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

qQ

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