Heavy Flavor Results from STAR

Transcription

1 Heavy Flavor Results from STAR Wei Xie for STAR Collaboration (PURDUE University, West Lafayette) Open Heavy Flavor Production D meson direct measurement Non-photonic electron Heavy Quarkonia Production J/ψ Upsilon Heavy Flavor v 2 Summary and future perspective 11/19/2013 EMMI2013@LBNL 1

2 STAR HF Measurements* vs. Energy Coll. Spec. S NN (GeV) p+p d+au Au+Au U+U J/ψ L ~ 60µb -1 J/ψ, NPE L ~ 200µb -1 D0 L ~ 40µb -1 D0/D*, NPE, J/ψ, Upslion L ~ 30nb pb -1 J/ψ, Upsilon, NPE L ~ 10-30nb - 1 * Published or preliminary results since Reference data missing in low energies. Rely on model predictions. D0, NPE, J/ψ, Upslion L~ nb -1 2

3 Open Heavy Flavor Production D 0 K + e - / - l K - Non-photonic electron D 0 + 3

4 D 0 Signal in Au+Au 200 GeV Combining data from Run2010 & Total: ~800 M Min.Bias events Significant signals are observed In collisions of all centralities 4

5 D 0 Spectra in Au+Au 200 GeV He,Fries,Rapp: PRC86,014903; arxiv: ; private comm. Suppression at high p T in central and mid-central collisions Enhancement at intermediate p T. D0 freeze out earlier than light hadron and/or D0 does not have much radial flow as light quarks 5

6 Charm cross section vs N coll in Au+Au 200 GeV Run2003 d+au : D 0 + e Run2009 p+p : D 0 + D* Run 2010 & 2011 Au+Au: D 0 Assuming N D0 / N cc = 0.56 does not change for total cross sections. The charm cross section at mid-rapidity: dσ dy dσ cc (p + p) = 170 ± 45 (stat. ) sys. μ y=0 The charm total cross section : b (AuAu) = dy y=0 cc 175 ± 13 stat. ± 23 (sys) μb [1] STAR d+au: J. Adams, et al., PRL 94 (2005) [2] FONLL: M. Cacciari, PRL 95 (2005) [3] NLO: R. Vogt, Eur.Phys.J.ST 155 (2008) 213 [4] PHENIX e: A. Adare, et al., PRL 97 (2006) σ cc (p + p) = 797 ± 210 stat. 295 (sys) μb σ cc AuAu = 822 ± 62 stat. ± 192 μb Charm quarks are mostly produced via initial hard scatterings. Quantify other sources of production via high luminosity and upgrade. 6

7 Non-photonic Electron Spectra in Au+Au 200 GeV ~1 nb -1 sampled luminosity in Run2010 Au+Au collisions. ~6 pb -1 sampled luminosity in Run2005 and Run2008 p+p collisions. 7

8 Non-photonic Electron R AA in Au+Au 200 GeV Strong suppression at high p T in central collisions D0, NPE results seems to be consistent kinematics smearing & charm/bottom mixing Models with radiative energy loss alone underestimate the suppression Uncertainty dominated by p+p result. Compare with Au+Au spectra directly, if possible. DGLV: Djordjevic, PLB632, 81 (2006) CUJET: Buzzatti, arxiv: T-Matrix: Van Hees et al., PRL100,192301(2008). Coll. Dissoc. R. Sharma et al., PRC 80, (2009). Ads/CFT: W. Horowitz Ph.D thesis. 8

9 B suppression in Au+Au 200 GeV Based on NPE R AA at pt > 5 GeV/c and B fraction measurement. B significantly suppressed Agree with CMS observation via B->J/psi Based on NPE and D0 measurements Indicate suppression of B Large uncertainty. 9

10 Heavy Quarkonia Production e - / - e + / + 10

11 J/y Production in 200GeV p+p Collisions Color singlet model (NNLO*CS): P. Artoisenet et al., PRL. 101, (2008), and J.P. Lansberg private communication. Include no feeddown from higher mass state. LO CS+ color octet (CO): Y.-Q. Ma, K. Wang, and K.-T. Chao, Phys. Rev. D84, (2011), and private communication Agree with the data STAR: Phys. Rev. C80, (R) (2009) STAR: JPG 38, (2011) PHENIX: Phys. Rev. D 82, (2010) Color Evaporation Model: M. Bedjidian et al., hep-ph/ ; R. Vogt private communication Include feeddown from Xc and ψ Agree with the data 11

