihlnate into virtual photon and then decaying into di-lepton offer the chance of looking the x-dependence of ubar and dbar difference beyond the x-integrated value.NA51 is the first one, confirming dbar>ubar at x=0.1816

Light Antiquark Flavor Asymmetry: Drell-Yan ExpsNave Assumption:NA51 (Drell-Yan, 1994)E866/NuSea (Drell-Yan, 1998)

NMC (Gottfried Sum Rule)

16Following E866 exp provides more detailed information of this x-dependence.Origin of u(x)d(x)?Pauli blocking of valance quarksMeson cloud in the nucleons (Thomas 1983, Kumano 1991): Sullivan process in DIS.

Chiral quark model (Eichten et al. 1992; Wakamatsu 1992): Goldstone bosons couple to valence quarks.17

Origin of dbar and ubar difference could be accounted by pauli blocking effect or meson cloud around the nucleon. However, there is tentative sign of ubar>dbar at large x.17Momentum Dependence of the Flavor Structure of the Nucleon SeaJ.-C. Peng, W.-C. Chang, H.-Y. Cheng, T.-J. Hou, K.-F. Liu, J.-W. Qiu, arXiv:1401.170518

JR14NMC

Fluctuation of a valence quark into a quark and a highly virtual gluon, A quick splitting of the gluon into a quark and antiquark pairAnnihilation or recombination of the quark and the newly produced antiquark into a highly virtual gluon, which is thenAbsorbed by the quark.19

Momentum Dependence of the Flavor Structure of the Nucleon SeaJ.-C. Peng, W.-C. Chang, H.-Y. Cheng, T.-J. Hou, K.-F. Liu, J.-W. Qiu, arXiv:1401.170520

Extracting d-bar/-ubar From Drell-Yan ScatteringRatio of Drell-Yan cross sections

(in leading orderE866 data analysis confirmed in NLO)Global NLO PDF fits which include E866 cross section ratios agree with E866 resultsFermilab E906/Drell-Yan will extend these measurements and reduce statistical uncertainty.E906 expects systematic uncertainty to remain at approx. 1% in cross section ratio.

Flavor Structure of the Nucleon SeaW.-C. Chang and J.-C. Peng, arXiv:1406.126020To precisely measure dbar and ubar difference at large-xA. Accardiet al.Phys. Rev. D 84, 014008 (2011)

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Deuteron wave function at short distances (Fermi motion)Nucleon off-shell effectNuclear correction

22J.C. Peng

Helium/DME at 80/20 ratiobeam140 mExperimental Setup II: BoNuS RTPCFit RTPC points to determine helix of proton trajectory.

Momentum determined from track curvature in solenoid field.

dE/dx along track in RTPC also provides momentum information.

SolenoidMagnetBoNuSRTPCMoller Catcher To BoNuS RTPCto CLAS

pnM. Eric Christy2323Neutron F2 Structure Function via Spectator TaggingPRL 108, 142001 (2012)

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Pion-Induced DY Without OR With Spectator Tagging25

Wigner Distribution26Wigner Distributiond3r Transverse Momentum Dependent PDFGeneralized Parton Distr.

d2ktdzF.T.d2kt PDFdx Form Factors

GPDJi, PRL91,062001(2003)

three distribution functions are necessary to describe the quark structure of the nucleon at LO in the collinear case Transverse momentum dependent (TMD) PDFtaking into account the quark intrinsic transverse momentum kT , At leading order 8 PDFs are needed.ULTULTnucleon polarizationTMDs

number density

helicity

transversity

SiversBoer-MuldersT-odd Sivers function correlation between the transverse spin of the nucleon and the transverse momentum of the quarksensitive to orbital angular momentumBoer-Mulders function correlation between the transverse spin and thetransverse momentum of the quark in unpol nucleons28quark polarization

pretzelositySivers function: correlation between nucleon transverse spin and parton transverse momentum.Boer-Mulders function: correlation between partonic transerve spin and its transverse momentum.27Global Analysis of SIDIS from HERMES and COMPASSM. Anselmino et al., Eur.Phys.J.A39:89-100,2009

28HERMES proton targetCOMPASS deuteron targetSivers Functions from SIDISM. Anselmino et al., Eur.Phys.J.A39:89-100, 2009

29uuddSign Change of Sivers & Boer-Mulders FunctionsJ.C. Collins, Phys. Lett. B 536 (2002) 43A.V. Belitsky, X. Ji, F. Yuan, Nucl. Phys. B 656 (2003) 165D. Boer, P.J. Mulders, F. Pijlman, Nucl. Phys. B 667 (2003) 201Z.B. Kang, J.W. Qiu, Phys. Rev. Lett. 103 (2009) 17200130

