SoLID-Spin Program at 12 GeV JLab Xin Qian Kellogg Radiation Lab Caltech For SoLID Collabration 1Weihai Workshop

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 2Weihai Workshop

Nucleon Spin Structure Understand Nucleon Spin in terms of quarks and gluons (QCD). – Small contribution from quarks and gluons’ intrinsic spin ~30% from data “spin crisis” Nucleon’s spin Ji’s Sum Rule J q Orbital angular momentum is important! Parton transverse motion + Spin-orbit correlations Weihai Workshop3

Transverse Momentum Dependent PDFs TMD Nucleon Spin QCD Dyna mics Quark OAM/ Spin QCD Factoriz ation 3-D Tomogr aphy Lattice QCD Models TMD f 1 u (x,k T ) ‏ Longitudinal Direction z Transverse Plane x-y 4Weihai Workshop

A Unified Picture of Nucleon Structure (X. Ji) W p u (x,k T,r ) Wigner distributions PDFs f 1 u (x),.. h 1 u (x)‏ d2kTd2kT d3rd3r TMD PDFs f 1 u (x,k T ),.. h 1 u (x,k T )‏ X. Ji PRL 91 (03)‏ 3D imaging 6D Des. Form Factors G E (Q 2 ), G M (Q 2 )‏ GPDs/IPDs d 2 k T dr z d2rTd2rT dx & Fourier Transformation 1D 5Weihai Workshop

Leading-Twist TMD PDFs f 1 = f 1T  = Sivers Helicity g 1 = h1 =h1 = Transversity h1 =h1 =Boer-Mulders h 1T  = Pretzelosity g 1T = Worm Gear h 1L  = Worm Gear (Kotzinian-Mulders) Nucleon Spin Quark Spin Spin-orbital (trans. mom.) correlation is important! Very well known Reasonably known Weihai Workshop6

Semi-Inclusive DIS A DIS reaction in which a hadron h, produced in the current fragmentation region is detected coincidently with scattered electron (k’). Parton distribution function (PDF)‏ Fragmentation function (FF)‏ DXs ~ PDF X FF h tags struck quark’s flavor, spin and transverse momentum Current Fragmentation h Weihai Workshop7

Access TMDs through SIDIS S L, S T : Target Polarization; e : Beam Polarization Unpolarized Polarized Target Polarized Beam and Target Boer-Mulder Sivers Transversity /Collins Pretzelosity Weihai Workshop8

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

Collins effect Access to transversity – Transversity links quak’s spin to nucleon spin – Collins FF links quark’s spin to hadron transverse momentum Artru model – Based on LUND fragmentation picture. Weihai Workshop10

Rich Physics in TMDs (Sivers Function) Correlation between nucleon spin with quark orbital angular momentum Burkhardt : chromodynamic lensing Final-State-Interaction Important test for Factorization Weihai Workshop11

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 Q 2 ? - 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 … 12Weihai Workshop

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

High N/cm 2 /s polarized luminosity Achieved Performance: – Transverse/Vertical and Longitudinal Polarized Target – >60% polarization – Fast Spin Flip Large acceptance enables 4-D mapping of asymmetries Full azimuthal-angle coverage -> smaller systematic uncertainties SoLID Setup for SIDIS on 3 He ~90% ~1.5% ~8% Effective pol. neutron target 14Weihai Workshop

SoLID Setup for SIDIS on 3 He 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) 15Weihai Workshop

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

SIDIS L.-G. Cherenkov: Focusing  “  -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  : small effect at isolated kinematics Slide from S. Malace 17Weihai Workshop

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 Weihai Workshop18 Choice of Calorimeter Typical Pb SciFi Hertzog, NIM, 1990 Typical Shashlik Polyakov, COMPASS Talk, 2010 Talk from J. Huang

Weihai Workshop19 Scan for best shower and preshower thickness Reach Best 3~5rad length Total rad length No preshower separation Electron Efficiency 1/ (Pi rejection) Minimal is best Reach Best ~20 rad length Total rad length Can not contain EM shower More hadron shower Electron Efficiency Talk from J. Huang

L2: additional detector, simple pattern match Ben Raydo Talk 20Weihai Workshop

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

Natural Extension of E 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. 22Weihai Workshop

Transversity The third PDFs in addition to f 1 and g 1L 10% d quark tensor charge with world data Test Soffer’s inequality |h 1T | <= (f 1 +g 1L )/2 at large x h 1T = 23Weihai Workshop

Map Collins, Sivers and Pretzlosity asymmetries in a 4-D (x, z, Q 2, P T ) 24Weihai Workshop

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 P T ? – Kang, Qiu, Vogelsang and Yuan: arxiv: – Search for sign change, also P T weighted moments (Boer, Gamberg, Musch) f 1T  = Also in x 25Weihai Workshop

Pretzlosity: Direct measurement of relativistic effect of quark? PRD 78, (2008) Direct measurement of OAM? PRD 58, (1998) First non-zero pretzlosity asymmetries? h 1T  = 26Weihai Workshop

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

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

A New Proposal of TSSA Measurement of a Transversely Polarized Proton (NH 3 ) PAC report for 3He SoLID-Spin Proposal Weihai Workshop29 3 cm long NH 3 target N/cm 2 /s polarized luminosity 5 T holding field line of flames Optics property of magnetic field 70% Polarization

120 days Weihai Workshop30 About a factor of 4-5 worse than neutron measurement due to lower luminosity and larger dilution, but asymmetry is also larger with proton

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 Q 2 at large x. 31Weihai Workshop

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 Q 2 region, which is crucial input to global analysis. – Test SIDIS factorization, P T dependence at JLab12 (complementary to SIDIS programs in Hall B/C) 32Weihai Workshop

33

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