John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE-USA
LHC
Alice
Dedicated “general purpose”Heavy Ion experiment at LHC
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Collaboration
~ 1000 Members
(63% - CERN States)
~ 30 Countries
~ 100 Institutes
~ 150 M CHF capital
(+ ‘free’ magnet)
0
200
400
600
800
1000
1200
1990 1992 1994 1996 1998 2000 2002 2004
ALICE Collaboration statistics
LoI
MoU
TP
TRD
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Set-upHMPID
Muon Arm
TRD
PHOS
PMD
ITS
TOF
TPCSize: 16 x 26 meters
Weight: 10,000 tons
EMCal
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Detectors & Acceptance
(charged particles)
µ arm
central barrel -0.9 < < 0.9• = 2 tracking, PID (TPC/ITS/ToF)• single arm RICH (HMPID)• single arm e.m. cal (PHOS)• jet calorimeter (proposed EMCal)
forward muon arm 2.4 < < 4• absorber, 3 T-m dipole magnet10 tracking + 4 trigger chambers
multiplicity detectors -5.4 < < 3• including photon counting in PMD
trigger & timing detectors• 6 Zero Degree Calorimeters• T0: ring of quartz window PMT's• V0: ring of scint. Paddles
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Heavy Ion Physics at the LHCLHC Heavy Ions –
• guided by pQCD predictions • expectations (detector simulations) based on RHIC extrapolations and theory• lesson from RHIC – guided by theory + versatility + “expect the unexpected”
Soft Physics at LHC – • smooth extrapolation from SPS RHIC LHC?• expansion will be different (v2, HBT, Tchem & Tkin,
strange/charm particles & resonances)
1 event : 5000
C(q
inv)
q inv (GeV/c)
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Heavy Ion Physics at the LHCLHC Heavy Ions –
• guided by pQCD predictions • expectations (detector simulations) based on RHIC extrapolations and theory• lesson from RHIC – “expect the unexpected”
Soft Physics at LHC – • smooth extrapolation from SPS RHIC LHC?• expansion will be different (v2, HBT, Tchem & Tkin,
strange/charm particles & resonances)
Hard Probes at LHC – • significant increase in hard cross sections
hard /total~ 2% at SPS
50% at RHIC
98% at LHC• “real” jets, large pT processes
• abundance of heavy flavors• probe early times, calculable precision studies!
bb (LHC ) ~ 100 bb (RHIC)
cc (LHC) ~ 10 cc (RHIC)
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Physics Measurements
Hard Probes – Jet Quenching• Jets, pi-zeros, leading particles to large pT
Hard Probes – Heavy Quarks• Displaced vertices (Do K- +) from TPC/ITS• Electrons in Transition Radiation Detector (TRD)
Hard Probes – Quarkonia• J/, , ’ (excellent), ’’(2-3 yrs), ’ (NO WAY…)
Soft Probes – “ala RHIC” • Expansion dynamics different from RHIC due to timescales, densities• All soft physics measurements as at RHIC so far (+ extended PID)• Day 1 physics +
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE-USA
ALICE-USA Collaboration
12 DOE-supported research institutions:
Creighton , Houston, Kent State, LBNL, LLNL, Michigan State,
Oak Ridge, Purdue, Tennessee, Texas, Wayne State, and Yale
ALICE-USA Primary Focus
• Investigate medium modification of partonic energy loss – “jet quenching”
• Investigate response of medium to large energy depositions
ALICE-USA Equip. Proposal to DOE for Major Fraction of ALICE EMCal
• Construct 8 of 11 super-modules of EMCal for ALICE
Italy and France proposing to construct 3
• CERN LHC Committee approved EMCal for installation in ALICE
• Passed CDs-0,1 Reviews of DOE
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Scientific Focus of ALICE-USA Primary Scientific Goal
“Investigate QCD matter and measure its properties at high at the LHC”
Primary Focus – Utilize Initial Hard Parton Scattering
• High energy jets, photons and heavy flavors requires EMCal and triggering
Exploit large kinematic range of jets at LHC
Measure jet structure & medium-induced jet modification
Investigate energy loss mechanism with
quark-tagged jets (heavy flavor decays)
gluon jets (light hadron leading)
– jet coincidences
• Low energy particles correlated with trigger or quenched jet
requires ALICE acceptance, robust tracking, & PID to low/high
pT
Investigate energy propagation in medium to determine medium properties
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE EMCal
10+1/2+1/2=11 super-modules8 SM from US3 SM from France, Italy
Lead-scintillator sampling calorimeter = 1.4, =110o
Shashlik geometry, APD photosensor ~13K towers ( x ~ 0.014 x 0.014)
Energy resolution 15%/√E + 2%
over-takes tracking above 30 GeV
o/ discrimination to pT ~ 30 GeV
Approved by LHCC 9/28/06
Allows Jet Measurements with ALICE
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Capabilities of ALICE Extended by EMCal
EMCal improves detector capabilities:
- Fast trigger ~10 -100 enhancement of jets
- Improves jet reconstruction (plus TPC)
- Good discrimination
increases coverage
- Good electron/hadron discrimination
EMCal extends the physics of ALICE:
104 / year in minbias Pb+Pb:
inclusive jets: ET ~ 200 GeV
dijets: ET ~ 170 GeV
: pT ~ 75 GeV
inclusive : pT ~ 45 GeV
inclusive e: pT ~ 30 GeVThanks – P.Jacobs
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Performance for Jets
ET = 100 GeV, R = 0.4
EM (TPC+EMCal)
(TPC)
(TPC – like RHIC)
size) cone ( )()(R 22
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Medium Modification of Fragmentation from Jets
Fragmentation along jet axis: z = phadron / p parton
Introduce = ln(Ejet / phadron) ~ ln (1/z):
jet directionz
N. Borghini, U. Wiedemannhep-ph/0506218
# particles with low z increases
# particles with high z deceases
z/1ln
pThadron~2 GeV
Black line = radiative E-loss
Dashed line = flat = “opaque”
What about collisional E-loss?
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE-USA Manpower
ALICE-USA Collaboration Manpower Estimates
from 12 DOE-supported research institutions:
Creighton , Houston, Kent State, LBNL, LLNL, Michigan State, Oak Ridge,
Purdue, Tennessee, Texas, Wayne State, and Yale
FTEs estimate for:EMCal detector support, trigger, computing, simulations & analysis, and papers
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Summary and PurposeMuch to understand and significant high pT physics
at upgraded RHIC (& detectors) luminosity at LHC
ALICE - versatile, general purpose heavy ion detector at LHCwill contribute significantly to understanding of HI physics
ALICE-USA and EMCal add significant physics to ALICEmeasure and trigger on jets, photons, pi-zerosheavy quark jet tagstriggered jets response of medium
ALICE-USA seeks community & DOE support to participate in ALICEconstruct EMCalextract exciting, fundamental physics
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Back-up Slides
John Harris (Yale) QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Particle reconstruction and identification capabilities: unique to ALICE Global tracking (ITS-TPC-TRD) + dE/dx (low pT + relativ. rise), TOF, HMPID, PHOS, …
Invariant mass, topological reconstruction Acceptance / efficiency / reconstruction rate () / contamination pT range (PID or stat. limits) for 107 central Pb-Pb and 109 min. bias pp
Identified particle spectra
Pb-Pb
Mid-rapidityPID in the relativistic rise
p
K
Pb-Pb
pT (GeV/c)
For ~ 20 particle species for -1 < y < +1 and -4 < y < +2.5
, K, p: 0.1- 0.15 to 50 GeV Weak or strong decaying particles: to 10-15 GeV
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