Heavy-Ion Program in CMS at tHeavy-Ion Program in CMS at the Large Hadron Colliderhe Large Hadron Collider
Byungsik Hong
Korea University
OutlineOutline1. Most Important results from RHIC
2. LHC & CMS
3. Heavy-ion program at LHC
4. Korean contributions to CMS so far
5. Preparation of CMS heavy-ion program in Korea
05-13-2006 KIAS Workshop on LHC 2
Motivation of HI CollisionsMotivation of HI CollisionsInvestigating the QCD prediction of a deconfined (& chiral symmetry restored) high-energy-density phase of nuclear matter
QGP is thought to have existed ten millionths of second after the Big Bang; creating the primordial matter of universe in the laboratory, Little Bang.
High-energy nuclear collisions will compress and heat the heavy nuclei so much that their individual protons and neutrons overlap and lots of pions arise, creating the Quark-Gluon Plasma (QGP)
05-13-2006 KIAS Workshop on LHC 3
Lattice QCDLattice QCDPhase transition is expected in a strongly interacting matter, but not so close to the Stefan-Boltzmann limit.
05-13-2006 KIAS Workshop on LHC 4
Relativistic Heavy-Ion Relativistic Heavy-Ion MachinesMachines
Acceleratorc.m. Energy
(GeV)Status
SIS 18
(GSI, Germany)
2A
(A=mass number)
Running
AGS
(BNL, USA)5A Finished
SIS 300
(GSI, Germany)8A
Plan to run from ~2014
SPS
(CERN, Switzerland)20A Finish soon
RHIC
(BNL, USA)200A
Has been run since 2000
LHC
(CERN, Switzerland)5500A
Plan to run from ~2007
05-13-2006 KIAS Workshop on LHC 5
Phases of Nuclear MatterPhases of Nuclear Matter
SIS300
05-13-2006 KIAS Workshop on LHC 6
Brookhaven National Lab.Brookhaven National Lab. in New Yorkin New York
Circumference: 3.83 km First collision: 2000 100A GeV Au+Au(2X1026/cm2/s) 250 GeV p+p(2X1032/cm2/s)
Relativistic Heavy Ion ColliderRelativistic Heavy Ion Collider
05-13-2006 KIAS Workshop on LHC 7
QGP ProbesQGP Probes
1. Expectation– quarks and quarkonium states may respond differen
tly to a plasma compared to ordinary nuclear matter
2. Hard Probes– Formed in initial collisions with high Q2
– Calculable in pQCD given • Parton structure function• Hard scattering rate• Fragmentation function q q
Hadron jet
Hadronjet
05-13-2006 KIAS Workshop on LHC 8
Partonic Energy Loss in QGPPartonic Energy Loss in QGP
Partons are expected to loose energy via gluon radiation in traversing a QGP(jet quenching)
Hadrons above pT > 2 GeV expected to be from jet fragmentationLook for a suppression of leading hadrons in that pT region
05-13-2006 KIAS Workshop on LHC 9
SuppressionSuppression
• strong suppression in π0:– decreasing with pT
– factor 6 at pT > 6 GeV/c
• similar suppression in charged hadrons– RAA slightly higher at
intermediate pT due to protons
• discrepancies in charged RAA between experiments– Glauber calculations?
– NN-reference?• better consistency
between STAR and PHENIX for central/peripheral!
PHENIX, PRL 91, 072301 (2003)
05-13-2006 KIAS Workshop on LHC 10
Initial vs. Final State EffectInitial vs. Final State EffectInitial state: gluon saturation?
CGC?
How to discriminate? Turn off final state d+Au collisions
Final state: parton energy loss?
05-13-2006 KIAS Workshop on LHC 11
Centrality DependenceCentrality Dependence
1. Dramatically different and opposite centrality evolution of Au+Au experiment from d+Au control one.
2. Jet Suppression is clearly a final state effect.
Au + Au Experiment d + Au Control Experiment
Preliminary DataFinal Data
05-13-2006 KIAS Workshop on LHC 12
Jet Jet CorrelatioCorrelationn
triggerPhys Rev Lett 90, 082302
05-13-2006 KIAS Workshop on LHC 13
Away-Side Jet Correlation at Low Away-Side Jet Correlation at Low pptt
1σ syst
2σ syst
PHENIX Preliminary
05-13-2006 KIAS Workshop on LHC 14
InterpretationInterpretation
Near SideFar Side
PHENIX Preliminary
Discovery of the color shockwave?Discovery of the color shockwave?
