Physics objectives and performance requirements
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Physics objectives and performance requirements. L ijuan Ruan for the STAR Collaboration ( Lawrence Berkeley National Laboratory ). Outline: Performance requirements PID capability Physics objectives Summary. Performance requirements and achievements. Requirements:

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Physics objectives and performance requirements

Physics objectives and performance requirements

LijuanRuan for the STAR Collaboration

(Lawrence Berkeley National Laboratory)

Outline:

  • Performance requirements

  • PID capability

  • Physics objectives

  • Summary

DOE TOF Review, BNL, September 25, 2006


Performance requirements and achievements

Performance requirements and achievements

Requirements:

  • Good timing resolution: < 100 ps in Au+Au collisions.

  • Small occupancy per channel: < 10-15%.

  • Rate capability: 200 Hz/cm2.

  • High efficiency: > 90%.

  • Fit into CTB.

  • Safe and not impair the performance of other STAR detectors

Achievements from the prototype:

  • 86 ps timing resolution achieved in Au+Au.

  • 3 cm  6 cm, 120326 read out, large granularity

  • Rate capability: 500 Hz/cm2 (test beam, CERN)

  • High efficiency: > 95%

  • Will benefit from or enhance the performance of other STAR detectors, to be shown later

DOE TOF Review, BNL, September 25, 2006


Timing resolution summary

Timing resolution summary

  • The new method was developed to achieve better resolution, shown in red texts.

  • New electronics TOT is fine.

  • No age effect.

DOE TOF Review, BNL, September 25, 2006


Hadron electron pid capability

Hadron/Electron PID capability

TPC

|1/β-1|<0.03

electrons

Clean electron PID can be obtained up to PT < 3 GeV/c.  measure the semileptonic decay of open charm.

(STAR Collaboration, PRL94(2005)062301)

TOF PID: (, K) ~ 1.6, p ~ 3 GeV/c.

rdE/dx PID: (, p) 2.5-12 GeV/c

TOF+rdEdx PID: 0.3-5 GeV/c

STAR Collaboration, PLB616(2005)8; nucl-ex/0606003.

DOE TOF Review, BNL, September 25, 2006


Physics objectives and performance requirements

Physics topics from TOF in STAR

  • Identified hadron spectra

    • freeze-out dynamics

    • hadronization mechanism

  • Identified particle correlations

    • Chemical and kinetic properties of in-medium jet associated spectra

    • Fluctuations and correlations

  • Lepton program

    • In-medium vector meson properties

    • Heavy flavor

  • Baseline detector for future upgrades

DOE TOF Review, BNL, September 25, 2006


Pid spectra freeze out dynamics

PID Spectra – Freeze-out dynamics

STAR’s strength of measuring many particle species: exp(-(Mi-mB)/Tch)

The K(p): pT<0.75(1.1) GeV/c.

Resonant and multi-strangeness states have large errors: PID misidentification, efficiency …

Chemical freeze-out: distribution of particle species

Kinetic freeze-out: momentum spectra

DOE TOF Review, BNL, September 25, 2006


Pid physics at intermediate p t

200 GeV Au+Au STAR Preliminary

PID physics at intermediate pT

  • Number of constituent quark (NCQ)

  • Transition regime 2<pT<5 GeV/c

  • Multi-strangeness baryons

  • Heavy Mesons (K*, )

Surprising discoveries at RHIC:

Coalescence of quarks?

New hadronization mechanism?

DOE TOF Review, BNL, September 25, 2006


What can tof bring spectra efficiency background rejection

What can TOF bring – spectra, efficiency, background rejection

  • Kp pT range (1 < pT < 3 GeV/c), efficiency > 80%

  •  efficiency x 8

  • Resonances x 2--10

  • Reject correlated background due to misidentified particles.

  • Eliminate this systematic error ( 20%)

DOE TOF Review, BNL, September 25, 2006


Physics objectives and performance requirements

Physics topics from TOF in STAR

  • Identified hadron spectra

    • freeze-out dynamics

    • hadronization mechanism

  • Identified particle correlations

    • Chemical and kinetic properties of in-medium jet associated spectra

    • Fluctuations and correlations

  • Lepton program

    • In-medium vector meson properties

    • Heavy flavor

  • Baseline detector for future upgrades

DOE TOF Review, BNL, September 25, 2006


Jet quenching at rhic

Jet quenching at RHIC

  • One of the major discoveries at RHIC

  • How coalescence works?