Drell-YanSIDISQCD gluon gauge link (Wilson line) in the initial state (DY) vs. final state interactions (SIDIS).Experimental confirmation of the sign change will be a crucial test of perturbative QCD and TMD physics.31experimentparticlesenergyx1 or x2 luminositytimelineCOMPASS(CERN)p + p160 GeVs = 17.4 GeVxt = 0.2 0.32 x 1033 cm-2 s-12014, 2018PAX(GSI)p + pbarcolliders = 14 GeVxb = 0.1 0.92 x 1030 cm-2 s-1>2017PANDA(GSI)pbar + p15 GeVs = 5.5 GeVxt = 0.2 0.42 x 1032 cm-2 s-1>2016NICA(JINR)p + pcolliders = 20 GeVxb = 0.1 0.81 x 1030 cm-2 s-1>2018PHENIX(RHIC)p + pcolliders = 500 GeVxb = 0.05 0.12 x 1032 cm-2 s-1>2018RHIC internaltarget phase-1p + p250 GeVs = 22 GeVxb = 0.25 0.42 x 1033 cm-2 s-1>2018RHIC internaltarget phase-1p + p250 GeVs = 22 GeVxb = 0.25 0.46 x 1034 cm-2 s-1>2018FNAL Pol tgt (E1039)p + p120 GeVs = 15 GeVxt = 0.1 0.453.4 x 1035 cm-2 s-12016FNAL Pol beam (E1027)p + p120 GeVs = 15 GeVxb = 0.35 0.852 x 1035 cm-2 s-12018Planned Polarized Drell-Yan ExperimentsWolfgang LorenzonKey Elements of Polarized DY Exp.:Transversely Polarized NH3 Target

32Magnet

Theoretical Predictions vs. COMPASS Expected Precision33SiversSiversBoer-MuldersBoer-MuldersBMPretze.BMtransvBMPretze.BMtransvWe have good enough sensitivity for the predicted Sivers function at low and high mass regions.33three distribution functions are necessary to describe the quark structure of the nucleon at LO in the collinear case Transverse momentum dependent (TMD) PDFtaking into account the quark intrinsic transverse momentum kT , At leading order 8 PDFs are needed.ULTULTnucleon polarizationTMDs

number density

helicity

transversity

SiversBoer-MuldersT-odd Sivers function correlation between the transverse spin of the nucleon and the transverse momentum of the quarksensitive to orbital angular momentumBoer-Mulders function correlation between the transverse spin and thetransverse momentum of the quark in unpol nucleons35quark polarization

pretzelositySivers function: correlation between nucleon transverse spin and parton transverse momentum.Boer-Mulders function: correlation between partonic transerve spin and its transverse momentum.34Angular Distribution of Lepton Pair

Collins-Soper Frame35Lam and Tung (PRD 18, 2447, (1978))Lam-Tung Relation36

E615 (PRD 39, 92 (1989)) Violation of LT Relation in -induced Drell-Yan Process

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D. Boer38

D. Boer

39Boer (PRD 60, 014012 (1999))Hadronic Effect, Boer-Mulders Functions

40E866 (PRL 99 (2007) 082301) Azimuthal cos2 Distribution of DY events in pd(-W+-X)~ [valence h1()] * [valence h1(p)](pd+-X) ~ [valence h1(p)] * [sea h1(p)] Sea-quark BM functions are much smaller than valence quarks

41Boer-Mulders functions from unpolarized pD and pp Drell-YanZ. Lu and I. Schmidt,PRD 81, 034023 (2010)

V. Barone et al.,PRD 82, 114025 (2010)

Sign of BM functions and their flavor dependence?42Flavor separation of the BoerMulders functionZ. Lu et al. (PLB 639 (2006) 494)

MIT Bag ModelSpectator ModelLarge Nc limitDeuterium target43Wigner Distribution44Wigner Distributiond3r Transverse Momentum Dependent PDFGeneralized Parton Distr.

d2ktdzF.T.d2kt PDFdx Form Factors

GPDJi, PRL91,062001(2003)

x+xx-xtGPDsPP

Jis sum ruleGeneralized Parton Distribution (GPD)

4545

Spacelike vs. Timelike ProcessesMuller et al., PRD 86 031502(R) (2012)

46Deeply Virtual Compton ScatteringTimelike Compton Scattering

Spacelike vs. Timelike ProcessesMuller et al., PRD 86 031502(R) (2012)

47Deeply Virtual Meson ProductionExclusive Meson-induced DY

N+-N(PLB 523 (2001) 265)

48N+-N(PLB 523 (2001) 265)

49Pion-pole Dominance

50

Pion-pole Dominance (PLB 523 (2001) 265)

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N+-N (PLB 523 (2001) 265)52

Cross sections increase toward small s!J-PARC

|t| (GeV2)

N+-N: |t| and Q (M) dependence53

|t| (GeV2)Total Cross Sections of Exclusive Drell-Yan as a function of momentum of Beam54

M > 1.5 GeV10 pbGPD(xB,Q2) in space-like regime

55GPD(xB,Q2) in both space-like and time-like regime

56J-PARCs results in the time-like and large-Q2 region will be complementary to what to be obtained in space-like region from the deeply virtual Compton scattering (DVCS) deeply virtual meson scattering (DVMS) process to be measured in JLab.Large-Q2 regionHard exclusive production process57

