300 likes | 411 Views
PHENIX Charm Results in Au-Au, d-Au and p-p Collisions. Wei Xie (Riken-BNL Research Center) for PHENIX Collaboration. RHIC/AGS users meeting in 2004. PHENIX Heavy Flavor Physics: results and perspectives. W. Xie (UC. Riverside) PHENIX Collaboration.
E N D
PHENIX Charm Results in Au-Au, d-Au and p-p Collisions. Wei Xie (Riken-BNL Research Center) for PHENIX Collaboration RHIC/AGS users meeting in 2004
PHENIX Heavy Flavor Physics:results and perspectives W. Xie (UC. Riverside) PHENIX Collaboration Pioneering High Energy Nuclear Interaction eXperiment (460 participant from 57 institutions of 12 countries) • Maximal Set of Observables • Photons, Electrons, Muons, ID-hadrons • Highly Selective Triggering • High Rate Capability. • Rare Processes. QWG at Fermilab on Sep. 2003
l Charm measurements K+ e-/- e-/- e+/+ J/y K- • Sensitive to initial gluon density and gluon distribution e+/+ l D0 • Energy loss when propagating through dense medium • Different scaling properties in central and forward region indicate CGC. • Suppression or inhancement of charmonium in the madium is a critical signal for QGP.
PHENIX Ability Study Charm -- electron and muon measurenent • high resolution tracking and momentum measurement from Drift chamber. Good electron identification from Ring Imaging Cherenkov detector (RICH) and Electromagnetic Calorimeter (EMCal). • Good momentum resolution and muon identification from mID and mTrk. • Yield of Open Charm, Bottom from single leptons. • flow of charm. • J/y, y’ • Upsilon
cocktail -einvariant mass Methods of Open Charm Measurement • Subtraction of“photonic” sources. • conversion of photons from hadron decays in material • Dalitz decays of light mesons (p0, h, w, h, f) • Converter method • Comparison of e+/- spectra with and without converter allows separation of photonic and non-photonic sources of single electrons. • Direct measurement via -e coincidences • Yield of -e in vicinity of mass with mixed event subtraction & PHENIX measured correction
PHENIX: PRL 88(2002)192303 PHENIX PRELIMINARY NLO pQCD (M. Mangano et al., NPB405(1993)507) PYTHIA tuned to low energy data1 Data is excess of PYTHIA charm + bottom above pt=1.5 GeV/c PHENIX PYTHIA ISR +332 -281 cc=709b±85(stat) (sys) 1Phys. Rev. Lett. 88, 192303 (2002) PHENIX Non-Photonic Single Electron Spectra pp s = 200 GeV PHENIX data is consistent with the prediction of NLO pQCD calculation.
PHENIX PRELIMINARY PHENIX PRELIMINARY PHENIX PRELIMINARY 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAB 1/TAB 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAB 1/TAB PHENIX Non-Photonic Single Electron Spectra d-Au s = 200 GeV • Scale with number of collision in d-Au collision • Indication of zero shadowing effect at mid-rapidity or a balance of anti-shadowing with suppression due to final state interaction?
1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAA 1/TAA 1/TABEdN/dp3 [mb GeV-2] 1/TAA 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAA 1/TAA 1/TAA PHENIX Non-Photonic Single Electron Spectra Au-Au s = 200 GeV Deviation frpm p-p collision at large Pt • Scale with Ncoll in all the pheriphral bins • Deviation in large pt region in most central events. Statistical fluctuation or medium effect ?
130 GeV Au+Au (0-10%) D from PYTHIA D from Hydro 0.906 < < 1.042 B from PYTHIA B from Hydro Yellow band represents the set of alpha values consistent with the data at 90% Confidence Level dN/dy = A (Ncoll) e from PYTHIA e from Hydro Charm might thermalize and flow with others. The calculated electron spectrum is also consistent with the current electron data. (S. Batsouli, S.Kelly, M.Gyulassy, J.Nagle) Phys.Lett. B557 (2003) 26-32 Charm Energy Loss in the Medium Consistent with little energy loss due to “dead-cone” effect ?(D.E. Kharzeev et al.,Physics Letter B519(2001)199-206)
PHENIX PRELIMINARY Data indicate non-zero charm flow Charm v2: another way to look at the Energy loss Charm quark v2 is expected to be zero if there’s no energy loss PHENIX RUN2 data can not distinguish different scenario due to small statistics. PHENIX accumulated a factor of 20 more statistics in RUN4. Expected to have much more clear answer.