  • Vacuum fragmentation at pT>6 GeV/c?

  • How jet energy dissipates in the medium?

DOE TOF Review, BNL, September 25, 2006


Identified baryon and meson spectra in au au collisions another publication from tof prototype

Identified baryon and meson spectra in Au+Au collisions: another publication from TOF prototype

  • particle spectra up to very high pT = 12 GeV/c.

  • TOF: pT up to 5 GeV/c,important for coalescence region.

STAR: nucl-ex/0606003,

accepted by PRL.

DOE TOF Review, BNL, September 25, 2006


Jet associated spectra correlations

Leading

hadrons

Medium

Jet associated spectra/correlations

Jet dissipates energy

  • Away-side spectra approaching the bulk

  • Chemically and thermally?

  • Need PID 1<pT<4 GeV/c Not be able to do without FULL TOF

  • Another surprise waiting for discovery?

DOE TOF Review, BNL, September 25, 2006


Correlation s

near

Medium

away

mach cone

near

Au+Au Central 0-12% Triggered

Medium

away

deflected jets

Correlations

  • Jet  Bulk

  • Three particle correlations

  • Indicates deflected jets and mach cone.

d+Au

Au+Au central

DOE TOF Review, BNL, September 25, 2006


Physics objectives and performance requirements

Identified particle hD,fDcorrelations for 200 GeV p+p using TPC dE/dx

Unlike sign

(Analysis by D. Prindle)

pp

All charges

KK

pp

Like sign

STAR Preliminary

Marginal statistics and ptcoverage with dE/dx

Large h,f acceptance TOF extends PID correlation studies to include:

- flavor and baryon dependent hadronization dynamics

- semi-hard processes in medium

- distinguish energy/thermal vs pressure/flow structures

L. Ray

DOE TOF Review, BNL, September 25, 2006


Energy scan search for the critical point

Energy scan: search for the critical point

B√sNN

———————————————————

180 MeV25 GeV

420 MeV7.5 GeV

725 MeV4.5 GeV

———————————————————

Cleymans, et.al.

J. Phys. G30 (2004) S1381

  • Energy scan: run 9

  • Mapping out the critical point: Fluctuation K/, p/  need PID, large acceptance.

DOE TOF Review, BNL, September 25, 2006


Physics objectives and performance requirements

Physics topics from TOF in STAR

  • Identified hadron spectra

    • freeze-out dynamics

    • hadronization mechanism

  • Identified particle correlations

    • Chemical and kinetic properties of in-medium jet associated spectra

    • Fluctuations and correlations

  • Lepton program

    • In-medium vector meson properties

    • Heavy flavor

  • Baseline detector for future upgrades

DOE TOF Review, BNL, September 25, 2006


Qgp signature

R. Rapp, hep-ph/0010101

QGP signature

  • Vector meson properties

  • Thermal dileptons/photons

  • Heavy flavor

R. Rapp, hep-ph/0010101

DOE TOF Review, BNL, September 25, 2006


Dilepton capability

Dilepton capability

TPC+TOF+SSD+HFT ~ 200M central Au+Au events :

22Kand 6K vector meson pairs for one year RHIC running

DOE TOF Review, BNL, September 25, 2006


Muon identification at low p t

Muon identification at low pT

0.15<pT<0.25 GeV/c, DCA < 3 cm

Nucl-ex/0607011, Y.F. Zhang et al., SQM2006.

Significantly reduce the systematic uncertainty on the charm cross section measurement.

DOE TOF Review, BNL, September 25, 2006


Prototype tof related charm results

Prototype TOF related charm results

  • Charm total cross section scales approximately with Nbin

  • Charm produced at initial impact, sensitive to the evolution/thermalization

  • Suppression at pT(e) >1.5 GeV/c  strong energy loss for charm

  • Full TOF improves (x5) charm hadronic reconstruction

    Nucl-ex/0607011, Y.F. Zhang et al., SQM2006, paper in preparation;STAR Collaboration, Phys. Rev. Lett. 94 (2005) 062301

DOE TOF Review, BNL, September 25, 2006


E from d decay d 0 e k x

e from D decay D0e+ K- X

  • D0e+ K- X

  • eK pair invariant mass and opening angle distributions from D decay is different from the combinatorial background. We use this as a tool to identify the e is from D decay.

