measurement of charm and bottom production in rhic-phenix
DESCRIPTION
Measurement of charm and bottom production in RHIC-PHENIX. Yuhei Morino for the PHENIX collaboration CNS, University of Tokyo JSPS DC fellow. Freeze-out. Hadron gas. Hadronization. QGP. Pre-equilibrium. 1.Introduction. RHIC is for the study of extreme hot and dense matter. - PowerPoint PPT PresentationTRANSCRIPT
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Measurement of charm and bottom production in RHIC-PHENIX
Yuhei Morino for the PHENIX collaboration
CNS, University of Tokyo
JSPS DC fellow
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1.Introduction
•Heavy quarks (charm and bottom) are produced at only initial stage good probe for studying property of the medium.
•p+p collisions base line study, pQCD test.•d+Au collisions initial effect study.•Au+Au collisions energy loss, flow? @ hot and dense matter
RHIC is for the study of extreme hot and dense matter.
•p+p, d+Au, Cu+Cu, Au+Au collision •√s = 22.4, 62, 130, 200 A GeV .
Freeze-out
Pre-equilibrium
QGP
Hadron gas
Hadronization
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Heavy quark measurement at PHENIX
•direct ID (invariant mass)•large combinatorial background
lepton from semileptonic decay•large branching ratio•c and b mixture
cc
0D0D-
K
direct measurement
(single&di) lepton measurement has been used for the study of heavy quarkp+p ~ Au+Au collisions
IN ADDITIONAt p+p (d+Au) collisions,direct measurement, e-h, e-correlationcan be used.important base line study.
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Inclusive electron( conversion, daliz,etc and heavy quark )
Background subtraction
Non-photonic electron(charm,bottom and minorbackground)
2 Measurement of non-photonic electron
Cocktail method
Ne Electron
yield
Material amounts:
0
0.4% 1.7%
Dalitz : 0.8% X0 equivalent radiation length
0
With converter
W/O converter
0.8%
Non-photonic
Photonic
converter
Converter method
S/N>1@pt>2GeV/c
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Phys. Rev. Lett 97,252002 (2006)
3 electron from heavy flavor (p+p@200GeV)
• Single electrons from heavy flavor (charm/bottom) decay are measured and compared with pQCD theory
• FONLL pQCD calculation agree to the data within
uncertainty.
(Fixed Order plus Next to
Leading Log pQCD)
• cc= 567 57(stat) ± 224(sys) b
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bottom fraction in non-photonic electron
•The result is consistent with FONLL•bottom component is dominant at pt>3GeV/c
2 /ndf 28.5/22 @b/(b+c)=0.42(obtained value)(0.5~5.0GeV)
be/ce is obtainedvia D e K (no PID)reconstruction
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electron spectra from charm and bottom
charm
bottom
PRL, 97, 252002 (2006)
be = (non-photonic) X (be/(ce+be))
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Heavy quark measurement via di-electron
cc
0D
0D
e
K
e-
e+
heavy quark is dominantsource @mee >1.1GeV
arXiv:0802.0050e+e- pair
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Di-electron from heavy quark
c dominant
b dominant
cocktail calculations are subtracted from data
After Drell-Yan subtracted,fit (a*charm+b*bottom)to the data.
charm and bottom cross sections from e+e- and c,be agree!
bottom, DY,subtraction charm signal !!mass extrapolation (pQCD)rapidity extrapolation (pQCD)
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4 electron from heavy flavor (d+Au@200GeV)
strong modification has notbeen observed below 3GeV/c
The yield at d+Au collisions lookslike slightly enhancednuclear anti-showing of bottom?However, there are large statisticaluncertainty for d+Au data.
The high statistics and low materiald+Au data is already collected. initial effect for heavy flavor will be revealed.
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MB
p+p
0%~
~92%
5 electron from heavy flavor(Au+Au@200GeV)
Heavy flavor electroncompared to binary scaled p+p data (FONLL*1.71)
Clear high pT suppression in central collisions
PHENIX PRL98 173301 (2007)
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Nuclear Modification Factor: RAA
tpp
tAA
colltAA dpdN
dpdN
NpR
/
/1)(
large suppression athigh pt
PHENIX PRL98 173301 (2007)
large V2 is also observed
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Comparison with models
• pQCD radiative E-loss
• langevin + D resonances
• langevin +pQCD elastic
• langevin + Tmatrix
be/ce>~1 @ pt>~3GeV/cbottom may also lose large energy in (s)QGP
alternative approaches•collisional dissociation •heavy baryon enhancement
Adil & Vitev, PLB 649(2007)139
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shear viscosity of the matter
The shear viscosity of the matter is estimated by the above two theory./s ~(1.3-2)/4near the quantum limit
Rapp and Hees et al reproduce RAAand V2 simultaneously with langevin simulation
DHQx2pT ~ 4-6
Moore and Teaney calculate the relationof viscosity between diffusion constant.
