Inclusive spectra and v 2 of charged particles at high p t
13
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 1 STAR Inclusive spectra and v 2 of charged particles at high p t Kirill Filimonov LBNL for the STAR Collaboration
description
Inclusive spectra and v 2 of charged particles at high p t. Kirill Filimonov LBNL for the STAR Collaboration. Outline. Introduction Spectra from central collisions Azimuthal anisotropy Initial gluon density / energy loss. Hard probes at RHIC. leading particle. hadrons. q. q. - PowerPoint PPT Presentation
Transcript of Inclusive spectra and v 2 of charged particles at high p t
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 1STAR
Inclusive spectra and v2 of charged particles at high pt
Kirill Filimonov LBNL
for the STAR Collaboration
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 2STAR
Outline
• Introduction
• Spectra from central collisions
• Azimuthal anisotropy
Initial gluon density / energy loss
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 3STAR
Hard probes at RHIC
hadrons
q
q
hadrons
leadingparticle
leading particle
s = 130 (200) AGeV
Initial production rate from pQCD
Can be used as a tool to study bulk properties of nuclear matter- partonic energy loss
Observables: spectra (RAA/pp, cent/periph) at high pt
azimuthal anisotropy v2(pt) in non-central collisions
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 4STAR
Spectra predictions
X.N.Wang, PRC 61 (2000) 064910M. Gyulassy, I. Vitev, X.N. Wang, PRL 86 (2001) 2537
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 5STAR
Azimuthal anisotropy v2
Sensitive to initial/final conditions and equation of state (EOS) !
coordinate-space-anisotropy momentum-space-anisotropy
y
x
py
px
22
22
xy
xy )(tan,2cos 12
x
y
p
pv
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 6STAR
v2 predictions
M. Gyulassy, I. Vitev and X.N. Wang
PRL 86 (2001) 2537
1) The value of v2 at high pt sensitive to the initial gluon density!
2) Earlier stages of the evolution
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 7STAR
v2 on the Lattice!
A. Krasnitz, Y. Nara, R. Venugopalan
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 8STAR
STAR Experiment at RHIC
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 9STAR
Centrality definition
Data Summer 2000 2.0 M total trigger events, 844 K central (top 15%) 331 K good (top 5%) central for physics analysis 458 K good min bias events for physics analysis
nch - number of primary tracks in || < 0.75
~ 90% of all hadronic Au+Au interactions
central collisions
5% Central
Reconstructed vertex events
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 10STAR
pt-dependence ofcentral/minbias
pt-dependence ofcentral/peripheral
Quark Matter’01
Inclusive spectra of charged hadrons
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 11STAR
Quark Matter 01
Preliminary
v2 at high pt
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 12STAR
Centrality dependence of v2(pt)
Preliminary
Kirill Filimonov, High Pt Phenomena at RHIC, BNL, 11/1/01 13STAR
Summary
• Inclusive spectra: At high pt (>2GeV/c), the central AA spectra suppressed compared to pp collisions;
• v2 at high pt
- at pt>2 GeV/c, v2 saturates up to pt~6 GeV/c; - the value of saturation depends on centrality
QCD effects? Energy loss? Gluon saturation?