3<pT(e)<6 GeV/c

3<pT(e)<6 GeV/c

Φ<36 degree

TOF will provide electron PID at intermediate pT and kaon identification (electron rejection at low pT) and extend kaon PID to ~2 GeV/c.

DOE TOF Review, BNL, September 25, 2006


J y at low p t

pT (e)>1.5 GeV/c

J/y at low pT

PHENIX PRC 69(2004)014901

  • Thermalization & Color DOF

    • Test color screening

    • Coalescence of charm quarks

  • PHENIX Acceptance: ||<0.35, =2  /2

  • STAR TOF-Upgrade Acceptance: ||<0.9, =2  

  • J/ Acceptance: STAR=100PHENIX

STARJ/y

PHENIXJ/y

DOE TOF Review, BNL, September 25, 2006


Baseline detector for other upgrades

Baseline detector for other upgrades

  • TOF provides 2 and ||<0.9 coverage

  • Future upgrades will benefit from or enhance the capability of this detector

  • .e.g. Heavy Flavor Tracker (HFT) and TOF can be a powerful device for dilepton and heavy flavor programs

DOE TOF Review, BNL, September 25, 2006


Critical needs from future experiments

v2 scaling for coalescence

jet quenching as parton energy loss

energy dependence testing model prediction

Heavy flavor yields and flow:color screening and partonic collectivity.

forwardjet correlation:CGC

Thermometers: dilepton, photon

heavy quarkonium species.

jet fragments tagged by a hard direct photon, a heavy flavor

elliptic flow in U+U collisions.

LHC and GSI energies

fundamental QCD symmetries

Critical needs from future experiments

Near Term

Long Term

TOF

  • PID spectra

    • freeze-outs

    • hadronization

  • PID correlations

    • In-medium jet

    • Fluctuations and correlations

  • Lepton program

    • In-medium Vector Meson

    • Heavy Flavor

  • Baseline detector for future upgrades

Near/Long Term: STAR white paper Nucl. Phys. A 757 (2005) 102

DOE TOF Review, BNL, September 25, 2006


Backup

Backup

DOE TOF Review, BNL, September 25, 2006


Star mrpc tof publications

STAR MRPC TOF publications

  • Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at 200 GeV, nucl-ex/0606003, accepted by PRL.

  • PID Cronin Effect in d+Au, Phys. Lett. B 616 (2005) 8.

  • Charm Cross section and spectra in p+p, d+Au,Phys. Rev. Lett. 94 (2005) 062301.

  • A lot of conference proceedings, QM04, SQM04, QM05, SQM06 talks.

  • Two Ph. D theses.

  • 8 NIMA publications:Nucl.Instrum.Meth.A538:243-248,2005Nucl.Instrum.Meth.A533:60-64,2004Nucl.Instrum.Meth.A492:344-350,2002Nucl.Instrum.Meth.A508:181-184,2003Nucl.Instrum.Meth.A478:176-179,2002Nucl.Instrum.Meth.A538:425-430,2005Nucl.Instrum.Meth.A537:698-702,2005Nucl.Instrum.Meth.A558:419,2006

  • More to come from prototype TOFr

    two Ph. D theses next year, 3 QM06 talks, 2 STAR papers in preparation.

  • Imagine what we can accomplish with Full TOF

DOE TOF Review, BNL, September 25, 2006


Pid identification by combining tpc tof

TPC

PID identification by combining TPC+TOF

TOF alone, (, K) ~1.6 GeV/c , p ~ 3 GeV/c.

TOF+dE/dx,  and p can be identified up to 5 GeV/c.

( ,p) 0.3~12 GeV/cM. Shao et al., NIMA 558, (419) 2006

DOE TOF Review, BNL, September 25, 2006


Reject gamma conversion

Reject gamma conversion

  • Background: g  e+e-

  • HFT discriminates background !

  • Need low mass detector

DOE TOF Review, BNL, September 25, 2006


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