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
Spain/Cuba
Romania
Japan Brazil
South Africa
Korea
USA
China
India Croatia
Armenia
Ukraine
Mexico
JINR
Italy
Russia
~ 150 M CHF capital
France
Netherlands
Hungary
(+ ‘free’ magnet)
UK
Greece
Sweden
Poland
Norway
1200
1000
ALICE
Collaboration statistics
Slovak Rep.
Czech Rep.
TRD
800
Germany
Finland
CERN
Denmark
MoU
600
TP
400
200
0
1990
LoI
1992
1994
1996
1998
John Harris (Yale)
2000
2002
2004
QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Set-up
TOF TRD
HMPID
EMCal
ITS
PMD
Muon Arm
PHOS
John Harris (Yale)
TPC
Size: 16 x 26 meters
Weight: 10,000 tons
QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
ALICE Detectors & Acceptance
central barrel -0.9 < h < 0.9
• Df = 2p tracking, PID (TPC/ITS/ToF)
• single arm RICH (HMPID)
• single arm e.m. cal (PHOS)
• jet calorimeter (proposed EMCal)
(charged particles)
forward muon arm 2.4 < h < 4
• absorber, 3 T-m dipole magnet
10 tracking + 4 trigger chambers
multiplicity detectors -5.4 < h < 3
• including photon counting in PMD
µ arm
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 LHC
LHC 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)
•
C(q inv)
•
1 event : 5000 p
q inv (GeV/c)
John Harris (Yale)
QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
Heavy Ion Physics at the LHC
LHC 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
 shard /stotal ~
2% at SPS
50% at RHIC
98% at LHC
sbb (LHC ) ~ 100 sbb (RHIC)
• “real” jets, large pT processes
• abundance of heavy flavors
scc (LHC) ~ 10 scc (RHIC)
• probe early times, calculable  precision studies!
John Harris (Yale)
QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007
•
ALICE Physics Measurements
Hard Probes – Jet Quenching
• Jets, g , pi-zeros, leading particles to large pT
Hard Probes – Heavy Quarks
• Displaced vertices (Do  K- p+) from TPC/ITS
• Electrons in Transition Radiation Detector (TRD)
Hard Probes – Quarkonia
•
J/y, , ’ (excellent),
’’(2-3 yrs),
y’ (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 e 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)
g – 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
Approved by LHCC 9/28/06
10+1/2+1/2=11 super-modules
8 SM from US
3 SM from France, Italy
Allows Jet Measurements with ALICE
Lead-scintillator sampling calorimeter
Dh = 1.4, Df=110o
Shashlik geometry, APD photosensor
~13K towers (Dh x Df ~ 0.014 x 0.014)
Energy resolution  15%/√E + 2%
over-takes tracking above 30 GeV
po/g discrimination to pT ~ 30 GeV
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 g/p0 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
p0: pT ~ 75 GeV
inclusive g: pT ~ 45 GeV
inclusive e: pT ~ 30 GeV
John Harris (Yale)
Thanks – P.Jacobs
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)
R  (Dh ) 2  (D ) 2
John Harris (Yale)
( cone size)
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 direction
z
N. Borghini, U. Wiedemann
hep-ph/0506218
# particles with
low z increases
# particles with high z
deceases
pThadron~2 GeV
  ln 1 / z 
John Harris (Yale)
Black line = radiative E-loss
Dashed line = flat = “opaque”
What about collisional E-loss?
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 Purpose
Much to understand and significant high pT physics
at upgraded RHIC (& detectors) luminosity
at LHC
ALICE - versatile, general purpose heavy ion detector at LHC
will contribute significantly to understanding of HI physics
ALICE-USA and EMCal add significant physics to ALICE
measure and trigger on jets, photons, pi-zeros
heavy quark jet tags
triggered jets  response of medium
ALICE-USA seeks community & DOE support to
participate in ALICE
construct EMCal
extract 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
Identified particle spectra
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 (e) / contamination
pT range (PID or stat. limits) for 107 central Pb-Pb and 109 min. bias pp
For ~ 20 particle species for -1 < y < +1 and -4 < y < +2.5
p, K, p: 0.1- 0.15 to
50 GeV
Weak or strong decaying particles: to 10-15 GeV
Mid-rapidity
p
K
Pb-Pb
PID in the
relativistic rise
p
Pb-Pb
pT (GeV/c)
John Harris (Yale)
QCD Town Meeting, Rutgers University, 12 – 14 Jan 2007