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DY at STAR for decadal plan (run15-20). Akio Ogawa. DY. DY : ~7 x 10 -5 mb @ 500GeV. Hadronic : ~30mb. 10 6. Hadron & photon backgrounds Charm & bottom backgrounds Need >100 Billion hadronic events to simulate backgrounds. PHENIX Muon Arm Eta = 1-2. DY Charm Bottom.
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DY at STARfor decadal plan (run15-20) Akio Ogawa
DY DY : ~7 x 10-5 mb @ 500GeV Hadronic : ~30mb 106 Hadron & photon backgrounds Charm & bottom backgrounds Need >100 Billion hadronic events to simulate backgrounds PHENIX Muon Arm Eta = 1-2 DY CharmBottom http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf
STAR forward detectors FTPC (to be removed next year) Proposed FHC (for jet & lambda) ≈ 6 Lint spaghetti calorimeter 10cm x 10cm x 120 cm “cells” DX shell R ~ 60cm FMS In open position x~50cm from beam No space for FHC near beam No space in front of FMS neither
DY signal pythia6.222, p+p @ sqrts=500 DY process, 4M events/6.7E-05mb ~ 60/pb e+/e- energy>10GeV & h>2 xF>0.1 (25GeV) 4GeV < invariant mass < 10GeV Everything h>2 14799 events FMS closed (FHC cannot be placed due To DX magnet) 6512 events FMS open (x=50cm) + FHC (x=60cm) 1436 events (1/5 from closed) Inv Mass E pT
(direct) b background pythia6.222, p+p @ sqrts=500 DY process, 4M events / 6.7E-05mb ~ 60/pb B production, 300M events / 5.2E-03mb ~ 58/pb (Fragmentation b need 180B events / 30mb ~ 60/pb) e+/e- energy>10GeV & h>2 xF>0.1 (25GeV) 4GeV < invariant mass < 10GeV FMS closed DY Direct B Direct B unlike Direct B like pT Inv Mass E FMS closed : small at high xF & high eta & mostly unlike sign
(direct) b background pythia6.222, p+p @ sqrts=500 DY process, 4M events / 6.7E-05mb ~ 60/pb B production, 300M events / 5.2E-03mb ~ 58/pb (Fragmentation b need 180B events / 30mb ~ 60/pb) e+/e- energy>10GeV & h>2 xF>0.1 (25GeV) 4GeV < invariant mass < 10GeV FMS open (x=50cm) + FHC (x=60cm) Everything h>2 FMS closed DY Direct B Electron/position radius from beam at FMS FMS closed : small at high xF & high eta & mostly unlike sign FMS opened + FHC : significant @ low xF & small eta (even smaller eta/phenix muon arm : b > DY)
High xF DY @ STAR needs • High h > 4 coverage • Additional e/Hadron separation • hadron suppression > 1/1000 per hadron • Additional e/Gamma separation (incl gamma->e+e-) • gamma suppression > 1/1000 per gamma • Forward tracking for charge like/unlike sign (?) • Significant trigger upgrades • FMS with localized hadron & neutral veto • Extension of west platform
DY @ STAR for decadal planrun15-20 • FFGT + Pre-Showers/Tracker/SMD + Shorter Ecal (PbW) + Hcal + removal of west platform 2) FFGT + Pre-showers/TRD/Tracker/SMD + FMS (fill 20cm x 20cm hole around beam pipe?) + extension of west platform
e/Hadron separation • Trigger & offline • FMS (rarely measure full hadron energy) • FMS + FHC veto (1/10 – 1/1000 depends on energy) No space for ecal + hcal at eta=4 between DX & poletip holder • Pb Converter + Early-shower detector(~1/10) • Electron-ID like TRD or TR-Tracker (1/10 – 1/100) • Offline • E(FMS)/p(tracking) Hard to measure p well at high xF with STAR magnet • FMS (or FMS-SMD) shower shape analysis (Need study)
H. Crawford/L. Bland • EM calorimeter… • 2500 PbWO crystals • APD readout • 1264 lead glass • PMT readout Existing west side of Wide Angle Hall wheel/spoke support for DX and hadron calorimeter • hadron calorimeter… • 1400 towers (Atlas) Concept for forward EM+hadron calorimeter at STAR DX Wide Angle Hall Floor HjC - STAR@BNL
