1Y. Miake, April.,7, 2009 @ LBNL

J-Cal OverviewJ-Cal Overview

Yasuo MIAKEUniv. of Tsukuba

Extension of EM-Cal forB-to-b jet capabilities

S. Esumi, T. HoraguchiH. Yokoyama, M. SanoT. Chujo

2

What is J-CalWhat is J-Cal✓J-Cal consists of 3 super modules of

the EMCAL

• Same design, same material, same

electronics as the ALICE EMCAL

✓J-Cal sits on the other side of ALICE

EMCAL detecting Back-to back jet

J-Cal, extension of EM-Cal coverage

for Jets !!

J as Jet, Japanese,,,

2

module

(ΔΦ,Δη) ~ (0.025,0.025)

3 Super Module36 x 24 =864 modules

(ΔΦ,Δη)~(1.0, 0.7)

J-Cal

5

Where is J-Cal Where is J-Cal Where is J-Cal Where is J-Cal

✓In φ, it is on the other side

of ALICE EMCAL

✓In η, it is next to the PHOS

eta view of ALICE & J-CAL

J-Cal

ALICE EMCAL

eta view of ALICE & J-CAL

3 super module(ΔΦ,Δη) ~(1.0, 0.7)

4

JCal-1JCal-2

EMC-1

EMC-5

EMC-3

Thanks to Lars

Beam View

Jcal-3

45 degThanks to Lars

Side View

Edge of TPC

Edge of P

HO

S

Vertex

6

Physics MotivationsPhysics Motivations

✓Study of jets hopefully with PID (Parton ID)

•Jet quench

•Mach cone

•Tomography

pedestal and flow subtracted

PHENIX, arXiv:0705.3238 [nucl-ex]PHENIX, arXiv:0705.3238 [nucl-ex]

J-Cal improve Back-to back jets performance in ALICE

Define B-to-B jets Trigger B-to-B jets

7

Our wishOur wish

✓ We want to see mach cone with away side jet Ejet > ~ 50 GeV

at LHC.

V.S. Pantuev, arXiv:hep-ph/0701.1882v1V.S. Pantuev, arXiv:hep-ph/0701.1882v1

RHIC LHC

8

Jets; Gamma-Jet & DiJetJets; Gamma-Jet & DiJet

✓Gamma-Jet

• Quark Jet

• Easier analysis

(no energy loss for gamma)

• Smaller rate

• Inclusive meas.

• Reaction plane dependence

✓Di-Jet•Mostly Gluon Jets

•x1000 higher rate, thus higher statistics

•Semi-exclusive meas. can be done w.r.t. reaction plane, centrality & pt of jets

Partonic Energy Loss

9

Key issues; resolutionsKey issues; resolutions

✓Good characteristics of

Back-to back jets

•Origins clean

•Kinematically clean Energy balance

back-to back in phi

✓Need to have better

resolutions RMS of (φ1-φ2)

RMS of (Ejet1-Ejet

2)

φ1

φ2

Ejet1

Ejet2

Rcone < 0.2

ΦJET1-ΦJET2PYTHIA8

pt = 40 GeV/c 80 120

10

Energy resolutionEnergy resolution

✓Statistical fluctuation in

neutrals determines the

resolution.

✓J-Cal improves the

resolution from ~45%

to ~35%

✓Imbalance in energies

provides information on

the partonic energy

loss. Dijet Intrinsic

TPC - TPC

Rcone = 0.2

γ-Jet: J-Cal - EMC

J-Cal - EMC

TPC - EMC

PYTHIA8, detector resolution included

See talk by H. Yokoyama

11

Δφ B-to-b balance in φΔφ B-to-b balance in φ

✓Better phi

resolution helps a

lot finding jets in

heavy ion

environment

Rcone = 0.2

γ-Jet: J-Cal - EMC

TPC - TPC

J-Cal - EMC

TPC - EMC

Dijet Intrinsic

PYTHIA8, detector resolution included

12

Effect of the energy lossEffect of the energy loss

✓Jet energy reduces from 100 GeV to 80 GeV in central Pb+Pb at

pThat =100 GeV event

PYQUEN; detector resolution not included

Pb+Pb central(5%), pThat = 100 GeV

13

Effects on energy and φ Effects on energy and φ balancebalancePYQUEN, detector resolution not included

See talk by H. Yokoyama

14

RatesRates

✓1 month running/year

✓104 events/year

✓Using Day-1 ALICE with J-

Cal

•Establish Dijets Axis

up to100~150 GeV

✓3 orders of magnitude

larger than gamma-Jet

See talk by S. EsumiThanks – Peter Jacobs

From slides shown by J. Harris at Tamura Symposium, Nov. 2008

Full Dijets reconstruction by EMCAL+JCAL

15YMiake, Mar.,24, 2009 @ CERN

J-Cal doubles γ-Jet yield J-Cal doubles γ-Jet yield

• γin PHOS and J-cal, jet in

EM-Cal.

