DAQ@LHC Workshop ALICE Upgrade Overview Thorsten Kollegger for the ALICE Collaboration
ALICE experiment at the LHC...EPJ, arXiv:1004.3034] •Charged-particle multiplicity measurement in...
Transcript of ALICE experiment at the LHC...EPJ, arXiv:1004.3034] •Charged-particle multiplicity measurement in...
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ALICE experiment at the LHCthe activity of the LNF group
Pasquale Di Nezza
40° LNF SC meeting 24/06/10
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Alice in 1 slideWhat makes ALICE different from ATLAS, CMS and LHCb?
Experiment designed for Heavy-Ion collisionsVery robust tracking
high granularity detectors with many space points per track
very low material budget and moderate magnetic field
PID over a very large pT rangehadrons, leptons and photons
Very low pT cutoffExcellent vertexing
Prize ro be paidSlow detectorsLimited h and pT coverage
Complementary to other experiments
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The spectrometer is up and running at very high efficiency
3 papers published + 5 circulating•First pp collisions at the LHC as observed with the ALICE detector: measurement of the charged particle pseudorapidity density at sqrt(s)=900 GeV [EPJ C 65 (2010) 11] - The first LHC paper on real data•Charged-particle multiplicity measurement in pp collisions at sqrt(s)=0.9 and 2.36 TeV with ALICE at LHC [accepted by EPJ, arXiv:1004.3034]•Charged-particle multiplicity measurement in pp collisions at sqrt(s)=7 TeV with ALICE at LHC [accepted by EPJ,
arXiv:1004.3514] – The first LHC paper (arXiv) on data at 7 TeV
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The LNF Group
1. N.Bianchi (group leader)2. G.P.Capitani3. A.Casanova4. L.Cunqueiro5. P.Di Nezza6. A.Fantoni7. P.Gianotti8. S.Liuti9. A.Moregula10. V.Muccifora11. A.R.Reolon12. F.Ronchetti
A.Orlandi (tech)A.Viticchiè (tech)
12 researchers for 11.5 FTEAverage participation of 96%
1 expert on call2 shift leaders1 deputy spokesperson for calorimeter2 members of the calorimeter
Management Board1 calorimeter construction coordinator
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The activity of the LNF group
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The activity of the LNF group
Construction of thee.m. calorimeter
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The activity of the LNF group
Construction of thee.m. calorimeter
•Online monitoring•Offline codes
•High Level Trigger
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The activity of the LNF group
Jet physics
Jet reconstructionMC in QGP
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The activity of the LNF group
L
Jets with associated L
TMDs in pp
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France, Italy and USA Collaboration
– 7 US Super-Modules (SM)– 3 EU SMs (Italy and France)– Construct started in 2008– 4/10 SM installed in 2009– Complete installation in 2011
Lead-Scintillator Sampling Calorimeterh= 1.4, =100o, 20.1 X0
Shashlik Geometry, APD Photosensor12k Towers
EMCal
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Basic Unit = 4 channels
Assembling station (2 on site)
Aluminization of200k fibers (WLS)
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Quick overview on the calo performances
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Quick overview on the calo performances
0.02E0.11/σ(E)/E
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High Level Trigger for EMCal
PbPb collisions @ 8 kHz corresponds to2 kHz calo tower hit rate
HLT reduces to a 40% EMCal data occupancy
Main HLT strategy:•Reconstruction for calibration and monitoring•Event rejection using high-ET (cluster) trigger OR jet trigger
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HLT study overlapping few hundreds of pp real events to simulate PbPb
collisions
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DCal – 6 super modules
PHOS – 5 modules shown
h~0.7
From EMCal to DCalDCal, the first upgrade approved by the Alice collaboration:
extension of EMCal for jet-jet and g-jet physics
DCAL modules:same technology than EMCal
LNF contribution with tools, expertise and manpower
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Jets to access to the QGP
High-pT partons produced in hard interactions undergomultiple interactions inside the collision region priorthe hadronization … so they loose energy throughmedium induced gluon radiation the jet quenchingas a golden channel to probe the QGP
Jet →Jet’ + soft gluons + soft hadrons from UE
• Decrease of leading particle pT (energy loss)• Increase of number of low momentum particles
(radiated energy)• Increase of pT relative to jet axis (jT)
– Broadening of the jet– Out of cone radiation (decrease of jet rate)
• Increased di-jet energy imbalance and acoplanarity.)
