The STAR Experiment at RHIC - First Collisions
M.A. Lisa, for the STAR Collaboration
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Overview
Y1 configuration
Performance
First collisions!
Y1 plans
M.A. Lisa
IVth Rencontres du Vietnam, July 2000
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STAR
STAR Institutions
England:
U.S. Labs:
Argonne, Berkeley, and Brookhaven
National Labs
U.S. Universities:
Arkansas, UC Berkeley, UC Davis,
UCLA, Carnegie Mellon, Creighton,
Indiana, Kent State, MSU, CCNY,
Ohio State, Penn State, Purdue,
Rice, Texas A&M, UT Austin,
Washington, Wayne State, Yale
Brazil:
Universidade de Sao Paolo
China:
IHEP - Beijing, IPP - Wuhan
University of Birmingham
France:
Institut de Recherches Subatomiques
Strasbourg, SUBATECH - Nantes
Germany:
Max Planck Institute – Munich
University of Frankfurt
Poland:
Warsaw University
Warsaw University of Technology
Russia:
MEPHI – Moscow, LPP/LHE JINR –
Dubna, IHEP - Protvino
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STAR
STAR
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STAR
Geometry of STAR
Magnet
Coils
TPC Endcap
& MWPC
Time
Projection
Chamber
Silicon
Vertex
Tracker
FTPCs
ZCal
Endcap
Calorimeter
Barrel EM
Calorimeter
ZCal
Vertex
Position
Detectors
Central Trigger
Barrel or TOF
RICH
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STAR
STAR Detector Acceptances
(1st Year)
MWC
CTB Trigger
MWC
EMC
ZDC
FTPC
TPC
ZDC
RICH
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STAR
STAR Detector Acceptances
(2nd Year)
EMC
FTPC
TPC
FTPC
SVT
RICH
TOF
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STAR
Silicon Vertex Tracker
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SVT IS A 3 LAYER VERTEX
DETECTOR WITH 216 ELEMENTS
“Solid state TPC “
~20 micron position resolution
Dec. 99--Single ladder with 7 elements
installed in STAR; 3 elements coupled to
readout
Cosmic ray data - some matching achieved
Laser generated data shows response as
expected
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FULL SVT IN BEAM LATER IN YEAR
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Silicon Strip Detector (SSD) gives 4th layer
between SVT and TPC; will be installed
with SVT
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STAR
Ring Imaging Cerenkov Counter
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PID for Kaon/Pion/Proton
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1-3 GeV/c for K/pi
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1.5-5 GeV/c for p/anti-p
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Located at y=0 in STAR
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C6F14 Liquid Radiator
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CsI Photo Cathode
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MWPC with 16,000 Pads
Cosmic ray MIP in 1/4 of RICH
(also tracked through TPC)
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STAR
STAR TPC
• Active volume: Cylinder r=2 m, l=4 m
– 139,000 electronics channels
sampling drift in 512 time buckets
On-board FEE Card:
Amplifies, samples,
digitizes 32 channels
• Prior to current run, TPC tested
extensively in Summer ‘99 engineering
run, with cosmic rays, laser events
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STAR
Position resolution
(cosmic rays)
Track Reconstruction
Reconstructed Laser Event
~ 500 mm
Momentum resolution (cosmics)
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STAR
Summed CTB
(vertex in TPC)
First Trigger - Zero Degree Calorimeter
“single n”
Summed CTB
Summed ZDC
West ZDC Sum
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common to all RHIC experiments
luminosity measure
centrality measure
low-level trigger
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STAR
Peripheral Au+Au Collision at 130 AGeV
Data Taken June 25, 2000.
Pictures from Level 3 online display.
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STAR
Au on Au Event at CM Energy ~ 130 AGeV
Data Taken June 25, 2000.
Pictures from Level 3 online display.
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STAR
Au on Au Event at CM Energy ~ 130 AGeV
Data Taken June 25, 2000.
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STAR
Au on Au Event at CM Energy ~ 130 AGeV
Data Taken June 25, 2000.
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STAR
More sophisticated triggers
Level 3 Online Diagnostic Display
This analysis is produced and
displayed in Real time (~1 sec.) as
events are taken. Additional L3 online
plots show:
• PT distribution for tracks
• Number of reconstructed hits on tracks
• Number of hits on primary tracks
• Number of reconstructed hits vs
potential number of hits
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STAR
Particle Identification via dE/dx in TPC - June 2000
Approaching expected
5% resolution in dE/dx
Preliminary
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STAR
pTArm
Topological Strangeness Measurements
K s0

 

