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Hall B Physics Program and Upgrade Plan

Hall B Physics Program and Upgrade Plan. Volker D. Burkert Jefferson Lab. Introduction The Equipment Plan The 12 GeV Physics Program Conclusions. PAC23 Meeting on the 12 GeV Upgrade, January 20, 2003. Physics Program with CLAS ++ at 12 GeV.

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Hall B Physics Program and Upgrade Plan

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  1. Hall B Physics Program and Upgrade Plan Volker D. Burkert Jefferson Lab • Introduction • The Equipment Plan • The 12 GeV Physics Program • Conclusions PAC23 Meeting on the 12 GeV Upgrade, January 20, 2003

  2. Physics Program with CLAS++ at 12 GeV • Quark-Gluon Dynamics and Nucleon Tomography • Deeply Virtual Compton Scattering (DVCS) • Deeply Virtual Meson Production (DVMP) • High-t DVCS and p0/h production • Valence Quark Distributions • Proton and Neutron Spin Structure • Neutron Structure Function F2n(x,Q2) • Tagged Quark Distribution Functions • Novel Quark Distribution Functions (tranversity, e(x),..) • Form Factors and Resonance Excitations • The Magnetic Structure of the Neutron • Resonance Excitation Dynamics • Hadrons in theNuclear Medium • Space-Time Characteristics of Hadronization • Color transparency • Physics withquasi-real Photons

  3. Reduce DC occupancies to reach higher luminosities • - reduce DC cell sizes • - new magnetic shielding for Moller electrons .. Requirements for the CLASupgrade: • Retain high statistics capabilities for exclusive processes at beam energies up to 12 GeV • Complement missing mass techniques by more complete detection of hadronic final state • Increase maximum luminosity to 1035cm-2sec-1 • Extend particle ID to higher momenta (e-/p-, p/K/p, g/po) • Complement CLAS detection system with new Central Detector • - tracking, magnetic analysis, and photon detection in angular • range 5o - 135o • - veto events with incomplete determination of final state • Upgrade the CLAS Forward detection system • - implement new threshold Cherenkov detector pp ~ 5 GeV/c • - improve time-of-flight resolution to ~ 60psec • - increase calorimeter granularity for po/g separation

  4. ++ The CLAS Detector Forward Cerenkov Forward EC Forward DC Inner Cerenkov Central Detector Preshower EC Forward TOF Torus Cold Ring Coil Calorimeter

  5. CLAS++ - 2D CUT ~38o ~5o repositioned torus coils

  6. ++ The CLAS Detector Central Detector TOF light guide TOF lightguide Flux return Microstrip Superconducting solenoid coil (Bmax = 5T) Central EC Central TOF Central Tracker

  7. Bz z Magnetic Field Distribution in Flux Return Iron Flux Return Iron Solenoid Coil Central B-Field 5 Tesla (Gauss)

  8. .. Moller Electrons in Target Region L=1035cm-2s-1, DT = 250nsec without solenoid field 5 Tesla with solenoid field .. Moller electrons are contained within a 3o cone around the beam.

  9. axial readout prototype under construction with 5,500 fibers ++ CLAS Central Calorimeter Axial fibers Tungsten-SciFi PMTs Polar angle fibers Fiber readout

  10. additional particle id from DEscint ++ The CLAS Detector Central Time-of-Flight Detector TOF Lightguide Flux return TOF Lightguide Central TOF scintillator

  11. ++ The CLAS Detector Central Drift Chamber - Cathode Pad Readout Outer cathode plane Cathode Pad Layer Cathode Pad Chambers: - 20 pads in azimuth/sl - 40 pads parallel to beam/sl - 160 anode wires - 1600 cathode pads read out Anode Wires

  12. ++ The CLAS Detector Central Microstrip Detector silicon wafers readout silicon strips large angle - vertex reconstruction - high rate operation near target - tracking in full azimuth silicon strips forward angle 5cm 10cm readout pitch ~ 300mm

  13. p- e- p g g K+ High Q2, low t ep eK+S0(gL(pp-)) event Central Detector e-

  14. Forward Detector System Upgrades • Replace Region 1, Region 2, Region 3 drift chambers • => similar design as current DCs, factor 2 smaller cell sizes • Time-of-flight detector with improved timing resolution • Forward calorimeter => extend g/p0 separation to higher momenta • + instrument coil regions with calorimetry (PbWO4 crystals ) • New Cherenkov Detector with pion threshold ~ 5GeV • Microstrip detector (forward angle portion)