1ln()ln(
zp
E
Borghini,Wiedemann, hep-ph/0506218
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Try to find something like this……
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Try to find something like this……
in this !
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Role of EMCal in the jet reconstruction100 GeV jet
100 GeV JetsFull simulationR=0.4
TPC+EMCal
F[rad]pp (14 TeV) 50 pb-1
PbPb (5.5 TeV) 0.5 nb-1Jets
Charged jets: 109 evts pp
107 evts cent. PbPb
Track + Calo
Charged only
Jet yield in 20 GeV bin
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Jet reconstruction
dijets @ 7 TeV
1 Jet: h-0.39 2.15 pT= 48.3 Tracks 11 2 Jet: h-0.46 5.36 pT= 31.3 Tracks 5
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Jet spectrum safely reconstructed up to 50 GeV
Jets within |h| < 0.5, Tracks within |η| < 0.9
Reconstructedglobal tracks
MC primaryparticles
MC primarycharged particles
UA1 R = 0.4 (default), 0.7 R = 0.4, 0.7 R = 0.4, 0.7
fastJET anti-kT R = 0.4, 0.7 R = 0.4, 0.7 R = 0.4, 0.7
fastJET kT R = 0.4, 0.7 R = 0.4, 0.7 R = 0.4, 0.7
fastJET SISCone R = 0.4, 0.7 R = 0.4, 0.7 R = 0.4, 0.7
CDF R = 0.4, 0.7 R = 0.4, 0.7 R = 0.4, 0.7
Deterministic Ann. R = 0.4, 0.7 R = 0.4, 0.7 R = 0.4, 0.7
Large set of jet definitions for many systematic studies/corrections
Jets @ 7 TeV
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Pileup and UE background contaminate the jet proportionally to its area
•As a consequence, we will be forced to use a small jet resolution•A neat pp reference for the jet observables is strongly needed
pT shift correction due to the hadronization is important to compare data to parton level analytical calculation
Ratio=parton/h shows hadronizationdominates at small resolution and stronger at low-intermediate jet energies
eventsunderlying
T
radiationveperturbati
T
ionhadronizat
TT pppp__
Wealth of new intriguing phenomena in the medium!
What’s new for jets in the LHC (PbPb)
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Background studies in PbPb: Fastjet method area based
Pileup and UE are distributed uniformly in h and
jetjetparton
T
jet
T AσAρp~(measured)p
r= diffuse noisesnoise fluctuations
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QPythia: a Monte Carlo for the Jet QuenchingIn collaboration with the Santiago University theory group[Armesto, Cunqueiro, Salgado]
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Distributions for different quenching
Comparison with RHIC data
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Transverse L polarization in unpolarized pp scattering
L polarization is high only at large xF.At ALICE, restricted at midrapiditieswhere xF is very small (1/pt) … unless
This opens the new channel of the TMDs(Transverse Momentum dependent Distribution
and fragmentation functions)
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Transverse L polarization in unpolarized pp scattering
L polarization is high only at large xF.At ALICE, restricted at midrapiditieswhere xF is very small (1/pt) … unless
This opens the new channel of the TMDs(Transverse Momentum dependent Distribution
and fragmentation functions)
q1f
unpolarised quarks and nucleons
q1g
longitudinally polarisedquarks and nucleons
q1h
transversely polarisedquarks and nucleons
F nxhxgxfx T15151L1Tw2Corr Sγγ)(γ)(S)(2
1)(
chiral-odd functions
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Expected magnitude of the SSA(D.Boer et al. model, PLB 659 (2008))
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pp@7TeV (EL up to 16 GeV)
L inside jets
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Conclusions
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Conclusions
Alice is running happily:
LNF group, working in:• hardware (EMCal+DCal)• online/offline software calorimetry• jet physics• QGP phenomenology• polarized physics in pp • various responsibilities
with 12 persons at 96% of FTE is fully involved in the project …
Pasquale Di Nezza
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Conclusions
Alice is running happily:
LNF group, working in:• hardware (EMCal+DCal)• online/offline software calorimetry• jet physics• QGP phenomenology• polarized physics in pp • various responsibilities
with 12 persons at 96% of FTE is fully involved in the project … with great enthusiasm!
Pasquale Di Nezza