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SoLID-Spin Program at 12 GeV JLab

SoLID-Spin Program at 12 GeV JLab. Xin Qian Kellogg Radiation Lab Caltech For SoLID Collabration. Outline. Nucleon Spin Transverse Momentum Dependent Parton Distribution Functions (TMDs) Semi-Inclusive Deep Inelastic Scattering (SIDIS)

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SoLID-Spin Program at 12 GeV JLab

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  1. SoLID-Spin Program at 12 GeV JLab XinQian Kellogg Radiation Lab Caltech For SoLIDCollabration Weihai Workshop

  2. Outline • Nucleon Spin • Transverse Momentum Dependent Parton Distribution Functions (TMDs) • Semi-Inclusive Deep Inelastic Scattering (SIDIS) • Current Status of Single Spin Asymmetry (SSA) Measurements • Overview of SoLID-Spin Program • Summary Weihai Workshop

  3. J q Nucleon Spin Structure Nucleon’s spin Ji’s Sum Rule • Understand Nucleon Spin in terms of quarks and gluons (QCD). • Small contribution from quarks and gluons’ intrinsic spin ~30% from data “spin crisis” • Orbital angular momentum is important! • Parton transverse motion + Spin-orbit correlations Weihai Workshop

  4. TMD f1u(x,kT)‏ Transverse Momentum Dependent PDFs Longitudinal Direction z Transverse Plane x-y Weihai Workshop

  5. d2kT drz d3r TMD PDFs f1u(x,kT), .. h1u(x,kT)‏ GPDs/IPDs A Unified Picture of Nucleon Structure (X. Ji) 6D Des. Wpu(x,kT,r ) Wigner distributions 3D imaging dx & Fourier Transformation d2kT d2rT Form Factors GE(Q2), GM(Q2)‏ PDFs f1u(x), .. h1u(x)‏ 1D Weihai Workshop X. Ji PRL 91 (03)‏

  6. Nucleon Spin Leading-Twist TMD PDFs Quark Spin Very well known h1= Boer-Mulders f1 = Reasonably known h1L= Worm Gear (Kotzinian-Mulders) Helicity g1 = h1= Transversity f1T= g1T= h1T= Sivers Worm Gear Pretzelosity Spin-orbital (trans. mom.) correlation is important! Weihai Workshop

  7. Semi-Inclusive DIS • A DIS reaction in which a hadron h, produced in the current fragmentation region is detected coincidently with scattered electron (k’). DXs ~ PDF X FF h tags struck quark’s flavor, spin andtransversemomentum Fragmentation function (FF)‏ h Parton distribution function (PDF)‏ Current Fragmentation Weihai Workshop

  8. Access TMDs through SIDIS Unpolarized Boer-Mulder Polarized Target Transversity/Collins Sivers Pretzelosity Polarized Beam and Target SL, ST: Target Polarization; e: Beam Polarization Weihai Workshop

  9. Separation of Collins, Sivers and pretzelocity effects through angular dependence UT: Unpolarized lepton + Transversely polarized nucleon Weihai Workshop

  10. Collins effect • Access to transversity • Transversity links quak’s spin tonucleon spin • Collins FF links quark’s spin to hadron transverse momentum • Artru model • Based on LUND fragmentation picture. Weihai Workshop

  11. Rich Physics in TMDs (Sivers Function) • Correlation between nucleon spin with quark orbital angular momentum Burkhardt : chromodynamic lensing Important test for Factorization Final-State-Interaction Weihai Workshop

  12. Current Status on TMD • Collins Asymmetries • - Sizable for proton (HERMES and COMPASS) • Large at high x, large for - but with opposite sign • Unfavored Collins fragmentation as large as favored (opposite sign) Also see Belle's data. • - consistent with 0 for deuteron (COMPASS) • - small for neutron (JLab Hall A) • Sivers Asymmetries • - non-zero for + from proton (HERMES), consistent with COMPASS results at high Q2? • - consistent with zero for - from proton and for +and - from deuteron • - negative values for neutron + , small for - (Hall A) • Very active theoretical and experimental study • RHIC-spin, JLab (CLAS12, HallA/C 12 GeV), Belle, FAIR (PAX)Future EIC • Global Fits/models by Anselmino et al., Yuan et al. and … Weihai Workshop

  13. E06010: arXiv: 1106.0363, PRL in press See X. Jiang’s talk Weihai Workshop

  14. SoLID Setup for SIDIS on 3He • High 1036 N/cm2/spolarized luminosity • Achieved Performance: • Transverse/Vertical andLongitudinal PolarizedTarget • >60% polarization • Fast Spin Flip • Large acceptanceenables 4-D mappingof asymmetries • Full azimuthal-anglecoverage -> smaller systematic uncertainties Effective pol. neutron target ~90% ~1.5% ~8% Weihai Workshop

  15. SoLID Setup for SIDIS on 3He • Tracking: GEM Tracker. • Shared R&D with Super BigBite • Electron Identification: • E&M calorimeter for large angle and high momentum • E&M calorimeter and light gas Cerenkov for forward angle • Pion identification: • Heavy Gas Cerenkov and TOF (Multi-Resistive Plate Chamber) • Fast pipeline DAQ (Similar to Hall D) • See Z. W. Zhao’s talk for simulation Progressive Tracking, Mom. res. 1%, polar angular res. 0.3 mr, azimuthal angular res. 5 mr, 0.8 cm vertex res with realistic magnetic field simulation and 200 um GEM pos. res. Shoot for 100 ps TOF resolution, (60 ps intrinsic resolution from MRPC) Weihai Workshop

  16. SIDIS L.-G. Cherenkov: Optical system One spherical mirror • Focusing optimized for central ray: • for SIDIS kinematics (BaBar) => (9.3 + 14.3)/2 = 11.8 deg Slide from S. Malace Weihai Workshop