Electron PID (hadron rejection) • Cherenkov • Beta(pion) @ 1GeV 0.99 • Beta(pion) @ 3GeV 0.999 • air 1/n 0.99970 • hydrogen 1/n 0.99986 • Beta(pion) @ 10GeV 0.9999 • Beta(pion) @ 30GeV 0.99999 • Beta(electron) @ 1GeV 0.9999999 • Transition Radiation Detector (TRD) • ALICE http://www-alice.gsi.de/trd/transp/andronic07.pdf • AMS http://cyclo.mit.edu/~bmonreal/trd.html • HERMES http://hermes.desy.de/notes/pub/96-LIB/thiessen.96.028.ps.gz
TRD • 1 layer (out of 20 layers) AMS TRD • http://cyclo.mit.edu/~bmonreal/trd.html • HERMES TRD Performance • http://hermes.desy.de/notes/pub/96-LIB/thiessen.96.028.ps.gz Electrons/positrons emit X-rays Which are detected in Xe/CO2 gas detector, in addition to normal ionization
e/Gamma separation • Trigger & offline • Neutral veto in Pre-Shower detector (~1/100) • Gamma->e+e- conversion in beam pipe • Pre-shower with 2MIP/e+e- conversion pair veto (~1/100?) • Gamma->e+e- conversion in preshower (~1/2) • Small radiation length in preshower (or 1st tracking station) desired • Thin Pre-Shower detector with good resolution to do 0mip - 1mip - 2mip separation • Offline • Reconstructing pi0 (and eta) and removing them in FMS ( ~ 1/10) • Tracking to resolve single electron to pair (? Need study)
GEM based Pre-shower & Early-shower detectors Red foils: H/V traces Blue foils: Diag traces Pre-shower 0.3mm – 0.9mm pitch 55k channels ~2RL Pb Converter Early-shower 2mm -3mm pitch 11k channel Total 66k channels Carl Gagliardi
Charge like/unlike sign • Charge like/unlike sign separation needed? • If so, STAR solenoid enough? • Or need forward dipole magnet? • Tracking • FGT with small R + a couple more rings ? • Another tracker at FMS (pre-shower or SMD) ? • Momentum resolution for E/p ? • c/b tag ?
STAR Magnetic Field Chris QM09 talk : http://drupal.star.bnl.gov/STAR/files/QM2009_Perkins_v5_0.ppt • Radial and Azimuthal fields impart impulses in the Φ direction and partially cancel
Run8 FMS-FTPC (Jim Drachenberg) ΔΦ = 0.1 Δz/pz (Δz=2.5m) = 0.25 radian / GeV For 10GeV at y=0 @ FMS Δy @ x=20cm = 0.5cm Δy @ x=40cm = 1.0cm Δy @ x=80cm = 2.0cm For 50GeV at y=0 @ FMS Δy @ x=20cm = 0.1cm Δy @ x=40cm = 0.2cm Δy @ x=80cm = 0.4cm FTPC+FMS have done charge separation with STAR magnet at 2.8<h<3.8 E ~ 10GeV http://www.star.bnl.gov/protected/spin/drach/Run8FMS/FMS-FTPC_correlation/
FGT extension? J. Balewski/MIT h = 2 h = 3 h = 4
H. Crawford/L. Bland Dipole Analysis Magnet Concept Present RHIC Interaction Regions Forward DY Interaction Region if charge sign required • Conceptual Plan to Allow DXA • reduce field strengths in D0,DX • move DX towards IP • DXA used for beams and for DY daughters HjC - STAR@BNL
DY @ STAR for decadal planrun15-20 • FFGT + Pre-Showers/Tracker/SMD + Shorter Ecal (PbW) + Hcal + removal of west platfrom ~ 10 M$ ?? 2) FFGT + Pre-showers/TRD/Tracker/SMD + FMS (fill 20cm x 20cm hole around beam pipe?) + extension of west platform ~ 5M$ ??
Some documents • Updated FHC proposal http://hena.lbl.gov/FMS/docs/hcal_proposal_update_091001.pdf • Hank's FHC talk at STAR upgrade meeting http://drupal.star.bnl.gov/STAR/system/files/FHC_091217.pdf • DY paper (2007) http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf
Attractive vs Repulsive Sivers Effects Unique Prediction of Gauge Theory ! Simple QED example: Drell-Yan: repulsive DIS: attractive Same inQCD: As a result:
DOE HP13 milestone “Test unique QCD predictions for relations between single-transverse spin phenomena in p+p scattering and those observed in deep-inelastic lepton scattering” with an estimated completion of 2015” HERMES Sivers Results RHIC II Drell Yan Projections 0 Sivers Amplitude Markus Diefenthaler DIS Workshop Műnchen, April 2007 0 0.1 0.2 0.3 x Attractive vs Repulsive Sivers Effects