MuTR upgrade at PHENIX for W boson measurement

1. MuTR upgrade at PHENIXfor W boson measurement MuTRG meeting @ Rikkyo Univ. 06/29/2009 Katsuro Nakamura

2. Why quark polarization proton • proton • spin 1/2 • uud (constituent quark model) • parton model • EMC measurement • all quarks (+ anti-quarks) in proton has only ~ 30% of proton spin •  spin pazzle • strange see-quark seem to have negative spin • see-quark polarization, gluon polarization momentum P parton momentum p (x: Bjorken x) Quark polarization, W boson measurement at PHENIX

3. quark polarization in proton • DIS (deep inelastic scattering) quark polarization measurement • DIS is sensitive only for charge or week charge • can’t separate flavor • Semi-inclusive DIS • including fragmentation function •  not direct measurement Global Fit (2008) Semi-inclusive DIS Quark polarization, W boson measurement at PHENIX

4. measurement of spin structure in proton with W bosron • W boson production in p-p collision • flavor combination is almost fixed • helicities of interacting partons are fixed • asymmetry A_L should be combination of 2 parton polarizations • In forward or backward region, single flavor polarization can be extracted Quark polarization, W boson measurement at PHENIX

5. Main PHENIX detector systemfor the W measurement • Drift Chamber • Pad Chamber • Time of Flight • PbSc, PbGl (EMCal) • Hadron Blind Detector Central Arm (electron measurement) e μ view • absorbers • Muon Tracking chamber (MuTR) • Muon Identifier (MuID) Muon Arm (muon measurement) view PHENIX detectors MuTR MuTR MuID MuID Quark polarization, W boson measurement at PHENIX

6. Expected count of electrons from W • measurement • reject hadron background with isolation cut • pick up high pT • Karatsu-san is studying cross section of W production in Central Arm Quark polarization, W boson measurement at PHENIX

7. expected W->lepton A_L W+e+ W-e- Quark polarization, W boson measurement at PHENIX

8. Expected count of muons from W • measurement • muons pT>20GeV/c is mainly from W decay W is dominant muons in Muon Arm (2000pb-1, with PYTHIA5.7) Quark polarization, W boson measurement at PHENIX

9. 300 pb-1 1300 pb-1 expected W->lepton A_L P = 0.70 1.2<|eta |<2.2 S/N = 3 momentum smeared result forward backward μ μ polarized p unpolarized p Quark polarization, W boson measurement at PHENIX

10. Challenge in PHENIX W->muon measurement recorded muon events (image) MuID rejection in 200GeV and 500GeV • σ(tot)=60mb, L=2x1032cm-2s-1 (500GeV) • collision rate = 12MHz • DAQ rate limit < 2Hz (for muon Arm) • Therefore, required rejection factor • > 6000 • But, MuID rejection factor (500GeV) • < 100 • We need another rejection power ! rejection (MuID&BBC/BBC(nvtx)) trigger momentum threshold 200 (MuID) 150 100 50 0 yielded muons 0 0.5 1.0 1.5 2.0 MHz BBC(nvtx) (estimated from ZDC narrow) = recorded muons recorded muons Quark polarization, W boson measurement at PHENIX

11. B PHENIX Muon Trigger Upgrade Project RPC MuID MuID RPC MuTR upgrade strategy select ⊿strip = small  select high pz track MuTR MuTR μ RPC absorber RPC (to be installed) provide timing information and rough position information (prototype was installed in run9) MuID trigger (existing) selecting muon event momentum thre. < 2GeV/c MuTR FEE upgrade (installing) fast selection of high-momentum-track

12. B Muon Tracker fast track selection (MuTRG) Local Level-1 trigger board (LL1 board) ADC ADC ADC Level-1 trigger Data Collecting Module (DCM) MuTRG-ADTX fast digitalized hit signal fast digitalized hit signal fast digitalized hit signal Quark polarization, W boson measurement at PHENIX Quark polarization, W boson measurement at PHENIX

13. MuTRG-ADTX • remote controllable threshold in discriminator • remote PROM, FPGA configuration • through optical line Quark polarization, W boson measurement at PHENIX

14. Electronics in MuTRG system Rack Room Interaction Region MuTRG-MRG MuTRG-DCMIF (many) MuTRG-ADTXs tracking chamber hit pattern x 344 (both Arms) x64 (both Arms) hit data hit data RPC trigger timing data + rough position data trigger module data collecting modules trigger Muon detector system FEE data from MuTR, MuID… MRG and DCMIF install plan and LL1 test plan

15. Numbers of electronics 1/16 of them installed (half of Oct5) All of them already installed MRG and DCMIF install plan and LL1 test plan

16. The effects of MuTRG-ADTX to MuTR installed plane installed plane • changes in all MuTR parameters (gain, RMS, hit timing) are all acceptable Oct.1 black: before install red: after install Oct.8 Gap.1 Pl.1 Gap.1 Pl.2 Gap.2 Pl.1 Gap.2 Pl.2 pedestal RMS value vs strip number (North, St.3) Quark polarization, W boson measurement at PHENIX

17. MuTRG system performance MuTRG efficiency vs MuTR charge • Important parameter for trigger system • efficiency • rejection factor • (MuTRG&MuID&BBC)/(MuID&BBC) plateau efficiency rate (Hz) Blue : MIP dist. Yellow : MIP x Eff. MuTR charge dist. Quark polarization, W boson measurement at PHENIX

18. RPC (Resistive Plate Chamber) μ • provide timing information • rough position resolution PHENIX RPC Detector Requirement RPC3 RPC1 RPC3 Quark polarization, W boson measurement at PHENIX

19. Fast result of RPC in Run9 prototype installed in Run9 • good timing resolution • clearly separate collision hit from beam BG μ from beam BG from collision St.3 St.2 beam BG time(St.2-St.3) Quark polarization, W boson measurement at PHENIX

20. MuTRG Milestones • 2008 autumn ~ winter • ADTX boards (North, 1/16 of South) were installed • 2009 Feb. • MRG, DCMIF boards were installed • 2009 Mar. ~ Jun. • Run-9 • 2009 Jun. 29 • This meeting * future plane • 2009 Jul. ~ Oct. • remaining ADTX, MRG, DCMIF boards to be installed • the end of 2009 • Run-10 will be started • mainly Au-Au (500GeV beam study run?) Quark polarization, W boson measurement at PHENIX

21. The End Quark polarization, W boson measurement at PHENIX

22. extraction of single flavor polarization forward backward xf(x) forward backward Quark polarization, W boson measurement at PHENIX

23. Cut Parameters Energy thre. = 0.5 GeV (for photon) Momentum thre. = 0.5 GeV (for charged particle) Cone size = 0.50 rad. (against leading particle) W events QCD events Cut function: y = 0.06x – 0.6