SoLID SIDIS Update Zhiwen Zhao University of Virginia For SoLID Collaboration Hall A Collaboration Meeting 2013/12/17

2 SoLID (Solenoidal Large Intensity Device) General purpose device, large acceptance, high luminosity Lumi 1e 37 /cm 2 /s (open geometry)  3D hadron structure  TMD (SIDIS on both neutron and proton) (3 EXPs, 1 LOI)  GPD (Timelike Compton Scattering) (1 LOI)  Gluon study  J/  production at threshold (1 EXP) Lumi 1e 39 /cm 2 /s (baffled geometry)  Standard Model test and hadron structure  PVDIS on both deuterium and hydrogen (1 EXP) High rate High dose High field

3 Leading-Twist TMD PDFs f 1 = f 1T  = Sivers Helicity g 1 = h1 =h1 = Collins/Transversity h1 =h1 =Boer-Mulders h 1T  = Pretzelosity g 1T = Worm Gear h 1L  = Worm Gear Nucleon Spin Quark Spin

4 Semi-Inclusive DIS (SIDIS) TMD Nucleon Spin QCD Dynami cs Quark OAM / Spin QCD Factoriz ation 3-D Tomogr aphy Lattice QCD Models Precision mapping of transverse momentum dependent parton distributions (TMD) TMD links: 1.Nucleon spin 2.Parton spin 3.Parton intrinsic motion

5 SoLID: Precision Study of TMDs  From exploration to precision study with 12 GeV JLab  Transversity: fundamental PDFs, tensor charge  TMDs: 3-d momentum structure of the nucleon   Quark orbital angular momentum  Multi-dimensional mapping of TMDs  4-d (x,z,P ┴,Q 2 )  Multi-facilities, global effort  Precision  high statistics  high luminosity  large acceptance E : SIDIS on transversely polarized 3 90 days E : SIDIS on Longitudinally polarized 3 35 days LOI : Dihadron SIDIS on transversely polarized 3 He E : SIDIS on transversely polarized 120 days

6  Tracking: GEM Tracker  Electron Identification: Large angle EM calorimeter (LAEC) including Scintillator Pad Detector (SPD) Forward angle EM calorimeter (FAEC) including Scintillator Pad Detector (SPD) Light Gas Cerenkov (LGCC)  Pion identification: Heavy Gas Cerenkov (HGCC) TOF (MRPC) SoLID SIDIS Setup

7 Requirement of SIDIS  Kinematics Coverage:  0.05 ~ 0.6 in x (valence)  0.3 ~ 0.7 in z (factorization region)  P T up to ~ 1 GeV (TMD Physics)  Fixed target  Q 2 coverage 1-8 GeV 2 (~ 2 GeV 2 in ΔQ 2 at fixed x)  Luminoisity:  3 He Unpolarized ~ N/cm 2 /s  NH 3 Unpolarized ~ N/cm 2 /s  Polarized 3 He Target:  ~ 60% higher polarization  Fast spin flip (<20 mins)  Polarized NH 3 Target:  Jlab/UVa target with upgraded design of the magnet  Spin flip every two hours average  ~70% in-beam polarization  Beamline chicane to transport beam through 5T target magnetic field  Electron PID:  <1% Pion contamination (asymmetry point of view)  Pion PID:  <1% Kaons and Protons  <1% electron contamination  Optics of Reconstruction:  < a few % in δP/P  < 1 mr in polar angle  < 10 mr in azimuthal angle  ~ 1-2 cm vertex resolution  DAQ:  ~ 3kHz physics coincidence  < 100 kHz coincidence rate  Limits: 300 MB/s to tape

8 Radiation and Luminosity Estimation PVDISSIDIS He3 Beam50uA15uA TargetLD2 40cm10amg He3 40cm WindowAl 2*100umGlass 2*120um Radiation length (target)5.4e-20.8e-3 Radiation length (window)2.25e-33.4e-3 Radiation length (total)5.6e-24.2e-3 Luminosity (target)1.27e393e36 Luminosity (window)1e373.7e36 Luminosity (total)1.27e396.7e36 Commentbaffletarget window collimator Updated simulation with full background

