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Open charm prospects for RUN5 pp

Open charm prospects for RUN5 pp. Kazuya Aoki Kyoto Univ. Muon Physics and Forward Upgrades Workshop Santa Fe, June 2004. Motivation for open charm (pp). Charm production is dominated by Gluon-gluon fusion Sensitive to gluon polarization Reference for J/ Y suppression or enhancement.

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Open charm prospects for RUN5 pp

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  1. Open charmprospects for RUN5 pp Kazuya Aoki Kyoto Univ. Muon Physics and Forward Upgrades Workshop Santa Fe, June 2004

  2. Motivation for open charm (pp) • Charm production is dominated by Gluon-gluon fusion • Sensitive to gluon polarization • Reference for J/Y suppression or enhancement

  3. Yield estimation in RUN5 Yield = s x L x BR x hacc • charm production Cross-section (s) • integrated luminosity in RUN5 (L) • Decay branch (BR) • PHENIX acceptance (hacc) • significance

  4. PHENIX sngl. electron sccbar709ub +/- 85 STAR sngl. electron sccbar1120ub +/- 200 +- 370 STAR D meson sccbar1300ub Theory sccbar ~130 ub Single electron spectraPHENIX VS STAR +332 -281 Ed3s /dp3[mbGeV-2c3] Hep-ex/0404032 STAR is slightly above PHENIX systematically Need to understand Systematically using Different channels!! Taken from Ralf Averbeck’s slide(QM2004)

  5. PHENIX trigger How to identify open charm STAR preliminary (d Au) MinBias • Direct measurements • D0  p+K- 60%ccbar (BR 3.8%) • D*+  p+(slow) D0 ~30% (BR 67.7% x 3.8%) MinBias p+K- MinBias /p0 trig • D*0  p0(slow) D0 ~30% (BR 61.9% x 3.8%) p+K- gg • D0  r+K- (BR 10%) p0 trig. p+p0 • Inclusive measurements • D0 m+ X (BR 6.5%) • D0  e+ X (BR 6.8%) m trig PHENIX (pp) and STAR preliminary (pp, dAu) e trig • Combination of above Charge conjugates of above , of course!

  6. PHENIXD0 pK search in central arm • RUN3 dAu case • Trial By Sasha Levedef and Hua Pei • Forget pid. Make combinations of all hadrons. • Identify K in high res. TOF. Treat other hadrons as pion So far negative results… • RUN3 pp case • I tried.

  7. PHENIX run3 ppD0pK search in central arm cuts h+ PT>0.5 , h- PT>0.5 D0 pT > 2GeV/c Same arm Exp 12 Obs 110 +- 70 There seems to be a peak The width is much narrower than I expected. Work in progress Run3 pp MinBias 1.7 nb-1 Anyway , How many D0 can we get in RUN5?

  8. Yield estimate with PYTHIA • ccbar X-section • PYTHIA 235ub (Ver. 6.1) • NLO pQCD 130 ub • PHENIX 709ub +/- 85 (syst.+332 / -281 ) • STAR 1120ub +/- 200 +/- 370 Scaling 709/235 ~3

  9. Integrated luminosity in RUN5MinBias Trigger • Only depends on the duration of RUN. • Trigger rate is fixed to 2kHz(bandwidth) x 10% • Duration 10 weeks x 50%(PHENIX eff.) • Integrated luminosity for MinBias rate x duration / sBBC= 6 x 108 / 21 mb = 28.6 nb-1 MinBias Ldt

  10. Maximum projection Minimum projection RUN4 achieved Integrated luminosity in RUN5 • Roser and Fischer projections Integrated luminosity [pb-1] delivered 30pb-1 8pb-1 4 14 [weeks in physics running] 10 weeks 7.5pb-1 2pb-1 collected minimum maximum Lcollected = Ldelivered x 50%(vtx cut) x 50%(PHENIX)

  11. Yield estimate with PYTHIAD0  pK P>0.4GeV/c to reach EMCal p Both particle in acc. PT>0.5GeV/c Decay corr. and efficiency x x ccbar D0 K 60% x 2 3.65% 235ub x 3 ~50% 0.5% x 82% Signal ~90% Signal ~ 10% Opposite arm Same arm p K p K

  12. Charge conjugates included. PYTHIA estimate ( pp ) pT>0.5 GeV/c for charged hadrons, pT>1 for p0 , pz>1GeV/c for m , pT>0.8GeV/c for e em efficiency to detect m in |h| acc. = ~70% When you use MuID only , you don’t need em

  13. Significance( S/sqrt(B) )for “same arm” case When you identify charge of m, m+ D0barp-K+ m- D0p+K- Signal estimate : PYTHIA BG estimate : RUN3 REAL DATA Make all combinations Of charged hadrons. Obviously these numbers are depend on cuts. Since I imposed rather loose cut, there’s room For optimization

  14. Summary • D0pK search in central arm • 2 major issues • Large background • displaced vertex cut reduces background dramatically  need silicon vertex tracker. • lack of trigger • m trigger enhances D0pK in central arm • Currently available solution of the 2 issues above. • I’d like to propose the prescale factor for single m trigger set to be as low as possible in RUN5 • m channel is unique to PHENIX

  15. Impact of displaced Vertex cut

  16. Trigger in RUN5 • Maximum case correspond to the red band. • Integrated lumi. • 3 pb-1/week x 10 weeks x 50% x 50% = 7.5 pb-1 • BBCLL1 at Lumi. Peak • 16 x103mb-1/s x 22mb = 352kHz (min scenario.. 100kHz) • BBCLL1 at Lumi. Average • 9 x 103mb-1/s x 22mb = 198kHz (min scenario.. 53kHz)

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