  17. SIDIS L.-G. Cherenkov: Focusing • “F-scan”: at fixed polar angle check collection efficiency as a function of the azimuthal angle Example: 14.3 deg & 3.5 GeV Example: 14.3 deg & 1.5 GeV • Collection efficiency dependence of F: small effect at isolated kinematics Slide from S. Malace Weihai Workshop

  18. Choice of Calorimeter Typical PbSciFi Hertzog, NIM, 1990 • Two main choices • High resolution, radiation hardness, 100ps timing • SciFi ECal • Simulation shown in last meeting • W-Ecal resolution is not enough • Pb-Ecal (with >50% SciFi ratio) works • Require large area light readout • Not cheap • Shashlik Type • Pickup/Readout photon with wave-length shifting fiber, small light read out area Typical Shashlik Polyakov, COMPASS Talk, 2010 Talk from J. Huang Weihai Workshop

  19. Scan for best shower and preshower thickness Electron Efficiency Electron Efficiency Total rad length 1/ (Pi rejection) Minimal is best No preshower separation Reach Best rejection @ 3~5rad length Reach Best rejection @ ~20 rad length Can not contain EM shower More hadron shower Total rad length Total rad length Weihai Workshop Talk from J. Huang

  20. Ben Raydo Talk • L2: additional detector, simple pattern match https://www.jlab.org/exp_prog/electronics/trigdaq/PipelineTriggerElectronics_S&T09.pdf Weihai Workshop

  21. L3 Farm (slide from A. Camsonne) blocked event fragments partially recombined event fragments full events • All nodes connected with 1GB/s links • Switches connected with 10GB/s fiber optics ROC EB1 Event Builder stage 1 L3 Farm ROC EB2 Event Builder stage 2 node ROC node ROC node EB1 Event Builder stage 1 ER Event Recorder Read Out Controllers ROC Raid Disk ROC EB2 Event Builder stage 2 node node node ROC node EB1 Event Builder stage 1 ROC ROC Level-3 Trigger and monitoring Front-End Crates Staged Event Building Event Recording ~60 crates ~50MB/s out per crate N x M array of nodes (exact number to be determined by available hardware at time of purchase) 300MB/s in 300MB/s out Weihai Workshop

  22. Natural Extension of E06-010 • Both transverse and longitudinal polarized target. • Attack 6/8 leading twist TMDs • Much wider phase space • Also data at low and high z value to access target frag. and exclusive channels. Weihai Workshop

  23. h1T = Transversity • The third PDFs in addition to f1 and g1L • 10% d quark tensor charge with world data • Test Soffer’s inequality |h1T| <= (f1+g1L)/2 at large x Weihai Workshop

  24. Map Collins, Sivers and Pretzlosity asymmetries in a 4-D (x, z, Q2, PT) Weihai Workshop

  25. f1T= Sivers Function • Correlation between nucleon spin with quark angular momentum • Important test for factorization • Different sign with twist-3 quark-gluon corr. dis. at high PT? • Kang, Qiu, Vogelsang and Yuan: arxiv: 1103.1591 • Search for sign change, also PT weighted moments (Boer, Gamberg, Musch) Also in x Weihai Workshop

  26. h1T= Pretzlosity: • Direct measurement of relativistic effect of quark? PRD 78, 114024 (2008) • Direct measurement of OAM? PRD 58, 096008 (1998) • First non-zero pretzlosity asymmetries? Weihai Workshop

  27. Worm-gear functions: h1L= • Dominated by real part ofinterference between L=0 (S) and L=1 (P) states • No GPD correspondence • Lattice QCD -> Dipole Shift in mom. space. • Model Calculations -> h1L =? -g1T • Connections with Collinear PDFs through WW approx. and LIR. Worm Gear Center of points: g1T= Weihai Workshop

  28. SIDIS Factorization Test at 11 GeV • With proton/deuteron/3He unpolarized data in a large phase space coverage. • Understand SIDIS process (Factorization , PT dependence) • Complementary to Hall C RSIDIS, PT dependence studies. • Complementary to Hall B SIDIS, PT dependence studies. • Understand the Nuclear effect in the light nuclei. Weihai Workshop

  29. A New Proposal of TSSA Measurement of a Transversely Polarized Proton (NH3) • PAC report for 3He SoLID-Spin Proposal • 3 cm long NH3 target • 1035 N/cm2/s polarized luminosity • 5 T holding field • line of flames • Optics property of magnetic field 70% Polarization Weihai Workshop

  30. Projections @ 120 days About a factor of 4-5 worse than neutron measurement due to lower luminosity and larger dilution, but asymmetry is also larger with proton Weihai Workshop

  31. Bright Future for TMDs • Golden channel of Electron-Ion Collider • See Abhay Despande’s talk • Sea quark TMDs Gluon Sivers? What happened at very low x? SIDIS vs. dipole model • Test Collins-Soper Evolution for high vs. low Q2 at large x. Weihai Workshop

  32. Summary • SIDIS is a powerful tool to study Parton dynamics in the amplitude level (TMDs) • Spin-OAM correlation, flavor dependence etc. • SoLID is an ideal device to study SIDIS • High luminosity, large acceptance and full azimuthal coverage • Will provide ultimate precision (4-D) of SSA/DSA, at high-x (valence), low Q2 region, which is crucial input to global analysis. • Test SIDIS factorization, PT dependence at JLab12 (complementary to SIDIS programs in Hall B/C) Weihai Workshop

  33. Weihai Workshop

  34. Quark Tagging Technique u quark dominated Sensitive to d quark u quark dominated u quark dominated Sensitive to d quark Sensitive to u quark Weihai Workshop

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