1. 1 Y. Miake, April.,7, 2009 @ LBNL J-Cal Overview Yasuo MIAKE Univ. of Tsukuba Extension of EM-Cal for B-to-b jet capabilities S. Esumi, T. Horaguchi H. Yokoyama, M. Sano T. Chujo

2. 2 What 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 Module 36 x 24 =864 modules (ΔΦ,Δη)~(1.0, 0.7) J-Cal

3. 5 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. 4 JCal-1 JCal-2 EMC-1 EMC-5 EMC-3 Thanks to Lars Beam View Jcal-3

5. 45 deg Thanks to Lars Side View Edge of TPC Edge of PHOS Vertex

6. 6 Physics Motivations ✓ Study of jets hopefully with PID (Parton ID) Jet quench Mach cone Tomography pedestal and flow subtracted 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. 7 Our wish ✓ We want to see mach cone with away side jet E jet > ~ 50 GeV at LHC. V.S. Pantuev, arXiv:hep-ph/0701.1882v1 RHIC LHC

8. 8 Jets; 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. 9 Key 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 (φ 1 -φ 2 ) ➡ RMS of (E jet 1 -E jet 2 ) φ1φ1 φ2φ2 E jet 1 E jet 2 R cone < 0.2 Φ JET1 -Φ JET2 PYTHIA8 p t = 40 GeV/c 80 120

10. 10 Energy 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 R cone = 0.2 γ-Jet: J-Cal - EMC J-Cal - EMC TPC - EMC PYTHIA8, detector resolution included See talk by H. Yokoyama

11. 11 Δφ B-to-b balance in φ ✓ Better phi resolution helps a lot finding jets in heavy ion environment R cone = 0.2 γ-Jet: J-Cal - EMC TPC - TPC J-Cal - EMC TPC - EMC Dijet Intrinsic PYTHIA8, detector resolution included

12. 12 Effect of the energy loss ✓ Jet energy reduces from 100 GeV to 80 GeV in central Pb+Pb at p T hat =100 GeV event PYQUEN; detector resolution not included Pb+Pb central(5%), p T hat = 100 GeV

13. 13 Effects on energy and φ balance PYQUEN, detector resolution not included See talk by H. Yokoyama

14. 14 Rates ✓ 1 month running/year ✓ 10 4 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. Esumi Thanks – Peter Jacobs From slides shown by J. Harris at Tamura Symposium, Nov. 2008 Full Dijets reconstruction by EMCAL+JCAL

15. 15 YMiake, Mar.,24, 2009 @ CERN 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. 16 Jet trigger in Pb+Pb ✓ With R cone = 0.2, triggering jet of < 50 GeV becomes difficult. ✓ Back-to back Backgrounds Fig.8.4 of TDR E jet = 100 GeV 50 GeV R cone = 0.2 R cone

17. 17 Summary ✓ 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.

18. 18 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

19. 19 Fluctuation with limitation ✓ Statistical fluctuation with total energy limitation Total jet energy is fixed. ➡ fluctuation of neutral play significant role CDF, PRL94(2005)171802 E JET =E CHARGED +E NEUTRAL E JET Charged (2/3) ~15@100Gev Fragmentation Neutral (1/3) ~7@100Gev dE CHARGED = -dE NEUTRAL

20. 20Backup

21. 21 Energy Resolution R cone = 0.2 PYTHIA8, detector resolution included R cone = 1.0

22. 22 Control variables required 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

23. 23 YMiake, Mar.,24, 2009 @ CERN Budget (Grant in Aid,JSPS) ✓ Total of ≲ 1 M$ in 5 yrs is granted. 20082009201020112012 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

24. Floor in L3 Phos Acces A side P. Panel on baby frame

25. 1565 795 770

26. 1200 1183 3700 1145

27. 27 Possibility 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 p t jet 27 CDF, PRL94(2005)171802 gluon jet quark jet

28. 28 STAR, arXiv:nucl-ex/0701074 Scenario 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/0701.1882v1

29. 29 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/0701.1882v1

30. 30 Jet Tomography ✓ Final tool to prove structure of the dense matter Positron EmissionTomography Jet Tomography M. Gyulassy ?