Heavy Flavor Physics at RHIC
Heavy Flavor Physics at RHIC
Matthias Grosse Perdekamp U of Illinois and RIKEN BNL
o Overview o Selected results from RHIC “light quark” jet quenching and elliptic flow
o Energy loss of heavy quarks in media as tool to study nuclear media formed in heavy ion collisions.
Heavy Flavor Physics at RHIC
Heavy Flavor Physics at RHIC: Overview
s)s,s, ΥJ/ψ c 321(, , open heavy flavor production spectroscopy:
QGP? A-A
Quarkonia as “Thermometer”: color screening depends on T
Matsui and Satz, Phy.Lett. B 178 (1986)416
1) Energy loss in dense and hot nuclear matter
2) Tomography of DHNM 3) Reference data for quarkonia
PDF(A) p/d-A
1) Modification of PDFs in nuclear environment (anti-) shadowing vs new state of matter (color glass condensate)
2) Reference data for initial state in A-A
QCD p-p, d-A, A-A
1) Cross sections vs rapidity and √s 2) Vacuum energy loss vs media
3) Reference data
1) Hadronization mechanism 2) Reference data for quarkonia
Polarized PDFs p-p
)( gxGmeasure formation process?
Heavy Flavor Physics at RHIC
Polarized pp: ΔG from charm production
Scale dependence reduced at NLO:Scale dependence reduced at NLO:
Double spin asymmetry electron asymmetry for charm production (I. Bojak and M. Stratmann, hep-ph/0112276)
T
eLL
x
A
Tx
LO NLO
Heavy Flavor Physics at RHIC
Relativistic Heavy Ion Collider
Au + Au collisions at 200 GeV/u p + p collisions up to 500 GeV spin polarized protons (70%) lots of combinations in species and energy
in between
Performance Au + Au p+p
snn 200 GeV 500 GeV
L [cm-2 s -1 ] 2 x 1026 2 x 1032
Cross-section 7 barns 60 mbarn Interaction rates 14 kHz 12 MHz
Design Parameters:
RHIC Capabilities
Heavy Flavor Physics at RHIC
Delivered 1196 (b)-1 to Phenix [week ago : 1060]
136 (b)-1 last week [best week: 158]
minimumprojection
physics target
maximumprojection
RHIC Running
2 x designLuminosity!
Heavy Flavor Physics at RHIC
Charm and J/ψ Data from RHIC
Run I, 2001 Au-Au beams at s=130 GeV•Open charm from PHENIX
Run II, 2002 Au-Au beams and p-p at s=200 GeV•Open charm and J/ from PHENIX
Run III, 2003 d-Au, p-p at s=200 GeV •Open charm from PHENIX and STAR, J/ from PHENIX
Run IV, 2004 Au-Au, s=200 GeV•More measurements to come
Heavy Flavor Physics at RHIC
STAR: Large acceptance TPC+EMC
Heavy Flavor Physics at RHIC
Au-Au Event in STAR
Heavy Flavor Physics at RHIC
PHENIX Physics Capabilities
• 2 central arms: electrons, photons, hadrons– charmonium J/, ’ ee
– vector meson ee – high pT
– direct photons– open charm – hadron physics
• 2 muon arms: muons– “onium” J/, ’, – vector meson – open charm
• combined central and muon arms: charm production DD e
• global detectors
forward energy and multiplicity– event characterization
designed to measure rare probes: + high rate capability & granularity+ good mass resolution and particle ID- limited acceptance
Au-Au & p-p spin
Heavy Flavor Physics at RHIC
Au-Au and d-Au events in the PHENIX Central Arms
Au-Au d-Au
Heavy Flavor Physics at RHIC
Open charm in pp: Single electrons
PHENIX: three methods to subtract
photonic background STAR: three methods to identify
electrons
p + pd + Au
PHENIX PRELIMINARY
charm cross sections (barely) agree!
