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NCC for spin Physics for discussion and feedback

NCC for spin Physics for discussion and feedback. richard seto (a novice) Jan 11, 2006 Spin PWG. Spin Δ G direct photon direct photon jet to get x 2 Assume lowest order diagram high pt pi0, eta Δ Q - W isolation Transversity (??!) pA folks Colored Glass direct photon

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NCC for spin Physics for discussion and feedback

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  1. NCCfor spin Physicsfor discussion and feedback richard seto (a novice) Jan 11, 2006 Spin PWG

  2. Spin ΔG direct photon direct photon jet to get x2 Assume lowest order diagram high pt pi0, eta ΔQ - W isolation Transversity (??!) pA folks Colored Glass direct photon direct photon jet intrinsic kT etc Hard-photon parton energy loss direct photon direct photon- high pt particle (jet) high pt, high pt particles – large rapidity AuAu, pA (pi0, eta etc) Light/Heavy χC J/ψ+γ (J/ψ in muon arms) other states χB What Physics?

  3. NCC • EM calorimeter • covering full azimuth • 1<|y|<3 • Increases coverage of EM calorimetry by more than x10 • PHENIX • in early days • small coverage – very good instrumentation • future • LARGE coverage – very good instrumentation • +RHIC II+PHENIX DAQ+Trigger – good rate

  4. The Calorimeter • Tungsten w/ Silicon pad readout • 3 longitudinal readouts • pads 1.5 x 1.5 cm • 2 layers of fine pitch strips to identify π0s (gamma/pi0 or PS+SM) • EM res 30%/E

  5. Performance – pi0’s The idea • Two sets of strip detectors at ~? and ? X0 • first measures 1 or 2 showers • second measured asymmetry: do a fit • NCC measures total energy • can do a 3 C fit to the mass

  6. pi0 events x vs y for compartment 1 y-view pi0 clear in both views in pads and strips x-view compartment 1 1 2 gamma pi0 compartment 2 3 compartment 3

  7. pi0 clear in gamma/pi0 both views pi0 not clear in pads in x view

  8. Performance • Here we are not trying to measure the pi0 mass but • see if it’s a single photon or not • see if two photons are consistent with pi0 • Can measure pi0 spectrum “mass” (GeV) Eπ(GeV)

  9. Prototype in Test Beam Protvino

  10. 10 GeV electron σ~10% Pedestal and MIP

  11. schedule • report to DC Friday • end of Feb: BNL review – CDR due • CDR rough draft at • then to the DOE • Install • 1 side ~ 2009 • 2 sides ~2010

  12. rate assumptions RHIC II • Luminosity (ala Tony) • 200 GeV pp • L=1x1032 *12 weeks * 0.6(uptime) =238/pb • 500 GeV pp • L=5x1032 *12 weeks * 0.6(uptime) =1195/pb • heavy ions • 200 GeV AuAu • L=7x1027 *12 weeks * 0.6(uptime) =0.018/pb • 200 GeV CuCu • L=8x1028 *12 weeks * 0.6(uptime) =0.180/pb • 200 GeV pA • L=2.5x1029 *12 weeks * 0.6(uptime) =0.5976/pb • use this for 250x100 additional penalty of eff=0.25 (vertex cut, recon eff etc)

  13. 250x250 100x100 log Q2 log Q2 Direct photon Coverage in log x and log Q2 red-NCC blue – EMC 10-3 <X< 0.8 Assume pT~5 GeV z scale is linear z scale is linear log x2 log x2 Events RHIC II log Q2 z scale is log log Q2 log x2 log x2

  14. 500 GeV pp Events RHIC II log Qsq log(x2)

  15. 200 GeV pp

  16. 500 GeV pp all other sources direct photons 1<η<1.5 1.5<η<2 2<η<2.5 2.5<η<3 • direct photon/pi0=1 pT~ 20 • need to suppress background

  17. 500 GeV ppisolation cone energy cutR=Δη2+ Δφ2 Econe Econe/Egamma <0.1 is this infared safe? Try R=0.25, 0.5, 0.8, 1.2 E in isolation cone R=0.25 black 0.5 green 0.8 red 1.2 blue direct photon/other photon Econe/Egamma cut get 1/1 ratio at pt~8 GeV need another factor of 3-4 to get to pt=5

  18. direct photon/pi0=1 pT~ 20 isolation cut direct photon/other =1 for pT~8 GeV gamma/pi0 detector get another suppression factor of 3-4 pT~5 Gev 500 GeV ppisolation cut after isolation cut R=0.8 Econe/Egamma <0.1 No isolation cut

  19. 200 GeV pp

  20. Jet angle resolution from Vasilyi.e. 8 degrees

  21. Resolution of log(x2)=[log(x2)-log(xmesured)]/log(x2) example – 500 GeV sample resolutions in log x2

  22. 100x100 250x100 250x250 x-error bar: resolution in x y-error bar: sqrt(Nevets) assume runs for RHIC II from Tony for pp

  23. ΔθJet=0º ΔθJet=8º ΔθJet=16º for 100x100 use different jet resolutions (0,8,16,30,45) ΔθJet=30º ΔθJet=45º

  24. ΔθJet=0º ΔθJet=8º ΔθJet=16º for 250x250 use different jet resolutions (0,8,16,30,45) ΔθJet=30º ΔθJet=45º

  25. How well can we measure ΔG • Next steps (Ken Barish using Yuji’s code) • Assume polarization ~0.7 • in each event weight by spin dependent structure function/ordinary structure function • additional weight by cross section*Lum/Nthrown • save N++ and N+- • At the end of the run • give errors according to N • Form ALL= vs xmeasured

  26. Getting to ΔG • where • a (from pythia) • F1 from PDF used in pythia • g1 from GS or AAC • G from GS or AAC are “known” A1p

  27. If we do this Are we ready? • What else should we do? • For direct photons • Transverse spin physics • Other ΔG • Can we get some help?

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