PHENIX Muon Trigger Upgrade for the Study of Quark Contribution to Proton Spin Structure

1. PHENIX Muon Trigger Upgrade for the Study of Quark Contribution to Proton Spin Structure Wei Xie (Riken-BNL Research Center) for PHENIX Collaboration 21st Winter's Workshop at Brekenridge

2. Proton Proton Spin Structure Naive parton model: valance quark are responsible for proton spin f(x) = f(x) – f(x), where f(x) and f(x) are PDF with spin parallel and anti-parallel to the proton spin. (EMC: Spin crisis) QCD: sea quark and gluons. Parton orbital angler momentum also contribute . • Proton spin: • ½ = ½ (quark)+ G(gluon) + Lz 21st Winter's Workshop at Brekenridge

3. Current Measurement on Quark and Gluon spin Quark spin : well constrained Sea Quark spin: large uncertainty Gluon spin: Unknown • SLAC: E80, E130, E142, E143, E154, E155 (1978-2001) • CERN: EMC, SMC, COMPASS (1988-2004) • DESY: HERMES (1995-2004) 21st Winter's Workshop at Brekenridge

4. Hermes: Phys.Rev.Lett 92 (2004) 012005 Spin of Different Flavor of Quarks has been Measured • Q2 is low • “Hadron taging” technique relies on knowledge of fragmentation functions 21st Winter's Workshop at Brekenridge

5. Excellent ability to measure electron Excellent ability to measure muon ,When Xa>>Xb D d ( x ) ,When Xb>>Xa + = b A ( W ) L ) d ( x b How PHENIX Measure Quark Spin W is produced through V-A process, helicity of quark is fixed: 21st Winter's Workshop at Brekenridge

6. Expected PHENIX Measurement a.u. Annu. Rev. Nucl. Part. Sci.2000.50:525-75 21st Winter's Workshop at Brekenridge

7. Single Muon Trigger Need Upgrade • A trigger is needed to select only interesting events to record. • W sample: ~104 for the 800pb-1 luminosity. • can’t be pre-scaled! • collision rates in 500GeV run: ~12MHz,. • trigger rate w/ perfect background shielding: ~24KHz • trigger rate w/o background shielding~50KHz • PHENIX bandwidth: 12KHz(or 24KHz with additional $2M) • 1-2kHz assigned to W trigger • need additional rejection of 20-50, i.e. above 10000 rejection faactor 21st Winter's Workshop at Brekenridge

8. Pad Chamber II Ideas for trigger upgrade MuTr#3 MuTr#2 MuTr#1 MuID road Pad Chamber I Nosecone calorimeter Hodoscope I PHENIX magnetic field Hodoscope II Cerenkov 21st Winter's Workshop at Brekenridge

9. Option I: pad chamber solution Muon road ID ()=angle I – angle II: momentum cut Enough rejection power with good efficiency for high pT muons 21st Winter's Workshop at Brekenridge

10. Sagitta<=1 strip Sagitta<=2 strips Sagitta<=3 strips efficiency Option II: MuTr Solution m+ m- A birds eye view Result from Kazuya Aoki Enough rejection power with good efficiency for high pT muons 21st Winter's Workshop at Brekenridge

11. Clock Forward Forward&BBCLL1 Forward&MUIDS_1D Ongoing R&D Effort • Measurement of background in central and forward region using scintilliator has been successfully done by RBRC and UIUC. 3 background components: • Incoming beam background (un-attenuated) • Outgoing beam background (attenuated by PHENIX absorber) • Neutron background which is out of time. 21st Winter's Workshop at Brekenridge

12. HV Gas courtesy of Y. Mao Picture of 2 chambers Chamber technology:Good position and time resolution and cheap price • Plan to use CMS RPC technology • RPC test bench was setup at UIUC. • RPC prototype test during RUN5 p-p run by UIUC, RBRC and PKU • A byproduct: Relative-luminosity monitor. 21st Winter's Workshop at Brekenridge

13. R&D on fast readout FEE is ongoing at Kyoto University. • have built a test MuTr#1 chamber with the help of UMN • plan to have the final design in 2005 and mass production in 2006. MuTr test chamber at Kyoto. 21st Winter's Workshop at Brekenridge

14. Possible Configuration MuID MuTr#3 MuTr#2 MuTr#1 Nosecone calorimeter • pad chamber solution only • Downstream hybrid trigger • rebuilt MuTr electronics i.e. MuTr LL1 • combination of the two method • nosecone calorimeter (Vasily’s NCC talk) 21st Winter's Workshop at Brekenridge

15. Who is proposing? University of Colorado Frank Ellinghaus, Ed Kinney, Jamie Nagle, Joseph Seele, Matt Wysocki University of California at Riverside Ken Barish, Stefan Bathe, Tim Hester, Xinhua Li, Astrid Morreale, Richard Seto, Alexander Solin University of Illinois at Urbana Champaign Mickey Chiu, Matthias Grosse Perdekamp, Hiro Hiejima, Alexander Linden-Levy, Cody McCain, Jen-Chieh Peng, Joshua Rubin, Ralf Seidel Iowa State University John Lajoie, John Hill, Gary Sleege Kyoto University Kazuya Aoki, Ken-ichi Imai, Naohito Saito, Kohei Shoji Columbia University Cheng Yi Chi, William Zajc University of New Mexico Doug Fields RBRC Gerry Bunce, Wei Xie Abilene Christian University Rusty Towell, Larry Isenhower Peking University Yajun Mao, Ran Han, Hongxue Ye, Hongtao Liu 21st Winter's Workshop at Brekenridge

16. backup 21st Winter's Workshop at Brekenridge

17. Nadolsky and Yuan, Nucl. Phys.B 666(2003) 31). An Alternative Way to Measure Quark Spin Resummation Method: first principles calculation by Nadolsky and Yuan at NLO pQCD (Nucl. Phys.B 666(2003) 31). AL(W+) pT(muon) AL(W+and W-) When there’s no charge sign identification pT(muon) 21st Winter's Workshop at Brekenridge

18. proton Sq=1/2 Sq=-1/2 Sg=-1 Un-polarized: Jz = -1/2 Sq=-1/2 Sg=-1 polarized: forbidden Jz = -3/2 Gluon included in NLO: Study Spin Structure in Deep Inelastic Scattering LO picture: Experimental measurement: 21st Winter's Workshop at Brekenridge

19. Current DIS experiment for G measurement through hadron pair production Contributions to the asymmetry measurement Relative low Q^2 and need long running time. 21st Winter's Workshop at Brekenridge

20. LO: Study Spin Structure in polarized p-p collision Many different channel to measure G, e.g. prompt photon production: Solid theoretical support: 21st Winter's Workshop at Brekenridge

21. Past DIS experiment 21st Winter's Workshop at Brekenridge