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Comprehensive study of heavy quark production by PHENIX at RHIC Youngil Kwon Univ. of Tennessee For...
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Transcript of Comprehensive study of heavy quark production by PHENIX at RHIC Youngil Kwon Univ. of Tennessee For...
Comprehensive study of heavy quark production by PHENIX at RHIC
Youngil KwonUniv. of Tennessee
For the collaboration
21st Winter Workshop on Nuclear Dynamics Breckenridge, Colorado , 5-12 February, 2005
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 2
Outline
• Physics Motivations• RHIC & PHENIX• Open heavy-flavor charm measurements
– method– selected results for non-photonic e± production from
• p+p collisions at √s = 200 GeV
• d+Au collisions at √sNN = 200 GeV as a function of centrality
• Summary & Outlook
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 3
Physics Motivations
Fundamental quest : Test prediction of the parton model and pQCD, and address limitations of them. Scenarios in discussion For the collisions of p + p collisions Is mass of charm quark heavy enough? Can pQCD be applied to charm production? J.C.Collins, D.E.Soper, G.Sterman, Nucl. Phys. B263, 37(1986)
For the collisions of d+Au collisions Does “binary scaling” work?
If charm producing process is point-like and there’s no modification of initial parton distribution, they will scale.
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 4
J.C.Collins,D.E.Soper and G.Sterman, Nucl. Phys. B263, 37(1986)
d[A+BX] = ij f
i/Af
j/B d [ijcc+X] D
cH
+ ...
Factorization
fi/A,fj/B
: distribution function for point-like parton i,j
DcH
: fragmentation function for c
d [ijcc+X] : parton cross section
+ ... : higher twist (power suppressed by
QCD/m
c, or
QCD/p
t if p
t ≫m
c ) :
e.g. "recombination" E.Braaten, Y.Jia, T. Mehen, PRL, 89 122002 (2002)
Hard processes and factorization
Process independentProcess independent
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 5
Application to nuclei
fi/Au
79 fi/p
+ 118 fi/n
197 fi/N
fi/d
fi/p
+ fi/n
2 fi/N
Parton distribution for Au and d :
d+Au
Au+Au
This scaling does not work for high pt particles in central Au+Au collisions! PHENIX, PRL, 91, 072303 (2003)
For the interaction between point-like particles,
Cross section number of colliding nucleon pairs, Ex) 197 * 2 for the d+Au collisions!
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 6
RHIC• RHIC (Relativistic Heavy Ion Collider)
– Dedicated to heavy ion physics & spin studies– 4 experiments– 100+100 GeV/A for various combinations of nuclei– p+p up to 500 GeV– Variable incident
energy
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 7
PHENIX
Optimized for
lepton measurements
two central electron/photon/hadron spectrometers
electrons: central arms measurement range:
0.35 p 0.2 GeV/c
two forward muon spectrometers
muons: forward arms muon measurement
in range: 1.2 < || < 2.4 p 2 GeV/c
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 8
BBC
PHENIX, Detectors for centrality
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 9
PHENIX, Acceptance for Particles
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 10
measurement
How to measure open charm and bottom
Semi-leptonic decays contribute to single lepton spectra.
c c
K
Semileptonic decay0D
Fragmentation
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 11
e-measurement, Sources
Charm decays Beauty decays
Non-PHOTONIC Signal
Photon conversions :
Dalitz decays of 0,,’,,0ee, ee, etc) Kaon decays Conversion of direct photons Di-electron decays of ,, Thermal di-leptons
Most background is PHOTONIC
Background
0 e+e-
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 12
e-measurement, Signal Extraction (I)Mininum Bias Au+Au in sNN=200GeV
Inclusive e/photonic eNe
0
1.1% 1.7%
Dalitz : 0.8% X0 equivalent
0
With converter Conversion in converter
W/O converter Conversion from detector
0.8%
Non-photonic
• Non-photonic signal relative to photonic electrons depends on pT & collision system .
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 13
• excess above cocktail–increasing with pT
–expected from charm decays
• attribute excess to semileptonic decays of open charm
e-measurement, Signal Extraction (II)
PHENIX: PRL 88(2002)192303
conversion
0 ee
ee, 30
ee, 0ee
ee, ee
ee
’ ee
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 14
1 : Hadrons, interacting and absorbed (98%), 3 : Hadrons, penetrating and interacting (“stopped”)4 : Hadrons, “punch-through”, 2 : Charged /K's, “decaying” before absorber (≤1%), 5 : Prompt muons, desired signal
TrackerIdentifier Absorber
Collision range
Collision
Muon HadronAbsorber
Symbols
Detector
1
-measurement, Sources
23
4
5
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 15
-measurement, Signal level3
[arb
. u
nit
]
An illustration of strength,Major background vs signal
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 16
-measurement, Signal Extraction (
arb
. U
nit
)
Generator
1. Hadron measurement. by central arm,
2. Extrapolation to muon arm acceptance.
3. Simplified spectrometer geometry.
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 17
Inclusive e±, p+p at √s = 200 GeV
Following plots for p+p results from S. Butsyk’s dissertation.
