1. 13 Oct 2010 29 th ALICE RRB J. Schukraft 29 th ALICE RRB Collaboration News Detector Status Physics Results CERN-RRB-2010-073

2. 13/10/2010 29 th RRB J. Schukraft 2 Collaboration News New Institutes  Comsats (Pakistan) : ‘associate members status’, Physics, Computing Applying (decision in November)  Gahauti Univ (Assam) & Bose Institute (Kolkata) Physics, Upgrades  KISTI (Korea) : ‘associate members status’ Computing Ongoing Discussions  Pinstech (Pakistan) : ‘associate members status’, Physics, Computing  small computing cluster now up & running  Egypt (initially via JINR), Lebanon (small group, associated via other ALICE institutes),

3. 13/10/2010 29 th RRB J. Schukraft 3 Collaboration News Appointments (tbc by CB in November)  Run Coordinator 2011: P. Martinengo (CERN)  Editorial Board Chair: H. Oeschler (TU Darmstadt)  Conference Committee Chair: E. Vercellin (Torino) Elections: Spokesperson & CB-chair  Spokesperson: P. Giubellino (Torino), starting 1.1.2011 for 3 year term  CB chair : P. Braun-Munzinger (GSI), starting 1.1.2011 for 3 year term  2 deputies each for SP and CB chair to be nominated in November

4. 13/10/2010 29 th RRB J. Schukraft 4 Funding.. UK funding : no news  STFC review end 2009:  ALICE support guaranteed only until the end of the current grant (mid 2011)  new grant application being prepared, prospects uncertain… CIEMAT (Spain)  new director of CIEMAT intended to withdraw from ALICE in 2010  now: reduced but continued participation in 2011  continue ongoing involvement in physics (several PhD students) & computing  USC (Santiago de Compostela) seeks independent funding starting 2012

5. 13/10/2010 29 th RRB J. Schukraft 5 ‘Upgrades’ EMCAL extension (‘DCAL’) (~ 40% of emcal)  approved in August 2010  US DOE, Japan, China, France  construction to be completed for installation in 2012 ALICE Upgrade planning  several options are under study  improved vertex dets, forward calo, PID,..  adjusting to new LHC shutdown schedule  concrete plans require first HI data  upgrades to be presented & discussed in 2011

6. 13/10/2010 29 th RRB J. Schukraft 6 ALICE Status Complete: ITS, TPC, TOF, HMPID, FMD, T0, V0, ZDC, Muon arm, Acorde PMD, PHOS(3/5), DAQ Partial installation: 7/18 TRD 4/10 EMCAL ~ 60% HLT for pp 100% HLT for Pb-Pb (+1200 CPU cores installed) ALICE Detector Configuration 2010 All systems up & running & taking data

7. 13/10/2010 29 th RRB J. Schukraft 7 ALICE Status 0 1 2 3 4 5 6 7 9 8 11 12 13 14 15 17 0 1 2 3 4 16 10 2x Installation WS 2010/11 9 week WS : very busy schedule !  install 6 EMCAL & 3 TRD modules  continuous 2 shift operation  contingency: reduced scope  very sign. physics gain !  x 2 for TRD J/   jets in emcal 10/18 TRD 10/10 EMCAL

8. 13/10/2010 29 th RRB J. Schukraft 8 Commissioning/Calibration PHOS/EMCAL  no test beam calibration => pp data  final calibration needs full 2010 stat. TRD  commissioning electron ID  pion rejection ok, e-efficiency to be improved Muon tracking  alignment constantly improving Before After PHOS  E/E ~ 7% track residuals bending plane TPC dE/dx pions electrons

9. 13/10/2010 29 th RRB J. Schukraft 9 TPC Calibration gain & drift velocity calibration very good  now working on local, static field distortions (mechanical tolerances/deformations)  track distortions reduced by factor 4-5 (< 500  m close to Field Cage)  required to go to higher momenta Track Distortions Before Corrections After Corrections

