Presentation on theme: "STAR Heavy Flavor Measurements in Heavy- ion Collisions 1 Outline : Quarkonia Measurements in p+p, d+Au and Au+Au collisions Open Charm Measurement."— Presentation transcript:
STAR Heavy Flavor Measurements in Heavy- ion Collisions 1 Outline : Quarkonia Measurements in p+p, d+Au and Au+Au collisions Open Charm Measurement D meson direct reconstruction. Non-photonic electron Summary of the Present Results. Future STAR Heavy Flavor Program. 06/18/2012UIC HF Workshop 2012 W. Xie for STAR Collaboration (PURDUE University, West Lafayette)
Quarkonia Suppression: “Smoking Gun” for QGP 3 cc J/ D+D+ d Low temperature Vacuum High temperature High density (screening effect take place) Sequential melting a QGP thermometer H. Satz, NPA 783 (2007) 249c. d D-D-
The life of Quarkonia in the Medium can be Complicated 4 Observed J/ is a mixture of direct production+feeddown ( R. Vogt: Phys. Rep. 310, 197 (1999)). – All J/ ~ 0.6J/ (Direct) + ~0.3 c + ~0.1 ’ –B meson feed down. Important to disentangle different component Suppression and enhancement in the “cold” nuclear medium – Nuclear Absorption, Gluon shadowing, initial state energy loss, Cronin effect and gluon saturation (CGC) Hot/dense medium effect – J/ dissociation, i.e. suppression – Recombination from uncorrelated charm pairs D+D+ cc c J/
Important to Study Open Heavy Flavor Production A good reference to J/Ψ suppression or enhancement. – Same or similar initial state effect. CGC, Shadowing, initial state energy loss, etc. – Large cross section (compared to J/ψ). Probability for recombination. Accurate reference measurements. One of the important probes complimentary to J/ψ measurements – Interactions between heavy quark and medium are quite different from the ones for light quarks gluon radiation, collisional energy loss, collisional disassociation, etc – allow further understanding of the medium properties. 5
6 The STAR Detector 6 MRPC ToF barrel BBC PMD FPD FMSFMS EMC barrel EMC End Cap DAQ1000 Completed TPC FTPC FGT Ongoing R&D FHC HLT HFT MTD
Signals Observed in STAR 7 STAR can measure heavy flavor of all different kind (J/ψ, D0, D*, electron …) in broad pT range. at both mid and forward rapidity in all collision species. forward J/ψ D 0 Au+Au 200 GeV D* p+p 200 GeV D* p+p 500 GeV
STAR Charmonia Measurements 8 e-/-e-/- e+/+e+/+
J/ Suppression/Enhancement in 200GeV d+A and A+A and Collisions d+Au Collisions: Nice consistency with PHENIX Cu+Cu Collisions: R AA (p >5 GeV/c) = 1.4± 0.4±0.2 R AA seems larger at higher pT. Model favored by data: 2-component: nucl-th/0806.1239 Incl. color screening, hadron phase dissociation, coalescence, B feeddown. Model unfavored by the data: AdS/CFT+Hydro: JPG35,104137(2008) 9 Phys.Rev.C80:041902,2009
R AA vs. p T vs. Npart 10 Consistent with unity at high p T in (semi-) peripheral collisions Systematically higher at high p T in all centralities Suppression in central collisions at high p T System size dependence due to J/ formation time effect? Escaping at high p T ? See Hao Qiu’s talk this afternoon for details
11 J/ flow: more discriminating power If charm quark flows. J/Psi from recombination also flow. If the observation is consistent with zero flow, it could mean J/psi does not flow OR Flow is small due to mass ordering effect OR Recombination is not a dominant process. Yan,Zhuang,Xu PRL 97, 232301 (2006) J/ PHENIX NPE v2: arXiv:1005.1627v2 x y z
J/ spectra in 200GeV Au+Au collisions 12 Broad pT coverage from 0 to 10 GeV/c J/ spectra significantly softer than the prediction from light hadrons Much smaller radial flow because it’s too heavy? Regeneration at low p T ? Phys. Rev. Lett. 98, 232301 (2007) See Hao Qiu’s talk this afternoon for details
STAR Preliminary J/ elliptic flow v 2 13 disfavors the case that J/Ψ with pT > 2GeV/c is produced dominantly by coalescence from thermalized charm and anti-charm quarks. See Hao Qiu’s talk this afternoon for details