NNcc =1.36 ± 0.20 ± 0.39 mb
Heavy Flavor Physics at RHIC
Consistency between electron data sets
• STAR slightly above PHENIX
Heavy Flavor Physics at RHIC
Does the PYTHIA “extrapolation” work?PYTHIA tuned to available data (sNN < 63 GeV) prior to RHIC results
PHENIX PRELIMINARY
spectra are harder than PYTHIA extrapolation from low energies Use parametrization for Au-Au reference Use rapidity dependence from PYTHIA to extract cross section
1Phys. Rev. Lett. 88, 192303 (2002)
Heavy Flavor Physics at RHIC
Reconstruction of D mesons in dAu Collisions
D0+D0
0 < pT < 3 GeV/c, |y| < 1.0
d+Au minbias
= 1.12 ± 0.20 ± 0.37 mb from D data (1.36 ± 0.20 ± 0.39 mb with electrons)
NNcc
Heavy Flavor Physics at RHIC
15 fm b 0 fm0 Npart 394
Spectators
Participants
For a given b, Glauber model predicts Npart (No. participants)and Nbinary (No. binary collisions)
Collision Geometry -- “Centrality”
0 Nbinary 1200
Heavy Flavor Physics at RHIC
Experimental Determination of Centrality
ZDC
ZDC BBC
Au Au
BBC
ZDC: zero degree calorimeter
BBC: beam-beam counter
Heavy Flavor Physics at RHIC
Almond shape overlap region in coordinate space
Selected Results: Elliptic Flow
Origin: spatial anisotropy of the system when created, followed by multiple scattering of particles in the evolving system spatial anisotropy momentum anisotropy
v2: 2nd harmonic Fourier coefficient in azimuthal distribution of particles with respect to the reaction plane
2cos2 vx
y
p
patan
Outgoingparticle
Heavy Flavor Physics at RHIC
E. Shuryak
Heavy Flavor Physics at RHIC
Adler et al., nucl-ex/0206006
Large v2
• Hydrodynamic limit exhausted at RHIC for low pT particles.
• Large magnitude of v2 suggests highly viscous “liquid”: strongly interacting nuclear medium has been
formed!
STAR v2 for charged particles
Heavy Flavor Physics at RHIC
Probing the nuclear medium formed:
Jet Suppression
charm/bottom dynamics
J/ &
direct photonsCONTROL
Heavy Flavor Physics at RHIC
Light qs and g jets as probe of the medium
hadrons
q
q
hadronsleadingparticle
leading particle
schematic view of jet production
Jets from hard scattered quarks observed via fast leading particles orazimuthal correlations between the leadingparticles
However, before they create jets, the scattered quarks radiate energy (~ GeV/fm) in the colored medium
Decreases their momentum (fewer high pT particles)Eliminates jet partner on other side
Jet QuenchingJet Quenching
Heavy Flavor Physics at RHIC
Quantify Nuclear Modification of Hadron Spectra
ddpdT
ddpNdpR
TNN
AA
TAA
TAA /
/)(
2
2
<Nbinary>/inelp+p
nucleon-nucleon cross section
1. Compare Au+Au to nucleon-nucleon cross sections2. Compare Au+Au central/peripheral
Nuclear Modification Factor:
If no “effects”: R < 1 in regime of soft physics R = 1 at high-pT where hard scattering dominates Suppression: R < 1 at high-pT
AA
AA
AA
AA
AA
AA
Heavy Flavor Physics at RHIC
Quantitative Agreement across Experiments
Effect is real…Final or Initial State Effect?
Heavy Flavor Physics at RHIC
Centrality Dependence Au-Au vs d-Au
• Significantly different and opposite centrality evolution of Au+Au experiment from d+Au control.
• Jet Suppression is clearly a final state effect.
Au + Au Experiment d + Au Control Experiment
Preliminary DataFinal Data
Heavy Flavor Physics at RHIC
Heavy Quark Energy Loss in Media
1997 Shuryak proposed that charm quarks may suffer a large energy loss
when propagating through a high opacity plasma, leading to large suppression of D mesons. (E. V. Shuryak, Phys. Rev. C 55, 961 (1997)
2001 Dokshitzer and Kharzeev propose the “dead cone” effect: Reduced gluon emission at small angles in media for heavy quarks may lead to enhancement in D meson production.
