SoLID SIDIS UpdateZhiwen Zhao

University of Virginia

For SoLID Collaboration

Hall A Collaboration Meeting2013/12/17

2SoLID (Solenoidal Large Intensity Device)General purpose device, large acceptance, high luminosity

Lumi 1e37/cm2/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 1e39/cm2/s (baffled geometry)Standard Model test and hadron structure

PVDIS on both deuterium and hydrogen (1 EXP)

High rateHigh doseHigh field

3

Quark polarization

Unpolarized(U)

Longitudinally Polarized (L)

Transversely Polarized (T)

Nucleon Polarization

U

L

T

Leading-Twist TMD PDFs

f1 =

f 1T =

Sivers

Helicityg1 =

h1 =Collins/Transversity

h1 =

Boer-Mulders

h1T =

Pretzelosity

g1T =

Worm Gear

h1L =

Worm Gear

Nucleon Spin Quark Spin

4Semi-Inclusive DIS (SIDIS)

TMD

Nucleon Spin

QCD Dynamics

Quark OAM / Spin

QCD Factorizatio

n

3-D Tomograph

y

Lattice QCD

Models

Precision mapping of transverse momentum dependent parton distributions (TMD)

1( , )

sin( ) sin( )

sin(3 )

l lUT h S

h SSiverCollins

Pretzelosi

UT

tyU

sUT h S

h ST

N NA

P N

A

A

N

A

TMD links:1. Nucleon spin2. Parton spin3. Parton intrinsic

motion

5SoLID: 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┴,Q2) Multi-facilities, global effort

Precision high statistics high luminosity large acceptance

E12-10-006: SIDIS on transversely polarized 3He @ 90 daysE12-11-007: SIDIS on Longitudinally polarized 3He @ 35 daysLOI-12-13-002: Dihadron SIDIS on transversely polarized 3HeE12-11-108: SIDIS on transversely polarized proton @ 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

7Requirement of SIDIS

Kinematics Coverage: 0.05 ~ 0.6 in x (valence) 0.3 ~ 0.7 in z (factorization region) PT up to ~ 1 GeV (TMD Physics) Fixed target Q2 coverage 1-8 GeV2 (~ 2 GeV2 in

ΔQ2 at fixed x) Luminoisity:

3He Unpolarized ~ 1037 N/cm2/s NH3 Unpolarized ~ 1036 N/cm2/s

Polarized 3He Target: ~ 60% higher polarization Fast spin flip (<20 mins)

Polarized NH3 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

8Radiation and Luminosity EstimationPVDIS SIDIS He3

Beam 50uA 15uA

Target LD2 40cm 10amg He3 40cm

Window Al 2*100um Glass 2*120um

Radiation length (target) 5.4e-2 0.8e-3

Radiation length (window) 2.25e-3 3.4e-3

Radiation length (total) 5.6e-2 4.2e-3

Luminosity (target) 1.27e39 3e36

Luminosity (window) 1e37 3.7e36

Luminosity (total) 1.27e39 6.7e36

Comment baffle target window collimator

Updated simulation with full background

9SIDIS 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

targetcollimator

Zhiwen Zhao, Xin Qian

10SIDIS He3 Electron TriggerDIS electron (Q2>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 Q2=1

• LAEC: Trigger at 3GeV

Jin Huang, Zhiwen Zhao

Pion trigger eff. VS Mom

Electron/photon trigger eff. VS Mom

1GeV 2GeV 3GeV 4GeV 5GeV

1GeV 2GeV 3GeV 4GeV 5GeV

11SIDIS 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

backgroundTrigger eff. VS Mom

electron photon

pion proton

Jin Huang, Zhiwen Zhao

12SIDIS 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

13SIDIS He3 LGCC Background Rate Low energy background

rate 6.6MHz Hadron (from target)

accidental rate 2MHz

Michael Paolone

14SIDIS 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 forcharged particle (blue) and gamma (red)

Energy deposit in SPD forelectron (blue), pion (red) and gamma (black)

Zhihong Ye, Jin Huang, Zhiwen Zhao

15SIDIS 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

16SoLID HGCC Design Update

Mehdi Meziane

17SoLID 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

/ (1 ) : 0 1G PCJ S I J / 3.097JM GeV Gluon Study Using J/ψ

?

19SoLID J/ψ Setup (E12-12-006)

• 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+)

20DVCS and TCS: access the same GPDs

20

Spacelike Deeply Virtual Compton Scattering Timelike 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

21SoLID TCS Setup (LOI-12-13-001)

• 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+)

22Summary

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