M.A. Lisa STAR IVth Rencontres du Vietnam, July 20001 The STAR Experiment at RHIC - First Collisions...

IVth Rencontres du Vietnam, July 2000 1

M.A. LisaSTAR

The STAR Experiment at RHIC - First CollisionsM.A. Lisa, for the STAR Collaboration

Overview Y1 configuration Performance First collisions! Y1 plans


M.A. LisaSTAR

STAR Institutions

England:

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

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


M.A. LisaSTAR

STAR


M.A. LisaSTAR

Geometry of STAR

ZCal

Barrel EM Calorimeter

Endcap Calorimeter

Magnet

Coils

TPC Endcap & MWPC

ZCal

FTPCs

Vertex Position Detectors

Central Trigger Barrel or TOF

Time Projection Chamber

Silicon Vertex Tracker

RICH


M.A. LisaSTAR

STAR Detector Acceptances(1st Year)

FTPC TPC

RICH

EMC

CTB Trigger MWCMWC

ZDC ZDC


M.A. LisaSTAR

FTPC

STAR Detector Acceptances(2nd Year)

FTPCTPC

RICH

EMC

TOF

SVT


M.A. LisaSTAR

Silicon Vertex Tracker• 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

• FULL SVT IN BEAM LATER IN YEAR

• Silicon Strip Detector (SSD) gives 4th layer between SVT and TPC; will be installed with SVT


M.A. LisaSTAR

Ring Imaging Cerenkov Counter • PID for Kaon/Pion/Proton

• 1-3 GeV/c for K/pi

• 1.5-5 GeV/c for p/anti-p

• Located at y=0 in STAR

• C6F14 Liquid Radiator

• CsI Photo Cathode

• MWPC with 16,000 Pads

Cosmic ray MIP in 1/4 of RICH(also tracked through TPC)


M.A. LisaSTAR

STAR TPC

• Prior to current run, TPC tested extensively in Summer ‘99 engineering run, with cosmic rays, laser events

• 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


M.A. LisaSTAR

Track ReconstructionPosition resolution

(cosmic rays)

Reconstructed Laser Event

Momentum resolution (cosmics)

~ 500 m


M.A. LisaSTAR

First Trigger - Zero Degree Calorimeter

“single n”

West ZDC Sum

• common to all RHIC experiments• luminosity measure• centrality measure• low-level trigger

Sum

med

CT

B

(vertex in TPC)

Summed ZDC

Sum

med

CT

B

ZDC West ZDC East


M.A. LisaSTAR

Peripheral Au+Au Collision at 130 AGeV

Data Taken June 25, 2000.

Pictures from Level 3 online display.


M.A. LisaSTAR

Au on Au Event at CM Energy ~ 130 AGeV

Data Taken June 25, 2000.

Pictures from Level 3 online display.


M.A. LisaSTAR

Au on Au Event at CM Energy ~ 130 AGeVData Taken June 25, 2000.


M.A. LisaSTAR

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


M.A. LisaSTAR

Particle Identification via dE/dx in TPC - June 2000

Approaching expected5% resolution in dE/dx

Preliminary


M.A. LisaSTAR

Topological Strangeness Measurements

−+ π+π→0sK

+π+→Λ p

−− π+Λ→Ξ−π+→ p

p TA

rm

K+


M.A. LisaSTAR

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 π, K, p (1 y 1)

• Particle Spectra for identified particles

• K/π ratios (1 y 1)

• p/¯p ratios (1 y 1)

• Neutral particle decays Λ’s, K0’s, .

• Λ/Λ ratios

• Particle correlations (HBT)

• Flow

• Correlated observables for event classes


M.A. LisaSTAR

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 ’s

• Investigate the Plethora of Particles in 1 - 2 GeV Mass Range

(cannot be fit by QCD)


M.A. LisaSTAR

STAR RHI Physics ProgramInitial Conditions

• Nuclear (q and g) structure functions, nuclear shadowing

PQCD Probes

• Parton (jet, mini-jet, high Pt particle) propagation/attenuation in matter

• High Pt spectra (gluon versus quark jet production)

EM Probes

• Virtual photons (e+e-)

Probes of Deconfinement

• J/P suppression (e+e-)

• Flavor equilibrium (strangeness saturation, multiply-strange baryons)

