Эксперимент OLYMPUS

  • View
    64

  • Download
    0

Embed Size (px)

DESCRIPTION

OLYMPUS. , 24 .1 2 .200 9. . - OLYMPUS . - . - PowerPoint PPT Presentation

Transcript

  • OLYMPUS ,24.12.2009

  • - OLYMPUS

  • - , e-p - :M ~

  • GE/GM Rosenbluth separation(SLAC) (JLab Hall A) !

  • OLYMPUS DORIS (DESY, ), , >100mA ~3*1015 atoms/cm2 @ 100 mA L = 2x1033 cm-2s-1() BLAST MIT : e+-p e--p 2.0GeV [0.35 .. 0.90] Q2 ~2.2 (GeV/c)2
  • : 20o < q < 80o, -15o < < 15o Bmax = 3.8 kG , PID () , ToF, PID (p/p) BLAST ~1 ~1 Lumi

  • OLYMPUSMIT Arizona, Hampton, Colorado, Kentucky, New HampshireDESY (Bari, Ferrara, Rome, Bonn, Erlangen, Mainz, Glasgow) : .,., ., ., ., ., ., ., ., .

  • DESY PRC 2009 Technical Review DESY 2009US DoE 1.5

    Now! TDR MoU2010 BLAST DESY, DORIS, 2011 2012 2013-2014

  • Monte-Carlo ep-elastic Slow Control Online Monitoring softwareDetector alignment tracking software, ,

  • 2x 120 (GEM ):SC MWPCsUnified GEM/MWPC/SC tracker (redundancy) GEMtiming ( /)ep-elastic 2011 ?

  • Monte-Carlo BhaBha/Moeller , , PbF2 A4 (Univ. Mainz)Moeller(e-e- e-e-)BhaBha(e+e- e+e-)Annihilation(e+e- gg) GEANT4 Monte-Carlo :@25mrad, ~3m : kHz

  • 23 (+1 )XY- backplane 1 - 2.5 ~100x1002, frame LeCroy PCOS4 readout (INFN Rome):VME , ~15ms, multi-event fast cathode OR signal () ep-elastic ,

  • Slow Control Online Monitoring software HERMES (p,2p) - -

  • Summary OLYMPUS ,

  • BC-408 ~100x100x15mm2Hamamatsu 1 R4998 PMTs(p,2p) : + 623B LeCroy LEDs:
  • Survey, alignment & tracking software (survey + alignment with tracks) GEM trackingTracking ep-elastic Lumi beam line trackingBLAST OLYMPUSBLAST reconstruction display

  • (.)

    01-02/2010 03-??/2010 ??-10/2010 3- XY- (1 )11/2010 3- 09-12/2010 DAQ01-12/2010 LV, HV, cabling, Slow Control DESY12/2010 3- DESY 01-06/2011 () DESY01-06/2011, 3+1 07/2011 23 DESY 08-12/2011OLYMPUS commissioning01-12/2012

  • ()

    01-02/2010 01-03/2010 ( ?)04-10/2010 11/2010 09-12/2010 DAQ01-12/2010 HV, cabling, Slow Control DESY12/2010 DESY (1 )01-06/2011 () DESY07/2011 DESY 08-12/2011OLYMPUS commissioning01-12/2012

  • : Rosenbluth separation - : : Q2 e :

  • : : ( ) ( ) :

  • (2x9 ) GEM upgrade

  • 8 6730 A 3700 G 3D

  • e+-p e--p P.G. Blunden et al.,Phys. Rev. C 72, 034612 (2005)

  • OLYMPUS. Study of pGE/GM ratio in elastic ep-scattering at DORIS.

    Contribution from two photon exchange diagram not taken into account in traditional analysis may be an explanation:

  • S.Belostotski Seminar HEPD, April 09JLAB Polarization Transfer experiment (V.Punjabi, C.F.Perdrisat, et al. Phys.Rev. C71, 2005)dipoleHRSpprotonpolarimeterVertical bending B=45 deg.dipoleHRSeEMCPolarized e-beam Pe ~0.4-0.6,0.934-4.091 GeV, 5-15 A.

    JLAB Hall A two-arm spectrometer (top view)

  • Competition , e+-p e--p

    EbeamGeV-2 sec-1eminQ2 (GeV/c)2VEPP-31.6~ 10310.40.1 .. 1.82010 2012JLab5.7~ 1.3*10330.20.5 .. 2.12012 - ?OLYMPUS2.0~2.0*10330.40.6 .. 2.22012

  • JLab Approved experiment to compare e+p to e-p elastic scattering using secondary beams and the CEBAF Large Acceptance Spectrometer. Challenging systematics.

    NovosibirskSimilar experiment to DESY experiment has been considered. Positron currents are about an order of magnitude lower. No momentum measurement.

    Parity violating electron scattering Experiments at JLab and Mainz which measure transverse spin asymmetries are sensitive to two photon effects but not directly to the contribution which enters in GEp/GMp.

  • S.Belostotski Seminar HEPD, April 09VEPP-3 experimentEe=1.6 GeV (up to 2 GeV)electron current ~ 30mA, positron current limited to ~ 9mA HERMES type gas target 1015 atoms/cm2, L1031cm-2s

  • Sufficient counts at all angles only for E
  • Lowest epsilon ~0.4 only for E < 2.3 GeVAt epsilon = 0.4, require E>2 GeV to maintain Q2 > 2 (GeV/c)2 BLAST@DORIS (OLYMPUS): acceptance

  • Blunden et al.Prediction: proton form factor ratio

  • Rosenbluth separation, illustration

  • Speculation : there are radiative corrections to Rosenbluth experiments that are important and are not included missing correction : linear in e, not strongly Q2 dependentGE term is proportionally smaller at large Q2 effect more visible at large Q2Possible explanation of discrepancy

  • Copper layer-sandwiched kapton foil with chemically etched micro-hole pattern gas amplification in the hole GEM = Gas Electron Multiplier introduced by F. Sauli in mid 90s, F. Sauli et al., NIMA 386 (1997) 531Upgrade: GEM vertex detector

  • Forward trackers10o2 tGEM trackers, 30msr, 10o,R=160/230/300cm, dR=70cm, 3 tracking planes Upgrade: forward luminosity monitor0o, 1TPE effects 0

  • This slide shows a schematics of the BLAST detector. It is left-right symmetric and covers a large solid angle of 20-80 degrees and +-15 degrees oop. The in-plane sectors are instrumented with wire chambers, aerogel Cerenkov counters and thin plastic scintillators.The neutron counter array is asymmetric to enhance the sensitivity to Gen as will be clear in a minute.Here are a few pictures of the setup