05-13-2006 KIAS Workshop on LHC 15
Elliptic FlowElliptic Flow
x
z
y
...))2cos(v2)cos(v21( 21
3
dyddpp
Nd
tt
Rmeas
tim
e
reaction plane
transverse plane(at midrapidity)
v2<0 v2 >0 elliptic flow
RN=(1+ v2)/(1-v2)
v1<0 v1 >0sideward flow
px = v1 pt
05-13-2006 KIAS Workshop on LHC 16
Anisotropic FlowAnisotropic Flowvv11, v, v22, v, v44, …, …
Sp
ect
ato
rs
Reaction plane
~-3 ~3~0
v2 = 15%v2 = 15%, v4=4%
v2 = 7%v2 = 7%, v1=+7%
v2 = 7%v2 = 7%, v1=-7%Isotropic emission
Sp
ecta
tors
X
Y
1
In-planeOut
-of-
plan
e
1.5
0.5
η∼0η∼3η∼-3
x
z
05-13-2006 KIAS Workshop on LHC 17
Directed Flow vDirected Flow v11
STAR, PRL92, 062301 (2004) NA49, PRC69, 034903 (2003)M. Belt-Tonjes for PHOBOS (QM04)H. Masui for PHENIX (QM04)
1. Consistent among RHIC Expts.2. Shape in forward rapidity agree with
low energy data by NA493. Elongated shape near midrapidity
05-13-2006 KIAS Workshop on LHC 18
vv22 vs Rapidity vs Rapidity
M.B. Tonjes for PHOBOS (QM04)
v2 is positive:v1 and v2 are in the same plane
STAR
05-13-2006 KIAS Workshop on LHC 19
vv22 vs Transverse Momentum vs Transverse Momentum
Quark Recombination or Coalescence?Quark Recombination or Coalescence?
05-13-2006 KIAS Workshop on LHC 20
Recombination ModelRecombination ModelB. Hong, C.-R. Ji, and D.-P. Min, Phys. Rev. C 73, 054901 (2006)
05-13-2006 KIAS Workshop on LHC 21
Summary of Present RHIC Summary of Present RHIC ResultsResults1. RHIC collisions produce more particles and energy th
an ever produced.2. Fireball is close to the condition for early universe in
energy density estimate and antiproton/proton ratio (> 0.6).
3. Jet quenching is observed with high pt single hadrons and jet correlations → rapid formation of QGP
4. Hot and dense matter behaves collectively and consistent with the quark recombination model → formation of the strongly interacting liquidlike QGP with the viscosity near zero
5. Spectra for electron and muons, and their implications for charm production.
05-13-2006 KIAS Workshop on LHC 22
Future of HI research Future of HI research
1. Establish that the QGP is formed via leptons.
2. Explore the energy and system size dependence for the threshold effect.
3. Spin structure function of partons, especially gluons by polarized proton collisions
4. Future Project– LHC heavy-ion collision (CMS in particular)– CBM/SIS200/GSI heavy-ion collisions for the
highest baryon density nuclear matter
RH
IC
05-13-2006 KIAS Workshop on LHC 23
What is LHC?What is LHC?1. Run p-p collisions f
rom 2007 - Find Higgs and Supersymmetry, etc.
2. Run Pb-Pb and other ion collisions from about 2008 - Find QGP and study the detailed properties.
05-13-2006 KIAS Workshop on LHC 24
Cosmic TimelineCosmic TimelineTaken from Scientific American (May 06)Taken from Scientific American (May 06)
05-13-2006 KIAS Workshop on LHC 25
CMS (Compact Muon Solenoid)CMS (Compact Muon Solenoid)
05-13-2006 KIAS Workshop on LHC 26
Tracking with Tracking with heavy-ion eventsheavy-ion events
pT/
p T (%
) |η| < 0.7
FakesE
ffic
ienc
y (%
)
dN/dy
pT > 1GeV
pT > 3GeV
pT (GeV)
(c
m)
Impact parameter resolutionImpact parameter resolution
• z
• r
Fakes
Eff
icie
ncy
(%)
pT (GeV)
05-13-2006 KIAS Workshop on LHC 27
TOTEM T2
BCM Sensor CarriageScintillators atz=10.5m
IP
TOTEM T1
BCM Sensors
ZDC @ 140 m
CASTOR
Lumi monitor
Hermetic calorimetry up to ||<7 plus zero degree neutral energy. T1 and T2 are multiplicity detectors.Physics: Centrality, Low-x, Limiting fragmentation, strangelets, DCC, etc.
Forward DetectorsForward Detectors
05-13-2006 KIAS Workshop on LHC 28
ET for 3<||<5
Collision GeometryCollision GeometryE
T (G
eV)
b (fm)
Assume = 0.1 radians
x
z
y
05-13-2006 KIAS Workshop on LHC 29
Expected Expected NNchch ?
HIJING vs
ion extrapolat RHICby
000,7200,1/ dydNch
05-13-2006 KIAS Workshop on LHC 30
Kinematic Range by LHCKinematic Range by LHC
J/ψ
Z0
BRAHMSBRAHMSP
HE
NIX
PH
EN
IX
LHCLHCε ~ 50 GeV/fm3
Low xHigh M High Pt
JetsQuarkoniaPhotonsZ0, etc.
by
05-13-2006 KIAS Workshop on LHC 31
Abundant QuarkoniaAbundant Quarkonia
J/ψ
Large production cross section→ should be enough to observe different melting points
of 3 states.