  15. LTCC HTCC EC/preshowerEC CLAS++ - Electron/pion separation e- and p- inclusive cross sections

  16. Optics: 8 small angle mirrors focus in same sector. 8 large angle mirrors focus to opposite sector. Split in azimuth to avoid obstruction due to beam pipe h>99.5% ++ The CLAS Detector Inner Cerenkov Detector Split Mirror system Winston cones, PMTs Radiator Gas CO2

  17. Coil Calorimeter in Torus coil region Torus coils Inner Calorimeter e.g. PbWO4 crystals Readout with APD or magnetic field insensitive PMTs.

  18. - reduce scintillator width to 5cm - add second scintillator layer => dT ~ 50-60psec Forward TOF Detector - Improved Time Resolution

  19. method has been tested Pre-shower Calorimeter Scintillator/lead sandwich, with wavelength shifting fiber readout, ~ 4 rad. length. 3.5cm Lead sheets 1mm thick Wavelength Shifting Fibers embedded in scintillator

  20. CLAS ++- Expected Performance Forward Detector Central Detector Angular coverage: Tracks (inbending) 8o - 37o 40o - 135o Tracks (outbending) 5o - 37o 40o - 135o Photons 3o - 37o 40o - 135o Track resolution: dp (GeV/c) 0.003p + 0.001p2 dpT=0.02pT dq (mr) 1 5 df (mr) 2 - 5 2 Photon detection: Energy range > 150 MeV > 60 MeV dE/E 0.09 (1 GeV) 0.06 (1 GeV) dq (mr) 3 (1 GeV) 15 (1 GeV) Neutron detection: heff 0.5 (p > 1.5 GeV/c) Particle id: e/p >>1000 ( < 5 GeV/c) >100 ( > 5 GeV/c) p/K (4s) < 3 GeV/c 0.6 GeV/c p/p (4s) < 5 GeV/c 1.3 GeV/c

  21. Physics processes measured concurrently - I All reactions require: Forward tracking, HTCC, Forward TOF, Central solenoid Target: H2 Beam: E = 11 GeV, Pe > 0.70 L = 1035cm-2s-1, 2000 hours Physics quantity Equipment Reaction Description ep epg ep epe+e- ep e(D,N*)g ep ep(r,w,f) ep eN(p0,h,p+) ep eN(p0,h,p+) ep e(p+,p0,h,K+)X ep eN(p0,p+) ep eN(h,p+p-,w) DVCS, DVMP, internal qq (twist-2), qGq (twist-3), spin dynamics, proton tomography GPDs, H, x=x central tracker, central TOF, pre-shower EC, inner EC, central EC GPDs, -x<x<x N* transition GPDs GPDs spin/flavor separation central tracker, central TOF, central EC hard meson production short distance dynamics GPDs @ high t e(x) twist-3 distribution function, twist-3 sum rule quark transverse momentum-dependent distributions (TMD) central tracker central TOF ND - REM, RSM high mass N*, pQCD approach to scaling central tracker, central TOF, central EC spectroscopy of high mass N*

  22. Quark distribution q(x) Cross section difference Cross section qq distribution Modeling of the G eneralized P arton D istributions

  23. Q2, xB, t ranges measured simultaneously. A(Q2,xB,t) Ds (Q2,xB,t) s (Q2,xB,t) DVCS/BH projected for CLAS++at 11 GeV 972 data points measured simultaneously + high t (not shown)

  24. CLAS++: Kinematics for ep epg (DVCS) E = 11 GeV Q2=2.5GeV2 Q2=5GeV2 central detector central detector forward detector forward detector

  25. sL sT Separated Cross Section for ep epro (p+p-) xB = 0.3-0.4 -t = 0.2-0.3GeV2 central detector forward detector central detector forward detector