12 J/ψ spectra in 200GeV Au+Au collisions Broad p T coverage from 0 to 10 GeV/c J/ψ spectra significantly softer than light hadrons Much smaller radial flow? Regeneration at low p T? Tsallis Blast-Wave model: ZBT et al., arxiv: Yunpeng Liu et al.,, PLB 678:72 (2009) and private comminication Xingbo Zhao et al., PRC 82,064905(2010) and private communication Systematically higher at high p T in all centralities Suppression in central collisions at high p T formation time effect? Cronin effect? 12

13 Comparing with the Lower Energy Results Similar level of suppression from GeV at all centrality and at all pt Sequential melting? 13

14 v 2 Measurements from NPE, D0 and J/ψ Finite v 2 from charm quark coalescence? disfavors the case that J/Ψ with p T > 2GeV/c is produced dominantly by coalescence from thermalized charm and anti-charm quarks. 200 GeV Au+Au: Large NPE v 2 observed at low p T strong charm-medium interaction v 2 increase at p T > 3 GeV/c path length of energy loss Jet-like correlation. 39 and 62.4 GeV Au+Au: v 2 consistent with zero Might suggest charm medium interaction is not as strong as in 200 GeV 14

15 Comparison with LHC Results. Significantly less suppression at low pt at LHC. ~10x More Re-generation at LHC higher J/psi v2 at low pt 15

16 Upsilon: a Cleaner Probe Compared to J/ψ STAR Preliminary recombination can be neglected at RHIC Final state co-mover absorption is small. More suppression in more central collisions STAR Preliminary STAR Preliminary Consistent with prediction from a model requiring strong 2S and complete 3S suppression. Consistent with CMS results 16

17 Look at Open and Hidden Charm Together At RHIC, low pt J/psi is suppressed rel. to open charm High pt J/psi seems to follow the same suppression pattern as open charm High pt J/psi NOT suppressed relative to open charm? H. Satz, arxic: v2 17

18 Future of STAR Heavy Flavor Measurement MTD (MRPC) PIXEL: high hit resolution: 18.4µm X 18.4µm pitch Muon identification low thickness: 0.37% X Muon trigger 0 significantly enhance STAR capability on measuring heavy flavor production at RHIC, e.g. Direct reconstruction of D mesons at both low p T and high p T B J/ψ µµ +X, disentangle upsilon 1S/2S/3S. Study QGP thermal dilepton radiation Understanding background through e-muon correlation. See details in Xin Dong s Talk 18

19 Summary Observe large suppression of charm and bottom production through NPE and D 0 meson measurements in 200 GeV Au+Au collisions Observe larger NPE v 2 in 200 GeV than in 39 and 62.4 GeV Au+Au collisions, indicating the strength of charm-medium interaction increase with energy. J/ψ v 2 measurements disfavor the case that coalescence dominate the production at p T > 2 GeV/c. Observe Upsilon suppression, consistent with prediction from a model requiring strong 2S and complete 3S suppression STAR HFT and MTD upgrades together with existing subsystems and RHIC II luminosities will allow STAR to do prediction measurements. 19

20 Backup Slides 20

21 counts What are the corresponding pt (B meson) Red: pt(j/ ) > 6 GeV/c Blue: pt(e ± ) > 5GeV/c PYTHIA6 default setting pt (B meson: GeV/c) B meson significantly suppressed at 5-20 GeV/c at RHIC and LHC. 21

22 Large Heavy Flavor Elliptic Flow Observed 22

23 Large Heavy Flavor Elliptic Flow Observed 23

24 CNM Effects Observed at LHC R ppb (NPE) systematically above 1.0, consistent with PHENIX while R ppb (D) ~1.0. Coincidence due to systematics or B e? Consistent with the shadowing and CGC. 24

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26 Comparison with Models Current data placed some constraints on models Need PRECISION 26