13 Oct 2010 29 th ALICE RRB J. Schukraft 29 th ALICE RRB Collaboration News Detector Status Physics...

13 Oct 2010 29th ALICE RRB J. Schukraft

2929thth ALICE RRB ALICE RRB2929thth ALICE RRB ALICE RRB

Collaboration News

Detector Status

Physics Results

CERN-RRB-2010-073

13/10/2010 29th RRB J. Schukraft2

Collaboration News 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),


Collaboration NewsCollaboration 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


Funding..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


‘‘Upgrades’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


ALICE StatusComplete: 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


ALICE Status

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2x2x

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Installation WS Installation WS 2010/112010/11

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


Commissioning/CalibrationCommissioning/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

PHOSE/E ~ 7%

track residualsbending plane

TPC dE/dx

pions

electrons


TPC CalibrationTPC 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 DistortionsBefore Corrections

After Corrections


Material BudgetMaterial Budget Improving Detector Simulation

central part (< 450): very precisely measured (< 5%) forward part: improved description in simulation (using design drawings/installation photo’s)

Material in simulation

SSD

SDD

SPD

FMD multiplicityNot fully corrected


Operational IssuesOperational 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 H2O (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


Physics & Data Physics & Data TakingTakingPhysics with pp

collect ‘comparison data’ for heavy ion program many signals measured ‘relative’ to pprequires ~ 109 MinBias events+few 10 pb-1 rare

focus on MB; reduced L, displaced beamsnow and 2011: increased L for rare processes

comprehensive study of MB@LHCtuning of Monte Carlo (background to BSM)

soft & semi-hard QCDvery complementary to other LHC exptsaddress 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 ~ 107 MinBias events (1-3 b-1)


Some Performance Some Performance PlotsPlots

J/ → e+e- |y| < 0.9

J/ → , y = 2.5 - 4

→ (PHOS + TPC)

→

- hard to measure J/ with our current low L (also 1st year Pb Lumi will be very low -> priority on MB in pp)

- ‘proof of detector performance’ higher L later this year and next


Charm at 7 TeV Charm at 7 TeV (ICHEP)(ICHEP)

D0→ D0→

D+→

D*→ D Ds

+→ Φπ+→

Impact Parameter Resolution vs pT

80 m @ 1 GeV


(Anti) Nuclei(Anti) Nuclei

Distance of track to collision vertex

TPC dE/dx

7 TeV pp ≈5-6%


Data Taking Data Taking SummarySummary

>750 Million interactions

> 50 MMuon triggers

Integrated data taking efficiency ~ 80%since Sept increasing to > 90%

> 20 Mhigh Multiplicity

Operation:shift crew reduced from > 30 to 6 people

+ ~ 30 ‘on call’ experts (24h 7/7)


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Offline ProcessingOffline 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 Processing1.3K runs 321K files 756 TB

Resource Usage

• 1st 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%


ResultResultss

Final Results Nch multiplicity & distributions

900 GeV: EPJC: Vol. 65 (2010) 111900 GeV, 2.36 TeV: EPJC: Vol. 68 (2010) 897 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 (D0,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 (K0,,,,

Global eventproperties

Comparison Data

clarifies QCD issue


Kaon pT distributions

stable & decays

K →

K0S →

Identified ParticlesIdentified Particles

Identified Particle pT

K p

ITS dE/dx

TPC dE/dx TOF


Stable: Stable: , K, p at 900 , K, p at 900 GeVGeV

Prel. Results:

- very large K/ ratio at high pT

- not reproduced by event generators


Decays: KDecays: K00SS at 900 at 900 GeV GeV **

Prel. Results:

- MC well below Data

- more so at high pT

- more so for- ~ ok (at least some MC)

K0S → → p

→ K K→

* 2009 Data (~300 k events)


/K0S Ratio in Au+Au at RHIC

KK00SSRatio 900 Ratio 900

GeVGeV

- very good agreement between STAR (200 GeV) and ALICE (900 GeV)

- very different from CDF (630/1800) and UA1 (630) for pT > 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

https://twiki.cern.ch/twiki/pub/ALICE/PWG2SpectraTopicalBaryonMesonRatio/UA1ratioLambdaK0s.jpeg


J/J/and and CharmCharm

Prel. Results:

- agreement between LHC experiments very good

- energy/pT dependence of cross sections in line with pQCD

J/ →


pQCD: High ppQCD: High pTT Particle Correlations Particle Correlations

Δ

Trigger

AssociatedpTt

Trigger Particle

‘away’ side

‘near’ side

UE

Trigger Particle: highest pT particle in event (pTt)

Associate Particle: all the others (pTa)

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(w.r.t. Leading Particle) (w.r.t. Leading Particle)

Uncorrected Data

Underlying Event StudiesUnderlying Event Studies

900 GeV 7 TeV

ALICE Work in Progress

Prel. Results:

- data more “spherical” (less 2-jet like) than MC

- more activity between jets (“underlying event”)


More on ‘Event Shapes’More on ‘Event Shapes’ Particle Correlations in 2D

CMS result: unexpected ‘ridge’ in high Mult. ppsomewhat similar phenomenon seen at RHIC in HI collisions

ALICE acceptance smaller: < 2Atlas/ALICE/CMS WG established

to compare results


Heavy Ion Heavy Ion PreparationsPreparations 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

ICHEP, Paris, July 2010 J. Schukraft28 PLC 20J. Schukraft28Hic sunt Leones !

SummarSummaryy

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 <kT>, /K0, …)

Looking forward to explore the ‘terra incognita’ with HI at LHC

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We have received very strong supportfrom the FA’s

(and so we did proceed, somewhat slower than originally foreseen)

13 Oct 2010 29 th ALICE RRB J. Schukraft 29 th ALICE RRB Collaboration News Detector Status Physics...

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Transcript of 13 Oct 2010 29 th ALICE RRB J. Schukraft 29 th ALICE RRB Collaboration News Detector Status Physics...