a
  p  
     
 p  
Km+
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STAR
Expected Physics Measurements this year
Some physics measurements we expect to accomplish with this year’s data:
• dN/d for charged particles (~1.5    ~1.5)
• dN/dy for , K, p
(1  y  1)
• Particle Spectra for identified particles
• K/ ratios
(1  y  1)
• p/¯p ratios
(1  y  1)
• Neutral particle decays ’s, K0’s, .
• / ratios
• Particle correlations (HBT)
• Flow
• Correlated observables for event classes
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STAR
STAR Physics Program
Relativistic Heavy Ion Physics
• High Density QCD Matter
• QCD Deconfinement Phase Transition
• Chiral Phase Transition
Polarized Proton-Proton Interactions
• Spin Structure of the Nucleon
2-Photon Physics
• Intense EM Fields of Passing Nuclei
Coherent Source of g’s
• Investigate the Plethora of Particles in 1 - 2 GeV Mass Range
(cannot be fit by QCD)
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STAR
STAR RHI Physics Program
Initial Conditions
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Nuclear (q and g) structure functions, nuclear shadowing
PQCD Probes
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Parton (jet, mini-jet, high Pt particle) propagation/attenuation in matter
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High Pt spectra (gluon versus quark jet production)
EM Probes
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Virtual photons (e+e-)
Probes of Deconfinement
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J/P suppression (e+e-)
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Flavor equilibrium (strangeness saturation, multiply-strange baryons)
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Critical (non-statistical, dynamical) fluctuations
Probes of Chiral Restoration
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Resonance widths, masses, and branching ratios
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Isospin fluctuations, disoriented chiral condensates (charge to neutral ratios)
Kinematic Probes
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Hadronic p.I.d. spectra (y, Pt) - thermalization (T, mB, s, ms, …) and freeze-out
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HBT - space-time evolution (possible phase change)
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E-by-E (Pt, HBT, collective flow, strangeness content - i.e. T, mB, s, ms, …)
M.A. Lisa •
Anti-baryons, anti-nuclei
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STAR
Overview of STAR Physics in the 2nd Year
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Additional physics beyond Year 1
– charged hadrons at low Pt (with SVT)
– multiply-strange baryon (,W) yields & slopes (with SVT)
– increased statistics for strange particles (with increase in efficiency of SVT)
– o identification, yields, slopes(with EMC)
– high Pt triggering (with EMC)
– transverse energy measurements (with EMC)
– measurements of charged hadrons and strange particles at forward rapidities
(with FTPCs)
– increased coverage for event-by-event physics
(flow, correlations, fluctuations, dimensional analysis)
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Start modest polarized proton program
– transverse analyzing power (AT)
requires ~ pb-1 transversely polarized protons
polarimetry at RHIC (possibly STAR)
– inclusive jets  ALL which is sensitive to DG(x)
requires spin rotators at STAR & jet triggering
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STAR
STAR is On-line!
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STAR
Rough STAR Data Acquisition Rates
Trigger
Event Size
rate (~1%Lo)
~ Bandwidth
events in 4 wks
(e = 25%)
Central
(5% s geo)
20 MS
~1/s
90%  18 MB/s
0.5 M
Min. Bias
(95% s geo)
1 MB
~ 20 / s
10%  2 MB/s
1.0 M
gg (gP,PP)
0.2 MB
~2/s
5%  1 MB/s
1.0 M
Design luminosity: 0.2 mb-1 sec-1
sT ~ 6 b --> 1200 collisions/sec --> 60 central (5% sT) collisions/sec
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STAR
STAR Detector (year-by-year)
Magnet
1st year detectors (now)
implementation until 2003
2nd year detectors
year-by-year
installation in
2003
Time
Projection
Chamber
Coils
Silicon
Vertex
Tracker *
TPC Endcap &
MWPC
FTPCs (1 + 1)
ZCal
ZCal
Endcap
Calorimeter
Vertex
Position
Detectors
Barrel EM
Calorimeter
Central
Trigger Barrel
+ TOF patch
M.A.RICH
Lisa
* yr.1 SVT ladder
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STAR
STAR Year 1 Detector Configuration
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Baseline Detector
–
Solenoid Magnet
–
TPC and Electronics
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DAQ and Online
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Trigger Detectors
• Central Trigger Barrel
• Multi-wire Chamber Readout
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• Zero Degree Calorimeter
RICH ~10 msr at yc.m.
– - 0.3 <  < 0.3, Df = 20º
EMC ~ 4 % of eventual (D = 2, Df = 2) coverage
– 0 <  < 1, Df = 24º
FTPC - 1 of 2 to be installed in Spring 2000
– 2.5 <  < 4.0, Df = 2
Level 3 Trigger
– presently 1 a processor per two TPC sectors (x 2 by Summer)
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STAR
STAR Year 2 Detector Configuration
(additions)
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Baseline Detector (Magnet, TPC, Trigger detectors, DAQ, Online)
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RICH ~ 10 msr at yc.m.
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EMC increase to ~ 30 % of eventual (-1 < || < 1, Df = 2) coverage
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SVT - -1 < || < 1, Df = 2
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FTPC #2 - 2.5 < || < 4.0, Df = 2
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TOF Patch - 0 <  < 1, Df = 6º
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Level 3 Trigger
– 2 a processors per TPC sector
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STAR
Magnet - Status
BR Measurements
• The Magnet has achieved full field
operation
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Vietnam, July 2000 mapping
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• Full field (0.5 IVth
T)Rencontres
and duhalf-field
K. Foley
S. Trentalange
STAR
The Forward TPCs
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2 chambers; 1 for each end;
Radial drift TPC
First chamber assembly almost complete
with 30 readout chambers installed
HV testing in progress
FEE Board design complete
– 64 channels per board
– Smaller package for SAS & SCA chips
• Installation in fall 2000
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STAR
Barrel EMC - an AEE project
• Full Size prototype module and Shower Max
detector (SMD) successfully tested in AGS Test
Beam
• Module and SMD production ongoing; 14
modules and 24 SMD complete
• 4 modules with SMD installed in STAR; will
have prototype electronics for upcoming RHIC
run
• Production and Installation of EMC modules
will be phased over the next three years.
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STAR
End Cap EM Calorimeter
• Lead/scintillator
projective towers; with
shower max
• Funded by NSF,
Indiana Univ.; IUCL;
DOE
• Design almost
complete
M.A. Lisa
• Successful test of
prototype
in SLAC
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STAR
Projection for Next Year's Running
• Au + Au beam at top energy
(possibly at lower energy)
• Si + Si and p + p at top energy
(possibly at lower energy)
• Polarized p + p
• Possible other beam/energy changes,
depending upon what we see in this year’s data
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STAR
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