Constituent-Counting Rule in Hard Exclusive ProcessKawamura et al., PRD 88, 034010 (2013)

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Quark Degrees of (1405)Kawamura et al., PRD 88, 034010 (2013)

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1-100 pbT. Sekiharas talkJ-PARCExperimental Difficulties60

Charmed production process61

J/ production in 22 GeV Cu collisionsNucl. Phys. B179 (1981) 189

62(N)(pN): gg fusion dominates

J/-N Interaction StrengthWu and Lee, PRC 88, 015205 (2013)

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J-PARCJ/-N Interaction StrengthWu and Lee, PRC 88, 015205 (2013)

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Look for production of hidden charm bound state. arXiv:1212.2440108/secSimilar interesting physics to be explored by other secondary beams like K and pbar.Target: Long liquid hydrogenShort nuclei target.Detector:Open aperture without hadron absorber before momentum determination: minimize multiple-scattering of muonsSpectrometer with good momentum resolution and particle IDMuon ID in the forward direction at the very downstream70J-PARC P50 Spectrometer

71J-PARC P50 Spectrometer72

p-LH2-targetRing ImageCherenkovCounterInternal DCFM magnetps-K+Fiber trackerBeam GCInternal TOFInternal TOFDCTOF wall2mDecay p(p+)20 GeV/cBeam p-Acceptance: ~ 60% for D*, ~80% for decay p+ Resolution: Dp/p~0.2% at ~5 GeV/cRigidity ~2.1 Tm)

20 GeV -Exclusive DYx 200 eventsThanks to K. Shirotori for P50 MC framework.73J-PARC P50 Spectrometer + MuID74

p-LH2-targetRing ImageCherenkovCounterInternal DCFM magnetps-K+Fiber trackerBeam GCInternal TOFInternal TOFDCTOF wall2mDecay p(p+)20 GeV/cBeam p-Acceptance: ~ 60% for D*, ~80% for decay p+ Resolution: Dp/p~0.2% at ~5 GeV/cRigidity ~2.1 Tm)|| 1.5 GeV10 pbYield Estimation based on J-PARC P50 ParametersIbeam=107 /s, nTGT=4 g/cm2 (57cm LH2), /~100% , (DAQ, Tracking, PID)=0.9*0.7*0.9 1 events/day/pbBeam time of 200 daysInclusive pion-induced Drell-Yan: OKExclusive pion-induced Drell-Yan: Marginally OKExclusive pion-N Lambda(1405) production: OK (multi-particle acceptance?)Inclusive pion-induced J/psi production: OKExclusive pion-N J/psi production: NO

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20-GeV - + proton+-X MX seen In P-50 Spectrometer + MuID78Red: Exclusive DY ( 10 pb )Blue: Inclusive DY ( 500 pb )Green: random BG from meson decayAfter 200-day data-takingAssumption: p/p = 0.2 %Missing Mass MX (GeV2)NeventThe signal of exclusive Drell-Yan processes can be clearly identified in the missing mass spectrum of dimuon pairs.Summary (I)High-energy hadron beam at J-PARC is ideal for studying hard exclusive processes.The study of -induced DY/charm production and hard exclusive processes will offer important understanding onNucleon structure: sea quarks PDF; TMD, GPDpion structure: DA and Timelike FFStructure of exotic hadronsJ/ production mechanism, exotic charmed baryons

7979Summary (II)Spectrometer with large acceptance and good mass resolution is required for the measurement and such measurement in P-50 conceptual detectors seems promising. Availability of deuterium target together with the detection of recoiled protons will enable the measurement of flavor separation of BM functions and valance-quark distributions at large-x.8080Backup Slides81

R. Muto, KEK82

R. Muto, KEK83

R. Muto, KEK84J-PARC High-momentum Beam LineHigh-intensity secondary Pion beam>1.0 x 107 pions/sec @ 20GeV/cHigh-resolution beam: Dp/p~0.1%

85* Sanford-Wang:15 kW Loss on Pt, Acceptance :1.5 msr%, 133.2 m Prod. Angle = 0 deg. (Neg.)p-K-pbarp+K+ Prod. Angle = 3.1 deg (Pos.)Let me start from this naive question in hadron physics;What are good building blocks of hadrons?We know that a constituent quark is a very good building block of hadrons, which successfully describes hadron properties, such as masses, classifications based on spin/flavor symmetry, and even magnetic moments. This is good for ground state hadrons.However, the constituent quark model sometimes fails in resonance states.Hadrons can be good building blocks, as recently Meson-meson and Meson-Baryon molecular states are intensively discussed. Here, they are all color singlet states.

Diquark is considered as a building block of baryons.Although this object is discussed for a long time. it has not been settled yet.85

86Parton Interpretation of GPDs(Phys. Rept, 388, 41 (2003), hep-ph/0307382; arXiv:1302.2888)

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GPDGPDGPDDGLAP-II: -1