STAR Preliminary The sQGP is Complicated 14 We thus need more probes, other than charms, to have a more complete picture of its properties, e.g. Upslions. Cleaner Probes compared to J/psi: recombination can be neglected at RHIC Grandchamp, Sun, Van Hess, Rapp, PRC 73, 064906 (2006) Final state co-mover absorption is small. See A. Kesich’s talk for details
A Quick Glimpse of STAR Upsilon Measurements 15 Consistent with the melting of all excited states. Models from M. Strickland and D. Bazow, arXiv:1112.2761v4 See A. Kesich’s talk for details
STAR Open Charm Measurements 16 D0D0 K+K+ l K-K- e-/-e-/- D0D0
17 D 0 and D* p T spectra in p+p 200 GeV  C. Amsler et al. (PDG), PLB 667 (2008) 1.  FONLL: M. Cacciari, PRL 95 (2005) 122001. arXiv:1204.4244. D 0 scaled by N cc / N D0 = 1 / 0.56  D* scaled by N cc / N D* = 1 / 0.22  Consistent with FONLL  upper limit. Xsec = dN/dy| cc y=0 × F × pp F = 4.7 ± 0.7 scale to full rapidity. pp (NSD) = 30 mb
18 D 0 signal in Au+Au 200 GeV Year 2010 minimum bias 0-80% 280M Au+Au 200 GeV events. 8- signal observed. Mass = 1863 ± 2 MeV (PDG value is 1864.5 ± 0.4 MeV) Width = 12 ± 2 MeV YiFei Zhang, JPG 38, 124142 (2011)
19 Charm cross section vs N bin Charm cross section follows number of binary collisions scaling => Charm quarks are mostly produced via initial hard scatterings. All of the measurements are consistent. Year 2003 d+Au : D 0 + e Year 2009 p+p : D 0 + D* Year 2010 Au+Au: D 0 Assuming N D0 / N cc = 0.56 does not change. Charm cross section in Au+Au 200 GeV: Mid-rapidity: 186 ± 22 (stat.) ± 30 (sys.) ± 18 (norm.) b Total cross section: 876 ± 103 (stat.) ± 211 (sys.) b  STAR d+Au: J. Adams, et al., PRL 94 (2005) 62301  FONLL: M. Cacciari, PRL 95 (2005) 122001.  NLO: R. Vogt, Eur.Phys.J.ST 155 (2008) 213  PHENIX e: A. Adare, et al., PRL 97 (2006) 252002. YiFei Zhang, JPG 38, 124142 (2011) arXiv:1204.4244.
20 D 0 R AA compared with Alice result YiFei Zhang, JPG 38, 124142 (2011) ALICE results shows D meson is suppressed at high pT. More luminosity and detector upgrade are needed from STAR to reach high pT. At present, NPE is the key to study high pT charm and bottom production. A. Rossi, JPG 38, 124139 (2011)
Non-photonic Electron Measurements DGLV: Djordjevic, PLB632, 81 (2006) BDMPS: Armesto, et al.,PLB637, 362 (2006) T-Matrix: Van Hees et al., PRL100,192301(2008). Coll. Dissoc. R. Sharma et al., PRC 80, 054902(2009). Ads/CFT: W. Horowitz Ph.D thesis. RL.+ Coll. J. Aichelin et al., SQM11 21 See M. Mustafa talk in the afternoon. STAR: PRL 106, 159902 (2011) PHENIX: arXiv:1005.1627v2
Summary for the STAR Measurements 22 No suppression for J/psi at high p T (5-10 GeV/c) in 200GeV Cu+Cu and peripheral Au+Au collisions, suppression at high p T in central Au+Au collisions J/psi suppression at high p T less than that at low p T J/psi v 2 measurements are consistent with zero, disfavor production at pT > 2 GeV/c dominated by coalescence from thermalized charm quarks Upsilon measurement are consistent with 2S and 3S state melting.
23 The charm cross section per nucleon-nucleon 200 GeV collision at mid-rapidity Charm cross sections at mid-rapidity follow number of binary collisions scaling, which indicates charm quarks are mostly produced via initial hard scatterings. D 0 nuclear modification factor R AA is measured. No obvious suppression observed at p T < 3 GeV/c. Large suppression of high-pT non-photonic electron production is observed. A real challenge to our understanding of energy loss mechanism. Summary for the STAR Measurements
24 Future of Heavy Flavor Measurement at STAR MTD (MRPC) See details in Yifei Zhang’s talk next
26 D 0 signal in p+p 200 GeV B.R. = 3.89% p+p minimum bias 105 M 4- signal observed. Different methods reproduce combinatorial background. Consistent results from two background methods. arXiv:1204.4244.
27 D* signal in p+p 200 GeV Minimum bias 105M events in p+p 200 GeV collisions. Two methods to reconstruct combinatorial background: wrong sign and side band. 8- signal observed. arXiv:1204.4244.