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 18
“Non-photonic” Electron Invariant Cross section from Converter Subtraction
Good agreement between two independent methods
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 19
Final “Non-photonic” Electron Invariant Cross section
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 20
Comparison, PYTHIA
• PYTHIA parameters, tuned to describe the existing s < 63 GeV p+N world data– PDF – CTEQ5L– mC = 1.25 GeV– mB = 4.1 GeV– <kT> = 1.5 GeV– K = 3.5
• Total cross section from PYTHIA CC = 0.658 mb BB = 3.77 b
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 21
Comparison, FONLL
• Mateo Cacciari, private communication.
FONLL : Fixed Order next-to-leading order terms and Next-to-Leading-Log
large pT resummation.
• Central theory curve underpredict data by
a factor of 2-3 when pT > 1.5 (GeV/c).
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 22
non-photonic e±, d+Au at √sNN = 200 GeV
PHENIX PRELIMINARY
1/T
ABE
dN
/dp
3 [m
b G
eV
-2]
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 23
Centrality & Glauber Model
NBBC
coun
t coun
t
Ncoll
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 24
Centrality (in)dependence in d+Au collisions
PHENIX PRELIMINARY
PHENIX PRELIMINARYPHENIX PRELIMINARY
PHENIX 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]
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 25
Summary & Outlook
Near future :– + Single muons at forward rapidity.– + Significant increase in statistics. Significant
improvements in systematic and statistical uncertainty.
PHENIX measured non-photonic electron production at mid-rapidity in p+p at √s = 200 GeV and d+Au at √sNN = 200 GeV. NLO pQCD underpredicts production in p+p when pT > 1.5 (GeV/c). This suggests limitation of pQCD-based approach for charm production. Observed “binary scaling” in d+Au is consistent with the point-like interaction for charm production. Improvements of error bars and measurement at the extended kinematic region, i.e. forward measurement, are highly desired.
Feb. 10th, 2005 WWND@Breckenridge, Y.Kwon for PHENIX 26
USA Abilene Christian University, Abilene, TX Brookhaven National Laboratory, Upton, NY University of California - Riverside, Riverside, CA University of Colorado, Boulder, CO Columbia University, Nevis Laboratories, Irvington, NY Florida State University, Tallahassee, FL Florida Technical University, Melbourne, FL Georgia State University, Atlanta, GA University of Illinois Urbana Champaign, Urbana-Champaign, IL Iowa State University and Ames Laboratory, Ames, IA Los Alamos National Laboratory, Los Alamos, NM Lawrence Livermore National Laboratory, Livermore, CA University of New Mexico, Albuquerque, NM New Mexico State University, Las Cruces, NM Dept. of Chemistry, Stony Brook Univ., Stony Brook, NY Dept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY Oak Ridge National Laboratory, Oak Ridge, TN University of Tennessee, Knoxville, TN Vanderbilt University, Nashville, TN
Brazil University of São Paulo, São PauloChina Academia Sinica, Taipei, Taiwan China Institute of Atomic Energy, Beijing Peking University, BeijingFrance LPC, University de Clermont-Ferrand, Clermont-Ferrand Dapnia, CEA Saclay, Gif-sur-Yvette IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, Orsay LLR, Ecòle Polytechnique, CNRS-IN2P3, Palaiseau SUBATECH, Ecòle des Mines at Nantes, NantesGermany University of Münster, MünsterHungary Central Research Institute for Physics (KFKI), Budapest Debrecen University, Debrecen Eötvös Loránd University (ELTE), Budapest India Banaras Hindu University, Banaras Bhabha Atomic Research Centre, BombayIsrael Weizmann Institute, RehovotJapan Center for Nuclear Study, University of Tokyo, Tokyo Hiroshima University, Higashi-Hiroshima KEK, Institute for High Energy Physics, Tsukuba Kyoto University, Kyoto Nagasaki Institute of Applied Science, Nagasaki RIKEN, Institute for Physical and Chemical Research, Wako RIKEN-BNL Research Center, Upton, NY
Rikkyo University, Tokyo, Japan Tokyo Institute of Technology, Tokyo University of Tsukuba, Tsukuba Waseda University, Tokyo S. Korea Cyclotron Application Laboratory, KAERI, Seoul Kangnung National University, Kangnung Korea University, Seoul Myong Ji University, Yongin City System Electronics Laboratory, Seoul Nat. University, Seoul Yonsei University, SeoulRussia Institute of High Energy Physics, Protovino Joint Institute for Nuclear Research, Dubna Kurchatov Institute, Moscow PNPI, St. Petersburg Nuclear Physics Institute, St. Petersburg St. Petersburg State Technical University, St. PetersburgSweden Lund University, Lund
*as of January 2004
12 Countries; 58 Institutions; 480 Participants*