• Critical (non-statistical, dynamical) fluctuations

Probes of Chiral Restoration

• Resonance widths, masses, and branching ratios

• Isospin fluctuations, disoriented chiral condensates (charge to neutral ratios)

Kinematic Probes

• Hadronic p.I.d. spectra (y, Pt) - thermalization (T, B, s, s, …) and freeze-out

• HBT - space-time evolution (possible phase change)

• E-by-E (Pt, HBT, collective flow, strangeness content - i.e. T, B, s, s, …)

• Anti-baryons, anti-nuclei


M.A. LisaSTAR

Overview of STAR Physics in the 2nd Year• Additional physics beyond Year 1

– charged hadrons at low Pt (with SVT)

– multiply-strange baryon (Ξ yields & slopes (with SVT)

– increased statistics for strange particles (with increase in efficiency of SVT)

– πo 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)

• 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 G(x)

requires spin rotators at STAR & jet triggering


M.A. LisaSTAR

STAR is On-line!


M.A. LisaSTAR

Rough STAR Data Acquisition Rates

Trigger Event Size rate (~1%Lo) ~ Bandwidth events in 4 wks

( = 25%)

Central 20 MS ~ 1 / s 90% 18 MB/s 0.5 M

(5% geo)

Min. Bias 1 MB ~ 20 / s 10% 2 MB/s 1.0 M

(95% geo)

(P,PP) 0.2 MB ~ 2 / s 5% 1 MB/s 1.0 M

Design luminosity: 0.2 mb-1 sec-1

T ~ 6 b --> 1200 collisions/sec --> 60 central (5% T) collisions/sec


M.A. LisaSTAR

STAR Detector (year-by-year) 1st year detectors (now) year-by-year implementation until 2003

2nd year detectors installation in 2003

ZCal

Silicon Vertex Tracker *

Central Trigger Barrel+ TOF patch

FTPCs (1 + 1)

Time Projection Chamber

Barrel EM Calorimeter

Vertex Position Detectors

Endcap Calorimeter

Magnet

Coils

TPC Endcap & MWPC

ZCal

RICH * yr.1 SVT ladder


M.A. LisaSTAR

STAR Year 1 Detector Configuration• Baseline Detector

– Solenoid Magnet

– TPC and Electronics

– DAQ and Online

– Trigger Detectors

• Central Trigger Barrel

• Multi-wire Chamber Readout

• Zero Degree Calorimeter

• RICH ~10 msr at yc.m.

– - 0.3 < < 0.3, = 20º

• EMC ~ 4 % of eventual ( = 2, = 2π) coverage

– 0 < < 1, = 24º

• FTPC - 1 of 2 to be installed in Spring 2000

– 2.5 < < 4.0, = 2π• Level 3 Trigger

– presently 1 processor per two TPC sectors (x 2 by Summer)


M.A. LisaSTAR

STAR Year 2 Detector Configuration(additions)

• Baseline Detector (Magnet, TPC, Trigger detectors, DAQ, Online)

• RICH ~ 10 msr at yc.m.

• EMC increase to ~ 30 % of eventual (-1 < || < 1, = 2π) coverage

• SVT - -1 < || < 1, = 2π

• FTPC #2 - 2.5 < || < 4.0, = 2π

• TOF Patch - 0 < < 1, = 6º

• Level 3 Trigger

– 2 processors per TPC sector


M.A. LisaSTAR

Magnet - Status

• The Magnet has achieved full field operation• Full field (0.5 T) and half-field mapping completed• Field features were measured down to the 1-2 Gauss

K. FoleyS. Trentalange

Radius Z Axis

BR Measurements


M.A. LisaSTAR

The Forward TPCs• 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


M.A. LisaSTAR

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.


M.A. LisaSTAR

End Cap EM Calorimeter

• Lead/scintillator projective towers; with shower max

• Funded by NSF, Indiana Univ.; IUCL; DOE

• Design almost complete

• Successful test of prototype in SLAC beam in Oct. 99

• Actual construction about to begin

• Goal: install in summer 2002


M.A. LisaSTAR

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


M.A. LisaSTAR

M.A. Lisa STAR IVth Rencontres du Vietnam, July 20001 The STAR Experiment at RHIC - First Collisions...

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