Upload
astra
View
28
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Status and Implications of PID measurements at high p T. Olga Evdokimov University of Illinois at Chicago. Outline. The motivation: Where we are: current picture High p T – What? Where? Why? Identified particles at high p T : The identified particle measurements - PowerPoint PPT Presentation
Citation preview
Status and Status and Implications of PID Implications of PID measurements at measurements at
high phigh pTTOlga Evdokimov
University of Illinois at Chicago
OutlineOutline
The motivation: Where we are: current pictureHigh pT
– What? Where? Why?
Identified particles at high pT:
The identified particle measurementsImplications and Theoretical input Open questions
Summary
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
2
Medium properties via jetsMedium properties via jets
Energy loss mechanisms: need discriminative measurements
Path length effects non-trivial: need discriminative measurements
Flavor/color-charge dependence of parton-medium coupling In-medium fragmentation/ hadronization
…..
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
hadrons
q
q
hadrons
leadingparticle
leading particle
Jet Tomography: calibrated (?) probes
Described by pQCDParticle production in hard sector
convolution of PDF NLO FF
3
Define “high”Define “high”
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
CDF Collaboration, PRD 65, 072005, 2002.
In pp: inclusive cross-section is dominated by jet production above ~4 GeV/c
What about RHIC matter?
Quick look at intermediate pT: “Lingering” hydro flow Baryon anomaly Ridge
T.Hirano, Y.Nara, PRC69,034908(2004)
4
Jet quenching at RHICJet quenching at RHICNuclear Modification Factors
Jet quenching evident in strong suppression of high pT hadrons
Multiple models provide a successful descriptions of the suppression levels
Most include radiative and collisional energy loss
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
Fits: G. Qin et al, PRL100:072301, 2008
RAA YieldAA/Nbinary AA
Yieldpp
PHENIX 0 @ 200 GeV
rad+coll
radcoll
5
Jet quenching: Data & ModelsJet quenching: Data & Models
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
S. Bass et al, arXiv:0808.0908
* Similar results from GLV and WHDG
6
TECHQM Collaboration:Set to compare jet-quenching
scenarios with the same constraints: same nuclear profile same structure & fragmentation
functions same medium (hydro)
RAA of (h) is not very discriminating Need more differential
measurements
H. Caines
CATHIE/TECHQM-2009
Medium properties and E-lossMedium properties and E-loss
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
S. Wicks et al - NPA784:426-442,2007
S. Albino, et ak - NPB 725 (2005) 181
The real Outline: Identified particles spectra in pp and AA High-pT ratios and Nuclear modification
factors
Mass, Color-charge, Flavor effects
Heavy flavor studies Correlations with identified particles
7
The reference: The reference: and p and p
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
p+p→0+X
S.S. Adler et al, PRL 91 241803
p+p→0+X
F. Simon
hadrons
q
q
hadrons leadingparticle
leading particle
Simon, private communication
KKP: B. Kniehl, G. Kramer, P¨otter, Nucl. Phys. B597, 337 (2001)
AKK: S. Albino, B Kniehl, G. Kramer, arXiv: 0803.2768v2
DSS: D. de Florian, W. Vogelsang, F. Wagner, arXiv: 0708.3060v3 8
The reference: kaonsThe reference: kaons
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
STAR preliminarySTAR preliminary
Y. Xu SQM09
STAR preliminary
A. Timmins
SQM09
Consistent results for K0S and K
Extended kaon spectra – new constrains for FF
Direct measurements of FF: Pythia works well for K0
S , not so well for
9
Sample of RSample of RAAAA in PHENIX in PHENIX
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
C. Vale, Quark Matter 09
10
Zooming in: p and Zooming in: p and
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
PHENIX QM09:
“At high pT RCP(p) approaches RCP()”
PRELIMINARY
arXiv: 0804.4760
STAR preliminary
STAR QM08:
High pT RAA(p)>RAA()
The issue: pQCD predicts E-loss dependence on color-charge factors CA/CF = 9/4
Is there issue? @10 GeV/c: (0.60q+0.40g), p (0.05q+0.95g)11
Jet chemistryJet chemistry modificationsmodifications
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
pkπ
STAR Preliminary
W. Liu and R. Fries,
PRC 77, 054902 (2008)
pQCD expectation : RAA(p) < RAA()
Observation from central Au+Au collisions: RAA()~RAA() <RAA(K)<RAA(p) K/ (AA)>K/ (pp)
Hierarchy consistent with jet flavor conversion
parton medium interactions12
Reverses expected trend /− ratio from pp to Au+Au to
Boosts Kaon production ~ factor 2 due to abundance of QGP s-quarks
Medium-induced modificationsMedium-induced modifications
Flavor-conversions
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
W. Liu and R. Fries, PRC 77, 054902 (2008)
Reverses expected trend /− ratio from pp to Au+Au to
Boosts Kaon production ~ factor 2 due to abundance of QGP s-quarks
q gd
13
Leads to RAA() <RAA(p)
Describes decreasing trend pT for v2 for (anti)protons
Centrality dependence of proton-triggered correlations
HT contributions- direct hadron production
_q q p q
S. Brodsky, A. Sickles, PLB668 111 (2008)
Energy loss for Heavy Flavor Energy loss for Heavy Flavor
Heavy quarks – calculable (?) probes for medium properties
Discriminating power for energy loss scenarios
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
Light flavor energy loss Strong suppression at high pT in RAA
Radiative vs. collisional energy loss
Open heavy flavor Smaller gluon bremsstrahlung for
heavy quarks ? Smaller suppression at high pT
14
High pHigh pTT suppression for HF suppression for HF
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
STAR PRL, 98, 192301 (2007)
RAA for non-photonic electrons (from heavy flavor decays)
PHENIX QM09
No decrease in suppression for non-photonic e
15
Energy loss for beautyEnergy loss for beauty
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
Heavy Flavor results from non-photonic electrons: Strong suppression of heavy-flavor at high pT in RAA ~ light mesons Inconsistent with radiative energy loss prediction needs collisional too
What about beauty?
Agreement on b- and c- fractions from multiple STAR & PHENIX studies b-decays contribution to non-photonic electrons: ~50% at pT~5 GeV/c
strong suppression in AA for both charm and beauty!
~25%B,75%Cmostly B
e –D0 correlation using like-sign e-K pairs
16
Mid-rapidity e + forward
Summary & OutlookSummary & Outlook
RHIC: Systematic studies of the partonic medium
Systematic studies of identified particle spectra New constrains of FF Jet-chemistry modifications in AA Jet flavor conversion / direct hadron production / ??
Ongoing challenges- Color-charge effects and jet chemistry
- High pT suppression: both Charm and Beauty?
- …………
Jan 2- 9, 2010Olga Evdokimov
University of Illinois at ChicagoWWND 2010
17