In Central region: Qs<m(cc) open charm production is expected to scale with Ncoll In forward region: Qs>m(cc). Open charm production is expected to scale with Npart(AA) and (pA) in forward rapidity region. Open Charm and CGC D.E. Kharzee, K. Tuchin, hep-ph0310358 Ongoing PHENIX open charm analysis on muon channel is expected to give the answer
J/y Measurement For Observation of QGP When Quark-Gluon plasma (QGP) is formed: Color screening will lead to suppression of charmonium production in heavy ion collisions(T. Matsui, H. Satz, Phys. Lett. B178(1986)416). More recent predictions of increased J/Y production at RHIC from recombination(R.L. Thews et al, Phys. Rev. C63(2001)054905) Raff Rapp’s theory ( add reference later) First Need to disentangle normal nuclear effect.
gluons in Pb / gluons in p Anti Shadowing Shadowing X What is the Normal Nuclear Effect There’re also suppression or enhancement due to normal nuclear effect: • Gluon(anti)shadowing • Nuclear absorption. • Initial status energy loss. • Cronin effect Eskola, et al., Nucl. Phys. A696 (2001) 729-746. Nuclear effect can be understood through p-p and p(d)-A collisions. PHENIX has measured J/Psi production in p-p, d-Au and AuAu Collisions
J/Psi rapidity Distribution In RUN3, we accumlated ~300nb-1 p-p and ~3nb-1 d-Au collisions.
Cronin Effect: pT broading Parton initial state multiple scattering leads to broading of J/Psi pt distributioin x2~ 0.003 x2~ 0.01 Broadening comparable to lower energy (s = 39 GeV in E866) x2~ 0.1
X2 (in gold) Initial Status Energy Loss • Energy loss expected to be weaker with increasing s (B. Kopeliovich et al., Nuclear Physics A696(2001)669-714) • Energy loss dominant at SPS • Shadowing start to be significant in at E866 energy • Energy loss negligible at RHIC
Gluon Shadowing and Nuclear Absorption Vogt, PRL 91:142301,2003 Kopeliovich, NP A696:669,2001 RdA RdA Low x2 ~ 0.003 (shadowing region) High x2 ~ 0.09 Low x2 ~ 0.003 Data favours weak shadowing and weak nuclear absorption effect. Steep rising of RdA with increasing Ncoll at large X2. Need more data to distinguish different models.
A modest baseline for the study of J/ψ in AuAu collisions has been obtained. • Enough or not dependent on the degree of suppression in AuAu collisions
J/y Measurement in Au-Au Collisions at snn=200GeV Result from 13 J/Psi signal Dy = 1.0 Coalescence model (Thews et al) Dy = 4.0 Stat. Model (Andronic et al.) Absorption model (Grandchamp et al.) Disfavor models with enhancement relative to binary collision scaling. Cannot discriminate between models that lead to suppression.
J/y Signal in RUN4 Au-Au Collisions RUN4 is a dedicated Au-Au run for J/Psi: PHENIX recorded ~300mb-1 Au-Au collisions. • Centrality 0 – 90% (from LVL2 filtered events) • NJ/y = 49.8 +- 11.3 • Mass Center = 3.12 +- 0.01 GeV • Mass Width = 32.2 +- 5.73 MeV • Expected to have 400J/Psi Expected to have 2x1600 J/Psi
PHENIX Proposal for Future Charm Measurement in Heavy-ion Collisions RUN5 : light nuclear collision at snn=200GeV to study the system size dependence of charm production. RUN6 : Au+Au at snn=62.4GeV to study the energy dependence of charm production. • RUN8:Au+Au atsnn=200GeV with Silicon Vertex Detector, which will enable PHENIX in the future runs : • to measure charm and beauty with pt above 4GeV/c • to quantify J/y suppression relative to open charm production • to improve mass resolution of J/y and g tobetter separate different state • to have robust measurement of gluon shadowing in the coming long d+Au collisions • …………………………………………………… • (Details see Gerd’s talk on Future of Charm Measurement in PHENIX this afternoon)
J/y Measurement in Au-Au Collisions at snn=200GeV Incl. systematic errors 90% C.L. One standard deviation Binary scaling Most probable value Expectation with absorption (4.4 and 7.1 mb) NA50 points normalized to pp point
Total Charm Cross Section s = pp 200 GeV PYTHIA comes out of retirement - Matches the line shape in the region that matters for the determination of the cross section, hence we use it to extrapolate over all phase space PHENIX PRELIMINARY PYTHIA charm + bottom line-shapes with independent floating normalizations that best fit the data Systematic error is determined by offsetting the data by the upper and lower systematic and extracting the cross section N
XF = Xd - XAu E866: PRL 84, 3256 (2000)NA3: ZP C20, 101 (1983) Comparision with lower s • Energy loss expected to be weaker with increasing s (B. Kopeliovich et al., Nuclear Physics A696(2001)669-714) • Energy loss dominant at SPS • Shadowing start to be significant in at E866 energy • Energy loss negligible at RHIC X2 (in gold)
J/Psi pT distributions J/ +- J/ +-
BBC South BBC North Spectator nucleons Au d d and Au participant nucleons Centrality analysis Au breaks up in our south beam counter • Define 4 centrality classes • Relate centrality to <Ncoll> through Glauber computation • <Ncoll> = 8.4 ± 0.7 <Ncoll> = 3.2 ± 0.3 Counts Peripheral <Ncoll> = 15.0 ± 1.0 Central MB South BBC Charge
Comparison With PYTHIA PHENIX PRELIMINARY PYTHIA charm + bottom under predict the tail by a factor of ~2-3 PHENIX PRELIMINARY PYTHIA charm alone under predicts the data by a factor of 2-5 at moderated pt
Short history of RHIC [1] nucl-ex/0305030 [2] hep-ex/0307019