9 SIDIS He3 Target Collimator  A pair of collimators are optimized to block background from both target windows into forward angle detectors  The acceptance without (black) and with (red) the collimators target collimator Zhiwen Zhao, Xin Qian

10 SIDIS He3 Electron Trigger DIS electron (Q 2 >1, W>2) acceptance on FAEC with SoLID CLEO magnet and 40cm target FAEC: Radius and momentum dependent trigger threshold to select DIS electron by cutting on the line of Q 2 =1 LAEC: Trigger at 3GeV Jin Huang, Zhiwen Zhao Pion trigger eff. VS Mom Electron/photon trigger eff. VS Mom 1GeV2GeV3GeV4GeV5GeV 1GeV2GeV3GeV4GeV5GeV

11 SIDIS He3 Charged Particle Trigger  FAEC only, pion rate drops very quickly at large angle  Cut on MIP only to preserve pions and suppress low energy background Trigger eff. VS Mom electronphoton pion proton Jin Huang, Zhiwen Zhao

12 SIDIS He3 EC Trigger Rate  Need photon suppression by LGCC, SPD and MRPC  Need pion suppression by LGCC  Some of electrons and positrons from the pair production of gamma from pi0 decay can be suppressed by LGCC,SPD or MRPC depending on where the conversion happens Jin Huang, Zhiwen Zhao

13 SIDIS He3 LGCC Background Rate  Low energy background rate 6.6MHz  Hadron (from target) accidental rate 2MHz Michael Paolone

14 SIDIS SPD and MRPC Photon Rejection  SPD or MRPC alone can reach 10:1 rejection  Combined together, they can reach ~ 20:1 rejection due to their correlation Fired layer count in MRPC for charged particle (blue) and gamma (red) Energy deposit in SPD for electron (blue), pion (red) and gamma (black) Zhihong Ye, Jin Huang, Zhiwen Zhao

15 SIDIS He3 Trigger rate  Forward angle electron trigger rate, combining FAEC,SPD,MRPC and LGCC, 140kHz  Large angle electron trigger rate, combining LAEC and SPD, 20kHz  Forward angle charged particle trigger rate, combining FAEC,SPD and MRPC, 18.7MHz  Total coincidence rate ~ 90kHz with 30ns time window

16 SoLID HGCC Design Update Mehdi Meziane

17 SoLID GEM Test at Fermi Lab  1m long GEM (largest in the world) for SoLID built at UVa  Successfully tested with APV25/SRS readout at Fermi Lab in Oct 2013 Kondo Gnanvo

18  J/ψ, a charm-anti-charm system  Little (if not zero) common valence quark between J/ψ and nucleon  Quark exchange interactions are strongly suppressed  Pure gluonic interactions are dominant  J/ψ, a probe of the strong color field in the nucleo  Multiple gluon exchange possible near threshold  Not much data available at that region 18 Gluon Study Using J/ψ ?

19 SoLID J/ψ Setup (E ) Detect decay e - e + pair Detect (or not) scattering e for electroproduction (or photoproduction) Detect recoil p to be exclusive e p → e ′ p′ J/ψ(e - e + ) γ p → p′ J/ψ(e - e + )

20 DVCS and TCS: access the same GPDs 20 Spacelike Deeply Virtual Compton ScatteringTimelike Compton Scattering γ p → γ*(e - e + ) p′ γ*p → γ p′ Information on the real part of the Compton amplitude can be obtained from photoproduction of lepton pairs using unpolarized photons

21 SoLID TCS Setup (LOI ) Detect decay e - e + pair Detect recoil p to be exclusive Cut on missing momentum and mass to ensure quasi-real process γ p → p′ γ* (e - e + ) e p → e ′ p′ γ* (e - e + )

22 Summary  We have made good progress and are ready for the director review in early next year  SoLID SIDIS setup is a general device. More experiments may be proposed to take advantage of its large acceptance and high luminosity features