05-13-2006 KIAS Workshop on LHC 32
Quarkonia and QGP Quarkonia and QGP Ref) H. Satz, hep-ph/0512217
larger
smaller
05-13-2006 KIAS Workshop on LHC 33
Quarkonia in CMSQuarkonia in CMS
J/ family
Expect ~24k J/ψ and ~ 18/5/3 k ,’,’’
for one month with L=1027cm-2s-1
and 50% efficiency
σM = 50 MeV
Coverage in central rapidity region
- -
+ +
05-13-2006 KIAS Workshop on LHC 34
Abundant JetAbundant JetLarge jet cross section
•Full jet reconstruction: jet-jet, jet-, jet-Z0 correlations
•Study in medium modifications
05-13-2006 KIAS Workshop on LHC 35
Fragmentation of 100 GeV Jets Fragmentation of 100 GeV Jets
Precision tracking out to high
momenta will give detailed
information on modification of the jet by the medium
axis
pT jet
pT relative to thrust axis
Momentum fraction z along thrust axis
05-13-2006 KIAS Workshop on LHC 36
Forward Region of CMS
Korea
Italy
Korea in CMSKorea in CMS Total Area of Endcap RPC ~1,400 m2
05-13-2006 KIAS Workshop on LHC 37
Resistive Plate ChamberResistive Plate Chamber
Final Gas mixture used in all tests95.5% Freon 3.5% Isobutane 0.3% SF6 + RH 50%
GapMechanics
05-13-2006 KIAS Workshop on LHC 38
History of the Korean RPCHistory of the Korean RPC1. Fundamental studies to develop the Endcap RPCs (1997 - )
1) CERN beam test by using high intensity muon beam and 20 Ci 137Cs2) Cosmic muon tests (Korea Univ.) 3) Study of RPC pulses and simulations 4) Long term aging study for linseed oiled RPC
2. Design of double gap RPCs for the Endcap Region (2000 – 2003)1) Chamber designs 2) Services for HV, LV, gas, electronics on the chamber level
3. Detector manufacturing facilities (2000 – 2003) 1) Gap and chamber production facilities 2) Gaps and chamber testing facilities for the quality controls
4. Mass production of the Endcap RPC (2004 - )
05-13-2006 KIAS Workshop on LHC 39
Endcap RPCEndcap RPC1. Function : L1 muon triggers 2 wings (RE+, RE-)
4 stations (RE1, RE2, RE3, RE4)
Pseudo rapidity covering:
0.9 < η < 2.1(1.6)
η segmentations : 10 (6)
2. Total # of RPCs : 756 (432)
Total # of FEBs : 2,268 (1,296)
Total # of channels : 85,248 (41,472)
3. By September 2006,
the gap production in 0.9 < η < 1.6
will be completed for the
first operation of the CMS detector.
05-13-2006 KIAS Workshop on LHC 40
Korean Endcap RPCKorean Endcap RPC
Characteristics
CMS Requiremen
tsTest Results
Time Resolution < 3 nsec < 1.5 nsec
Efficiency > 95 % > 95 %
Rate Capability > 1 kHz/cm2 > 1 kHz/cm2
Noise Rate < 15 Hz/cm2 < 10 Hz/cm2
Plateau Region > 300 V > 400 V
Summary of the Performance
05-13-2006 KIAS Workshop on LHC 41
18 RE1/2s have been installed on CMS in last 2 weeks
A RE1/2 is mated to CSC before installation
Installation of the very 1st RE1/2+CSC module
1st RE1/2 installed on CMS
CSC
RE1/2
05-13-2006 KIAS Workshop on LHC 42
05-13-2006 KIAS Workshop on LHC 43
Participation of the Korean Participation of the Korean Heavy-Ion Group in CMSHeavy-Ion Group in CMS
1. Korea University (B. Hong and K.S. Sim)– Important role in the endcap RPC production since 1997– Preparing the computing facility for MC simulation and d
ata analysis
2. Konkuk University (J.T. Rhee)– Important role in the endcap RPC production since 1997
3. City University of Seoul (I.C. Park)– Will use existing computing facility for MC simulation and
data analysis
4. Pusan National University (I.K. Yoo)5. Yonsei University (J.H. Kang)6.6. All major HI institutions in Korea will participatAll major HI institutions in Korea will participat
e in the CMS Heavy-Ion program.e in the CMS Heavy-Ion program.
CM
S 참
여를
결정
한 순
서
05-13-2006 KIAS Workshop on LHC 44
ConclusionsConclusions
1. RHIC has produced a lot of exciting new results on the quark-gluon matter in extreme conditions.
2. We look forward to seeing even more exciting results in heavy-ion collisions at LHC.
– New energy frontier: √s ~1.2 PeV for a Pb-Pb collision event
3. Korean Heavy-Ion group has contributed a lot already on the construction of the CMS endcap RPC system.
4. Korean Heavy-Ion group is preparing the computing farm for the CMS MC generation and data analysis.
5. All major institutions will participate in the CMS heavy-ion program.
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