  26. Axial Compton Formfactor and ND(1232) Transition g*p ppo g*p ppo(gg) W > 2 GeV also: E1+/M1+

  27. Target: D2 Beam: E = 11 GeV, Pe > 0.70 L = 1035cm-2s-1, 2000 hours Physics processes measured concurrently - II All reactions require: Forward tracking, HTCC, Forward TOF, Central solenoid Physics quantity Reaction Description Equipment S.F. of “free” neutron neutron resonances F2n(x,Q2) A1/2,A3/2 (Q2) eD epsX eD eps(p-p),D+p- central tracker central TOF central EC o o central tracker, central TOF, pre-shower EC, inner EC GPD H(x,x,t) DVCS, N*VCS eD eDg eD eps(D0,N*)g GN*(t) central tracker central TOF, pre-shower EC twist-3 distribution functions eD e(M,g)X e(x) eD e(n,p) ep ep+n neutron magnetic form factor GMn(Q2) central tracker central TOF eD eD(r,w,f) color transparency in coherent VM production central tracker central TOF ds(t1)/ds(t2) vs Q2 color transparency at fixed coherence length central tracker central TOF eD e(r,w,f)X sA/AsN

  28. ps n Structure of “Free” Neutrons - e.g. F2n e- e- Requires detection of a slow recoil proton at backward angles and with momenta ~60-150MeV/c Measure Q2 dependence simultaneously

  29. eD eDr0 Structure of bound Neutrons & Color Transparency Bound Neutron Color Transparency 500hrs

  30. CLAS++: Neutron GMn E = 11 GeV eD en(ps) ep ep+n

  31. H H, E H, E Physics processes measured concurrently - III Target: Polarized H/D Beam: E = 11 GeV, Pe > 0.70, Pp=0.75,PD=0.35 L = 1035cm-2s-1, 1000 hrs NH3, 1000 hrs ND3 All reactions require: Forward tracking, HTCC, Forward TOF Physics quantity Equipment Reaction Physics description A1p, g1p, g2p,G1p proton spin structure neutron spin structure e p eX, epT eX e D eX, eDT eX transverse target A1n, g1n, g2n, G1n ep epg DVCS/BH target SSA central tracker, central TOF, preshower EC GPDs H, E, e p epg DVCS/BH double asym. DVMP target SSA central tracker, central TOF preshower EC ep eN(p0,h,p+) GPDs e p eN(p0,h,p+) DVMP/BH double asym. preshower EC central tracker central TOF sinf ep e(p+,p0,h,K+)X Ddv/dv AUL quark flavor tagging eD e(p-,p0,h)X transverse target sinf AUT epT e(p+,p0,h,K+)X quark transversity du/u preshower EC

  32. “duality” “duality” g2p(x,Q2) at 11 GeV with transverse target 1000 hrs @ 1035cm-2s-1 /target Measure Q2 dependence simultaneously CLAS++: A1p(x,Q2) , g2p(x,Q2)A1d (x,Q2),A1n (x,Q2)

  33. duality Semi-Inclusive Deeply Inelastic Scattering Flavor separation ep ep+X ed ep- X ep ep+X twist-3 Quark transversity

  34. Physics processes measured concurrently - IV Target: Nuclear Beam: E = 11 GeV, Pe > 0.70 L = 1035cm-2s-1, 2000 hrs All reactions require: Forward tracking, HTCC, Forward TOF Physics quantity Equipment Reaction Physics description e2H e hadrons X space-time characteristics of hadronization (DIS kinematics) central tracker central TOF central EC, preshower EC Hadronization length vs. Q2, v, pT, z, hadron mass and size, and quark flavor; quark energy loss, gluon emission properties, quark-gluon correlations e14N e hadrons X e56Fe e hadrons X e84Kr e hadrons X e197Au e hadrons X hadrons =p0, p+, p-, h, w, h’, f, K+, K- ,K0, p, p, L, L(1520), S+, S0, S0, X0, X- color transparency in r production from complex nuclei e14N erX color transparency at fixed coherence length central tracker central TOF e56Fe erX

  35. Space-Time Characteristics of Nuclear Hadronisation

  36. Physics potentials with forward electron facility He - gas targets Meson spectroscopy, e.g. with 4 Heavy baryon spectroscopy, e.g X* Time-like virtual-Compton-scattering “g”p -> pe+e- Structure functions at very low Q2 J/y production others...

  37. Physics goals withCLAS++and Hall B The primary goal of experiments using the CLAS ++ detector at energies up to 12 GeV is the study of the internal nucleon dynamics in terms of elementary degrees of freedom, and the QCD structure of hadrons in the nuclear medium. Towards this end, the detector has been optimized for studies of exclusive and semi-inclusive reactions in a wide kinematic range. Inclusive processes, for which the unique properties of the Hall B instrumentation are essential (e.g. polarized NH3(ND3), neutron tagger, forward electron tagger), will be measured as well.

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