10. 13/10/2010 29 th RRB J. Schukraft 10 Material Budget Improving Detector Simulation  central part (< 45 0 ): very precisely measured (< 5%)  forward part: improved description in simulation (using design drawings/installation photo’s) Material in simulation SSD SDD SPD FMD multiplicity Not fully corrected

11. 13/10/2010 29 th RRB J. Schukraft 11 Operational Issues SPD cooling  issue since start-up, 10-20 % of modules insufficient cooling; clogged filters ?  lab test set-up to study problem and solutions now operational  filters can be accessed only in 2012 long shutdown TPC chamber HV trips  increasing trips of IROCs with increasing beam luminosity (reaching 1/few hours)  mostly not correlated with machine background; charging up of insulating parts ?  remedy: increased H 2 O (200 ppm), adding RC filters to power supply  operating now since several days without new trips; tbc HMPID radiator leak  small leak in radiator vessel found in June  flow switched of => reduction of active area by 5%  potential causes under study Pedestal stability Muon chambers/PMD  slow drift of (small) parts of the electronics baseline  no impact on physics, but increase of event size => frequent calibrations runs  remedies under study for shutdown

12. 13/10/2010 29 th RRB J. Schukraft 12 Physics & Data Taking Physics with pp  collect ‘comparison data’ for heavy ion program  many signals measured ‘relative’ to pp  requires ~ 10 9 MinBias events+few 10 pb -1 rare focus on MB; reduced L, displaced beams  now and 2011: increased L for rare processes  comprehensive study of MB@LHC  tuning of Monte Carlo (background to BSM)  soft & semi-hard QCD  very complementary to other LHC expts  address specific issues of QCD Heavy Ion run starting November  since August (ICHEP) shift effort ‘back’ to HI preparation  initial run at low Luminosity ( L < 1/20 design)  event rate ~ 10 – 100 Hz  expect ~ 10 7 MinBias events (1-3  b -1 )

13. 13/10/2010 29 th RRB J. Schukraft 13 Some Performance Plots J/  → e + e - |y| < 0.9 J/  →    , y = 2.5 - 4  →       (PHOS + TPC)  →     - hard to measure J/  with our current low L (also 1 st year Pb Lumi will be very low -> priority on MB in pp) - ‘proof of detector performance’ higher L later this year and next

14. 13/10/2010 29 th RRB J. Schukraft 14 Charm at 7 TeV (ICHEP) D 0 →  D 0 →  D + →  D * → D   D s + → Φπ + →       Impact Parameter Resolution vs p T 80  m @ 1 GeV

15. 13/10/2010 29 th RRB J. Schukraft 15 (Anti) Nuclei Distance of track to collision vertex TPC dE/dx 7 TeV pp  ≈5-6%

16. 13/10/2010 29 th RRB J. Schukraft 16 Data Taking Summary >750 Million interactions > 50 M Muon triggers Integrated data taking efficiency ~ 80% since Sept increasing to > 90% > 20 M high Multiplicity Operation: shift crew reduced from > 30 to 6 people + ~ 30 ‘on call’ experts (24h 7/7)

17. 13/10/2010 29 th RRB J. Schukraft 17 Offline Processing Raw Data Registration Reconstruction quasi on line @ T0 Further passes after calibration (T0/1) Grid Analysis average of 1150 concurrent jobs ~ 250 regular users Raw Data Processing 1.3K runs321K files756 TB Resource Usage 1 st half of 2010: excess resources now exhausting allocated CPU 45% (15%) of allocated disk in T1(T0) HI data still to come.. reconstruction:6% analysis: 13% MC: 81%