• Thanks to Peter Jacobs

✓J-Cal doubles rate of γ-Jet

✓leading pi0 may be

improved by a factor of

10!

• Need simulations

Thanks to Peter Jacobs

J-X

16

Jet trigger in Pb+PbJet trigger in Pb+Pb

✓With Rcone = 0.2, triggering jet of < 50 GeV becomes

difficult.

✓Back-to back

Backgrounds

Fig.8.4 of TDR

Ejet = 100 GeV

50 GeV

Rcone = 0.2

Rcone

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SummarySummary✓J-Cal (EM) for back-to back jet performance

Improve

Resolutions ; ~45% to ~35 %

Acceptances ; 3 x γ-jets

Trigger ; (to be done)

✓Funding

•At least 1 SM EMC is already granted at Tsukuba.

•The rest of the money in negotiation.

✓Full collaboration (asking help) with US-EMCal • Dec, 2008, T.Chujo w. 2 students @ Wayne State

• Arp, 2009, 2 students (M. Sano, H. Yokoyama) stay 2 months @LBNL

• J-Cal proposal at the next ALICE week (June, 2009), see talk by Y. Miake.

• Preparation for the analysis tool at Tsukuba, see talk by T. Horaguchi.

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F. A. Q.F. A. Q.

✓Why not with PHOS?

•For jets, eta coverage of PHOS is too narrow.

•Cone radius of >0.2 needed

•J-Cal + Phos works better

✓Why not with γ-Jet?

•Rates.

• DiJets & γ-Jet will play complimental role

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Fluctuation with limitationFluctuation with limitation

✓Statistical fluctuation with total energy limitation

•Total jet energy is fixed.

fluctuation of neutral play significant role

CDF, PRL94(2005)171802 EJET=ECHARGED+ENEUTRAL

EJET

Charged(2/3)

~15@100Gev

Frag

men

tatio

n

Neutral(1/3)

~7@100Gev

dECHARGED = -dENEUTRAL

20

BackupBackup

21

Energy ResolutionEnergy Resolution

Rcone = 0.2

PYTHIA8, detector resolution included

Rcone = 1.0

22

Control variables requiredControl variables requiredfor Heavy Ion Exp.for Heavy Ion Exp.

✓Since heavy ion collisions is so complicated, while

there is no ‘standard model’, we need to measure

heavy ion collisions w. many control variables.

•Centrality / impact parameter of collisions

•Reaction Plane Angle

•Yet, another control variable for the next generation

experiments ;

→ Jet Axis

23YMiake, Mar.,24, 2009 @ CERN

Budget (Grant in Aid,JSPS)Budget (Grant in Aid,JSPS)

✓Total of ≲1 M$ in 5 yrs is granted.

2008 2009 2010 2011 2012

開発・試験

検出器製作

陽子・陽子衝突における測定と研究

鉛・鉛衝突における測定と研究

設計計算

成果発表

テスト実験

搬入

測定器完成

D1 渡邊健悟M2 佐野正人M2 坂田洞察M1 横山広樹M1 浜田英太郎M1 梶谷緑M1 轟木M1 木村瑞希

2008.4.1現在

トリガー導入

最終製作図面

個別要素試験

システムテスト

第１モジュール

第２モジュール

第３モジュール

第４モジュール

解析プログラム開発

GEANT4開発

トリガープログラム開発

トリガープログラム試験

ｐｐ物理解析・評価

PbPb物理解析・評価 Tomography解析

Floor in L3

Phos

Acces A side

P. Panel on baby frame

1565

795

770

1200

1183

37001145

27

Possibility of Parton IDPossibility of Parton ID

✓As a new generation exp.,

from Particle ID to Parton

ID !

•According to CDF exp.,

charged/neutral works

✓Might be very difficult in

heavy ion environment

✓Nevertheless, challenge!

✓It becomes feasible for

higher pt jet 27

CDF, PRL94(2005)171802

gluon jet

quark jet

28

STAR, arXiv:nucl-ex/0701074STAR, arXiv:nucl-ex/0701074

Scenario at RHICScenario at RHIC

✓Claims• Stopped parton is the source of

ridge as well as Mach cone.

• This happens only at the surface

• There should be velocity boost at the ridge region (pi,K,p)

• v3 components independent of R.P.

V.S. Pantuev, arXiv:hep-ph/0701.1882v1V.S. Pantuev, arXiv:hep-ph/0701.1882v1

29

At higher energies, At higher energies,

✓Dijets with energy un

✓Mach cone with away

side jet.

✓Higher, the better;

•Clear separation in

momentum and φ

V.S. Pantuev, arXiv:hep-ph/0701.1882v1V.S. Pantuev, arXiv:hep-ph/0701.1882v1

30

Jet TomographyJet Tomography

✓Final tool to prove structure

of the dense matter

Positron EmissionTomographyJet Tomography

M. Gyulassy ?