2003 Djordjevic and Gyulassy: detailed quantitative treatment of heavy quark energy loss in strongly
interacting media. Predict slight suppression: 0.6-0.8!
Y.L. Dokshitzer and D. E. Kharzeev, Phys. Lett. B 519, 199 (2001)
M. Djordjevic and M. Gyulassy, nucl-th/0310076
Heavy Flavor Physics at RHIC
Radiative heavy quark energy loss from Magdalena Djordjevic at QM 2004
There are three important medium effects that control the radiative energy loss at RHIC
1) Ter-Mikayelian effect (Djordjevic-Gyulassy Phys.Rev.C68:034914,2003)
2) Transition rediation (Zakharov)
3) Energy loss due to the interaction with the medium
1) 2) 3)
Ter-Mikayelian:
QCD analog todielectric effect
in electrodynamics
Heavy Flavor Physics at RHIC
1/T A
A
1/T A
A
1/T A
A
Centrality dependence in AuAu
No deviations from binary scaling within uncertainties.
Consistent with Djordjevic and Gyulassy: 10 x more data from Run 2004!
1/T A
A
1/T A
A1
/TA
BE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
pp reference pp reference
pp referencepp reference
pp reference
Heavy Flavor Physics at RHIC
Centrality dependence in dAu
Single electron spectra in dAu are in good
agreement with the proton reference.
PHENIX PRELIMINARY
1/T
ABE
dN/d
p3 [m
b G
eV-2]
PHENIX PRELIMINARYPHENIX PRELIMINARY
PHENIX PRELIMINARYPHENIX PRELIMINARY
1/T A
B1/
T AB
1/T A
B1/
T AB
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
1/T
ABE
dN/d
p3 [m
b G
eV-2]
Heavy Flavor Physics at RHIC
Charm flow?PHENIX PRELIMINARY
• is partonic flow realized?
• v2 of non-photonic electrons indicates non-zero charm flow in AuAu collisions
• uncertainties are large
• definite answer: RUN-04 AuAu data sample!
Heavy Flavor Physics at RHIC
J/: Does colored medium screen cc ?
0-20%most central Ncoll=779
20-40%most central Ncoll=296
40-90%most central Ncoll=45
Proton
R.L. Thews, M. Schroedter, J. Rafelski Phys. Rev. C63 054905 (2001): Plasma coalesence modelfor T=400MeV and ycharm=1.0,2.0, 3.0 and 4.0.
L. Grandchamp, R. Rapp Nucl.
Phys. A&09, 415 (2002) and Phys. Lett. B 523, 50 (2001):Nuclear Absorption+ absoption in a high temperature quark gluon plasma
A. Andronic et. Al. Nucl-th/0303036
Statistics limited:Run 2004!
Heavy Flavor Physics at RHIC
Summary
• The final state produced in central Au-Au collisions at RHIC is dense and opaque and appears to have the properties of a strongly interaction liquid.
• The energy loss of heavy quarks in nuclear media is an important tool to further characterize the nature of the medium produced at RHIC.
• Heavy flavor production will play an important role in studying nucleon structure in d-A and polarized p-p collisions at RHIC. The experimental possibilities will be greatly enhanced by silicon vertex detector upgrades for PHENIX and STAR. We expect a significant qualitative and quantitative advance from run 2004 in understanding the nature of the matter formed in central collisions at RHIC.
Heavy Flavor Physics at RHIC
PHENIX: J/e+e- and +- from pp
Central and forward rapidity measurements from Central and Muon Arms:
•Rapidity shape consistent with various PDFs•√s dependence consistent with various PDFs with factorization and renormalization scales chosen to match data
Higher statistics needed to constrain PDFs
= 3.99 +/- 0.61(stat) +/- 0.58(sys) +/- 0.40(abs) b(BR*tot = 239 nb)
Heavy Flavor Physics at RHIC
PHENIX: J/e+e- and +- from pp
•pT shape consistent with COM over our pT range
•Higher statistics needed to constrain models at high pT
•Polarization measurement limited