DHQ/ (/(e+P)) ~ 6
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6 Summary
• non-photonic electron spectra was obtained in p+p@200GeV• be/(ce + be) has been studied in p+p collisions at √s =200GeV via
e-h correlation. Cross section of bottom was obtained from electron spectra and be ratio
• Cross sections of charm and bottom were obtained from di-electron in p+p collisions at √s =200GeV
• High statistics d+Au@200GeV data is already collected.
• non-photonic electron spectra was obtained in Au+Au@200GeV
• large suppression pattern@high pt and large v2 was observed.
• Model comparison suggests smallτ and/or DHQ are required
• η/s is very small, near quantum bound.
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back up
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4Measurement of di-electron(Au+Au@200GeV)
c ce e dominant
Yield(1.2<mee<2.8GeV)/Ncoll
•No significant centrality dependence•consistent with PYTHIA & random cc scenarios
arXiv:0706.3034
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• Material conversion pairs removed by analysis cut
• Combinatorial background removed by mixed events
• additional correlated background:– cross pairs from decays with
four electrons in the final state– particles in same jet (low
mass)– or back-to-back jet (high
mass)
• well understood from MC
p+p at √s = 200GeVp+p at √s = 200GeV
arXiv:0802.0050
3 Measurement of di-electron(p+p@200GeV)
arXiv:0802.0050
p+p at √s = 200GeVp+p at √s = 200GeV
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4Measurement of di-electron(Au+Au@200GeV)
c ce e dominant
arXiv:0706.3034
Cocktail agrees with data [email protected]<Mee<2.8.
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total cross section of charm and bottom
√s dependence of cross section with NLO pQCDagrees with data
total cross section of bottom
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Direct measurement of D meson
Meson D±,D0
Mass 1869(1865) GeV
BR D0 --> K+- 3.85 ± 0.10 %
BR D0 --> K+-0 14.1 ± 0.10 %
BR --> e+ +X 17.2(6.7) %
•direct ID(peak)•large combinatorial background
cc
0D
0D
-
Kdirect measurement:DK, DK
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D0K-+0 reconstruction
large branching ratio(14.1%) S.Butsyk[poster]
D0K- + 0 decay channel
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electron tag reduce combinatorial background
•observe D0 peak•cross section of D is coming up
D0K-+ with electron tagtag
reconstruct
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Singnal and Background
Photon Conversion
Main photon source: → In material: → e+e- (Major contribution of photonic electron)
Dalitz decay of light neutral mesons→ e+e- (Large contribution of photonic)
The other Dalitz decays are small contributions Direct Photon (is estimated as very small contribution)
Heavy flavor electrons (the most of all non-photonic) Weak Kaon decays
Ke3: K± → e± e (< 3% of non-photonic in pT > 1.0 GeV/c) Vector Meson Decays
J → e+e-(< 2-3% of non-photonic in all pT.)
Photonic Electron
Non-photonic Electron
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Consistency Check of Two Methods
Both methods were checked each other
Left top figure shows Converter/Cocktail ratio of photonic electrons
Left bottom figure shows non-photon/photonic ratio
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Open Charm in p+p STAR vs. PHENIX
• PHENIX & STAR electron spectra both agree in shape with FONLL theoretical prediction
• Absolute scale is different by
a factor of 2
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PHENIX experiment
• PHENIX central arm:– || < 0.35 = 2 x /2– p > 0.2 GeV/c
• Charged particle tracking analysis using DC and PC → p
• Electron identification– Ring Imaging Cherenkov de
tector (RICH) – Electro- Magnetic Calorimet
er (EMC) → energy E
RNXP detector was installed at RUN7improve determination of reaction plane
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FONLL:
FONLL c/(b+c)FONLL c/(b+c)FONLL b/(b+c)
b contribution to non-photonic electron
• FONLL: Fixed Order plus Next to Leading Log pQCD calculation
Large uncertainty on c/b crossing 3 to 9 GeV/c
Measurement of be/ce is key issue.
Phys.Rev.Lett 95 122001
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decay component (~85%)kinematics
Ntag = Nunlike - N likeD0e+ K-(NO PID) reconstruction
From data
From simulation (PYTHIA and EvtGen)
Main uncertainty of c and b •production ratios (D+/D0, Ds/D0 etc)
c,b separation in non-photonic electron
background subtraction(unlike-like)•photonic component•jet component
tagging efficiency when trigger electron is detected,conditional probability of associate hadron detectionin PHENIX acc
{jet component (~15%)
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count
tagging efficiency (c,b,data)
reconstruction signal and simulation
2 /ndf 21.2/22 @b/(b+c)=0.26(obtained value)(0.5~5.0GeV)2 /ndf 28.5/22 @b/(b+c)=0.42(obtained value)(0.5~5.0GeV)2 /ndf 18.7/22 @b/(b+c)=0.56(obtained value)(0.5~5.0GeV)
•tag efficiency of charm increases as electron pt•tag efficiency of data gets near bottom
c
b
data