18. 13/10/2010 29 th RRB J. Schukraft 18 Results Final Results  N ch multiplicity & distributions  900 GeV: EPJC: Vol. 65 (2010) 111  900 GeV, 2.36 TeV: EPJC: Vol. 68 (2010) 89  7 TeV: EPJC: Vol. 68 (2010) 345  pbar/p ratio (900 GeV & 7 TeV)PRL: Vol. 105 (2010) 072002  Momentum distributions(900 GeV) PLB: Vol. 693 (2010) 53  Bose-Einstein correlations (900 GeV) PRD: Vol. 82 (2010) 052001 Ongoing analyses  7 TeV event properties: spectra, HBT, identified particles, strangeness, high multiplicity  Heavy flavour: charm (D 0,D +, D*), heavy quarks (c,b)  e -  J/  e + e -  pQCD: Event topology, 2-particle correlations, jet fragmentation, … Under Collaboration Review  Identified particles ( ,K,p)  Strangeness (K 0, , , ,  Global event properties Comparison Data clarifies QCD issue

19. 13/10/2010 29 th RRB J. Schukraft 19 Kaon p T distributions stable & decays K →  K 0 S →  Identified Particles Identified Particle p T  K p ITS dE/dx TPC dE/dx TOF

20. 13/10/2010 29 th RRB J. Schukraft 20  Stable: , K, p at 900 GeV Prel. Results: - very large K/  ratio at high p T - not reproduced by event generators

21. 13/10/2010 29 th RRB J. Schukraft 21 Decays: K 0 S  at 900 GeV * Prel. Results: - MC well below Data - more so at high p T - more so for  -  ~ ok (at least some MC) K 0 S →   → p   → K K  →  * 2009 Data (~300 k events)

22. 13/10/2010 29 th RRB J. Schukraft 22  /K 0 S Ratio in Au+Au at RHIC  K 0 S  Ratio 900 GeV - very good agreement between STAR (200 GeV) and ALICE (900 GeV) - very different from CDF (630/1800) and UA1 (630) for p T > 1.5 GeV - UA1(630) and CDF(630) don’t agree either … to be further investigated (different triggers, acceptance, feed-down correction ?) large Baryon/Meson ratio: parton coalescence from QGP ? |  | < 1 |y| < 0.75

23. 13/10/2010 29 th RRB J. Schukraft 23 J/  and Charm Prel. Results: - agreement between LHC experiments very good - energy/p T dependence of cross sections in line with pQCD J/  →    

24. 13/10/2010 29 th RRB J. Schukraft 24 pQCD: High p T Particle Correlations ΔΔ Trigger Associated p Tt Trigger Particle ‘away’ side ‘near’ side UE Trigger Particle: highest p T particle in event (p Tt ) Associate Particle: all the others (p Ta )

25. 25  (w.r.t. Leading Particle) Uncorrected Data Underlying Event Studies 900 GeV7 TeV ALICE Work in Progress Prel. Results: - data more “spherical” (less 2-jet like) than MC - more activity between jets (“underlying event”)

26. 13/10/2010 29 th RRB J. Schukraft 26 More on ‘Event Shapes’ Particle Correlations in 2D CMS result: unexpected ‘ridge’ in high Mult. pp somewhat similar phenomenon seen at RHIC in HI collisions ALICE acceptance smaller:  < 2 Atlas/ALICE/CMS WG established to compare results

27. 13/10/2010 29 th RRB J. Schukraft 27 Heavy Ion Preparations Trigger studies potentially large physics background (QED pair production)  SPD Trigger TOF Trigger DAQ & data transfer  Event size HI >> pp => much larger bandwidth required  specs 1.5 GB/s, reached > 2.5 GB/s  2010: can take full event rate Physics & software  Heavy Ion task force Detector  DAQ > 4 GB/s DAQ  T0 disk > 2.5 GB/s

28. ICHEP, Paris, July 2010 J. Schukraft 28 PLC 20J. Schukraft 28 Hic sunt Leones ! Summary ALICE is in good shape  most detectors perform already at or close to specifications  Concerns: SPD cooling (2012), TPC chamber stability (looks better now)  physics is in full production  heavy ions are our ‘core business’, starting in November this year  meanwhile study QCD with pp collisions  while ‘rediscovering’ the SM, we can clean up some bits here and there… (p/p, HBT R vs,  /K 0, …) Looking forward to explore the ‘terra incognita’ with HI at LHC

29. 29 We have received very strong support from the FA’s (and so we did proceed, somewhat slower than originally foreseen)