1. 2/11/200521st Winter's Workshop at Brekenridge 1 PHENIX Muon Trigger Upgrade for the Study of Quark Contribution to Proton Spin Structure Wei Xie (Riken-BNL Research Center) for PHENIX Collaboration

2. 2/11/200521st Winter's Workshop at Brekenridge 2 Proton Spin Structure Naive parton model: valance quark are responsible for proton spin QCD: sea quark and gluons. Parton orbital angler momentum also contribute. Proton spin: ½ = ½  (quark)+  G(gluon) + L z Proton  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)

3. 2/11/200521st Winter's Workshop at Brekenridge 3 Current Measurement on Quark and Gluon spin SLAC: E80, E130, E142, E143, E154, E155 (1978-2001) CERN: EMC, SMC, COMPASS (1988-2004) DESY: HERMES (1995-2004) Quark spin : well constrained Sea Quark spin:large uncertainty Gluon spin:Unknown

4. 2/11/200521st Winter's Workshop at Brekenridge 4 Spin of Different Flavor of Quarks has been Measured Q 2 is low “Hadron taging” technique relies on knowledge of fragmentation functions Hermes: Phys.Rev.Lett 92 (2004) 012005

5. 2/11/200521st Winter's Workshop at Brekenridge 5 How PHENIX Measure Quark Spin W is produced through V-A process, helicity of quark is fixed:,When X a >>X b,When X b >>X a AW dx dx L b b () () ( )    Excellent ability to measure electron Excellent ability to measure muon

6. 2/11/200521st Winter's Workshop at Brekenridge 6 Expected PHENIX Measurement Annu. Rev. Nucl. Part. Sci.2000.50:525-75 a.u.

7. 2/11/200521st Winter's Workshop at Brekenridge 7 A trigger is needed to select only interesting events to record. W sample: ~10 4 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 Single Muon Trigger Need Upgrade

8. 2/11/200521st Winter's Workshop at Brekenridge 8 Hodoscope I Cerenkov Hodoscope II Ideas for trigger upgrade Pad Chamber II MuTr#1 Nosecone calorimeter Pad Chamber I MuID road MuTr#2 MuTr#3 PHENIX magnetic field

9. 2/11/200521st Winter's Workshop at Brekenridge 9 Muon road ID  (  )=angle I – angle II: momentum cut Option I: pad chamber solution Enough rejection power with good efficiency for high pT muons  deg <0.7<1.0<2.0 rejection360001998010090

10. 2/11/200521st Winter's Workshop at Brekenridge 10 -- ++ Sagitta<= 1 strip Sagitta< =2 strips Sagitta< =3 strips Rej23700109007180 Result from Kazuya Aoki A birds eye view Option II: MuTr Solution efficiency Sagitta<=1 strip Sagitta<=2 strips Sagitta<=3 strips Enough rejection power with good efficiency for high pT muons

11. 2/11/200521st Winter's Workshop at Brekenridge 11 Ongoing R&D Effort Measurement of background in central and forward region using scintilliator has been successfully done by RBRC and UIUC. Outgoing beam background (attenuated by PHENIX absorber ) Incoming beam background (un-attenuated) Neutron background which is out of time. 3 background components: Clock Forward Forward&BBCLL1 Forward&MUIDS_1D

12. 2/11/200521st Winter's Workshop at Brekenridge 12 Plan to use CMS RPC technology Picture of 2 chambers HV courtesy of Y. Mao Gas 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. Chamber technology: Good position and time resolution and cheap price

13. 2/11/200521st 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.

14. 2/11/200521st Winter's Workshop at Brekenridge 14 Possible Configuration 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) MuTr#1 Nosecone calorimeter MuTr#2 MuTr#3 MuID

15. 2/11/200521st Winter's Workshop at Brekenridge 15 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 FieldsRBRC Gerry Bunce, Wei Xie Abilene Christian University Rusty Towell, Larry Isenhower Peking University Yajun Mao, Ran Han, Hongxue Ye, Hongtao Liu Who is proposing?

16. 2/11/200521st Winter's Workshop at Brekenridge 16 backup

17. 2/11/200521st Winter's Workshop at Brekenridge 17 An Alternative Way to Measure Quark Spin Nadolsky and Yuan, Nucl. Phys.B 666(2003) 31). A L (W + ) A L (W +and W - ) p T (muon) Resummation Method: first principles calculation by Nadolsky and Yuan at NLO pQCD (Nucl. Phys.B 666(2003) 31). When there’s no charge sign identification

18. 2/11/200521st Winter's Workshop at Brekenridge 18 Study Spin Structure in Deep Inelastic Scattering Gluon included in NLO: Un-polarized : polarized: LO picture: S    S q  S q  J z = -1/2 proton S   S q  forbidden J z = -3/2 Experimental measurement:

19. 2/11/200521st 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.

20. 2/11/200521st Winter's Workshop at Brekenridge 20 Study Spin Structure in polarized p-p collision LO: Many different channel to measure  G, e.g. prompt photon production: Solid theoretical support:

21. 2/11/200521st Winter's Workshop at Brekenridge 21 Past DIS experiment