Physics with the ALICE TRD
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Transcript of Physics with the ALICE TRD
Physics with the ALICE TRDPhysics with the ALICE TRD
Ken OyamaKen OyamaPhysikalisches Institut, HeidelbergPhysikalisches Institut, Heidelberg
for the ALICE Collaborationfor the ALICE Collaboration
Physics at LHC, Jun.7, 2006, KrakowPhysics at LHC, Jun.7, 2006, Krakow
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 2
OverviewOverview
ALICE studies the characteristics of the quark matter produced in the Pb+Pb collisions at sqrt(sNN) = 5.5 TeV.
Expected dN/d = 1500 ~ 3000. TRD is for electron ID and trigger.
ITS TRD TPCITS TRD TPC
TRD
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 3
Physics Motivations for the ALICE TRDPhysics Motivations for the ALICE TRD
Single electron momentum spectra D e + X (17 % b.r.) B e + X … talk by R. Turrisi.
Di-electron mass spectra J/ (3.1 GeV) e+e- (6 % b.r.) ’ (3.7 GeV) e+e- (0.76 % b.r.) Y (9.5 GeV) e+e- (2.4 % b.r.) Y’ (10 GeV) e+e- (1.3 % b.r.) q+q e+e- Thermal q+q e+e- Drell-Yan
Jet spectra & shape Medium induced momentum and sh
ape modification
Information about the de-confined QGP medium state :
Color potential screening J/ suppression, Upsilon suppression
Initial scattering information and effect of the medium to it :
Jet quenching
Systematic measurements of the following observables in p+p, p+A and A+A collisions
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 4
ALICE TRD PrincipleALICE TRD Principle
Charged particles at > 1000 give T.R. photons. Thin (< 0.25 X0) detector with low power (~ 60 kW
for 1.2 M channels) readout electronics on it.
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 5
central Pb–Pb
pp
TRD: Requirements and PerformanceTRD: Requirements and Performance
Purpose : Electron ID at p > 1 GeV/c. Fast (6 s) trigger for high-pT+ PID. Improved momentum resolution.
Parameters : || < 0.9, 0 << 2 540 modules (18 super-modules) 28 m3 Xe/CO2 (85:15) 1.2 M readout channels
pT resolution < 4 %at 100 GeV/c for dNch/dy ~ 5000
simulation
beam test @ PS
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 6
SPS / RHIC SPS / RHIC LHC LHC
T<Tc
T>Tc
T>>Tc
[H. Satz, hep-ph/0602245]
Charmonium melting pattern will be seen clearly. Much larger Initial production rate will enhance the cha
rmonium yield. Strong centrality dependent secondary J/ production
by statistical hadronization J/ enhancement.
x 2
0
[P. Braun Munzinger, K. Redlich, and J. Stachel, nucl-th/0304013]
c and b Initial production rate
Overallunderstandingis necessary
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 7
J/J/ΨΨ and Upsilon Measurements (I) and Upsilon Measurements (I)
Simulation with nPDF+shadowing predicted[*] quarkonia yields embedded into HIJINGpara events (<dN/dy> ~ 3000).
Separations of J/, ’, Y, Y’ and Y’’ are possible.
10 % Centrality2x108 events106 run time (a.y.)
120k J/ S/N=1.2
900 Y S/N=1.1250 Y’ S/N=0.4
[*] A. Accardi et al.,arXiv:hep-ph/0308248
[W. Sommer, ALICE PPR]
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 8
J/J/ΨΨ and Upsilon Measurements (II) and Upsilon Measurements (II)
Momentum dependence and S/N. J/ yield can be measured for more than 10 GeV/c.
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 9
Jet Energy and Shape Measurements (I)Jet Energy and Shape Measurements (I)
hard/ tot ~ 98 % (RHIC: 50 %) [K.Kajantie, QM2002]. Leading particle energy reaches more than 100 GeV.
x1000 yield at 20 GeV compare to RHIC. In Pb+Pb:
Jet quenching as probe of medium property. Ncoll scaling violation.
Modification in jT distribution.
q
Pb
Pb
PHENIX QM2005
Phys.Lett.B595:165-170,2004e > 15 GeV/fm3; dNg/dy > 1100
Softer pT distribution Broader jT distribution Less collimation
pT
jT
vacuum
medium
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 10
Jet Energy and Shape Measurements (II)Jet Energy and Shape Measurements (II)
Effective month of running 106 s (107 central events).RC<0.4
jT: momentum transverse to the jet-direction
Underlying background from hot matter
~ 2 TeV in R < 1.0, ~ 150 GeV in R < 0.3
(assumption: dN/dy ~ 5000 and <pT> ~ 500 MeV/c).
1 ALICE year collects enough statistics of jets. Jet quenching is visible already in ET spectrum.
S/N becomes smaller than 1 at 1 GeV jT energy.
A. Morsch, ALICE PRR
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 11
Jet Triggering with TRDJet Triggering with TRD
One TRD module (size : R2 = d2 + d2 = 0.362+0.352 ~ 0.52) can count the number of high pT charged tracks available online at L1.
Expected jet rate exceeds 1 Hz for ET > 100 GeV.
Jet trigger becomes efficient at ET ~ 100 GeV where triggering is necessary t
o have statistics.
CKIN(3)=50 CKIN(3)=100 CKIN(3)=200
Expected jet rate
[D. Miskowiec]
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 12
ALICE TRD Construction Status in HeidelbergALICE TRD Construction Status in Heidelberg
Current plan of 1st super-module delivery to CERN: Aug. 15
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 13
SummarySummary
ALICE with TRD can measure Quarkonia signals (J/, ’, Y, Y’, Y’’) and st
udy properties of the Quark Gluon Plasma (good for also B-decay).
TRD can provide trigger for jet at ET > 100 GeV.
The first TRD super-module (out of 18) construction is on going. It will be
delivered to CERN in August.
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 14
Backup Slides
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 15
J/J/ΨΨ and Upsilon Measurements (III) and Upsilon Measurements (III)
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 16
Jet Shape Measurement in Other WayJet Shape Measurement in Other Way
= ln( 1/x ) = ln( ETjet / p )
(x = p / ETjet : momentum fraction) i
s sensitive for energy loss.
leading particle region
non-leading fragments region
leading particle region
<q> = 1.7 GeV2/fm 10 50
q = 2/ : transport coefficient : typical momentum transfer, : mean free path
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 17
Position and Angle ResolutionPosition and Angle Resolution
Large chambers Prototype
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 18
TRD Mechanical ConstructionTRD Mechanical Construction
Polypropylene fibers (Freudenberg LRP375BK)
Rohacell foam (HF71)
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 19
Electron Identification by TRDElectron Identification by TRD
LQ Method:
Likelihood with total charge
()(
)(
PeP
ePL
Likelihood distributionExtract probabilities
Integrated Charge
Total charge spectra
Depos. Energy (keV)
Co
un
tsMax. cluster position
Distribution of maximum cluster position
2006 Jul. 3 to 8 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration 20
Quarkonia Production RateQuarkonia Production Rate
Color Evapolation Model prediction for 5.5 TeV p+p collision[A. Accardi et al.,arXiv:hep-ph/0308248]
Ncoll scaling (Glauber model) 2.6x10-2 * ~1000 26Shadowing (EKS98)Branching ratio