byungsik hong (korea university) for the collaboration strangeness in quark matter 2008 tsinghua...
TRANSCRIPT
Byungsik Hong (Korea University)
for the Collaboration
Strangeness in Quark Matter 2008
Tsinghua Univ., Beijing, China
Exploring High-Density QCD Matter
with CMS/LHC
October 6-10, 2008 1Strangeness in Quark Matter 2008
CMS Heavy-Ion Program
October 6-10, 2008
D. d’Enterria et al. (eds.), CERN-LHCC-2007-009, J. Phys. G 34, 2307-2455 (2007)
Heavy-Ion Institutions
Adana Athens Auckland Budapest-Eötvös L. CERN Budapest-KFKIU.I. Chicago ChonbukColorado DavisDemokritos Ioannina Iowa KansasKorea Univ. Lisbon Los Alamos LyonMaryland MITMinnesota Moscow Mumbai U. of Seoul Vanderbilt Zagreb
~25 Institutions~100 Collaborators
2Strangeness in Quark Matter 2008
Contents
1. Introduction– Physics motivation and the CMS detector
2. CMS Capability for Heavy-Ion Physics– Soft Probes
• Hydrodynamics, QCD EoS, Medium viscosity, ...• dNch/dη, Low pT spectra, Elliptic flow, …
– Hard Probes• Color charge density, Transport coefficient, QCD εc & Tc ,
Tomography, …• High pT spectra, jets, or Z-jet correlations,
Quarkonia, …– UPC
• Photoproduction of →l+l-
3. Summary
October 6-10, 2008 3Strangeness in Quark Matter 2008
October 6-10, 2008 4Strangeness in Quark Matter 2008
LHC: New Energy Frontier
October 6-10, 2008
AGS SPS RHIC LHC
sNN (GeV) 5 20 200 5500
Increasing Factor x4 x10 x28
y range 1.6 3.0 5.3 8.6
LHC energies are far exceeding the range of previous heavy-ion accelerators- Extended kinematic reach for pp, pA, and AA collisions
- New properties of the initial state and saturation at mid-rapidity
- A hotter, denser, and longer lived partonic matter
- Increased cross sections and availability of new hard probes
New energy regime will open a new window on hot and dense QCD matter physics: another large energy jump!
5Strangeness in Quark Matter 2008
Energy Density at LHC
October 6-10, 2008
32
0
GeV/fm 10)(
1
d
dE
RT
Bjorken
fm/c) 004.0(~ /2fm/c 1~with 0 R
6Strangeness in Quark Matter 2008
Production Rate at LHC
October 6-10, 2008 7Strangeness in Quark Matter 2008
October 6-10, 2008
CASTORCASTOR
T2T2
Collar Collar shieldingshielding
Forward DetectorsForward Detectors
(5.2 < < 6.5)
TOTEMTOTEM
ZDCZDC
(5.3 < < 6.7)
(z = 140 m)
BeamsBeams
EMEM
HADHADMUON BARRELDrift Tubes & RPCsm≈50 MeV at 10 GeV/c2
SUPERCONDUCTINGCOILS
IRON YOKE
TRACKERSi Pixels & StripsΔp/p ≈1-2% Occupancy < 2% for central Pb+Pb
Total weight : 12,500 tOverall diameter : 15 mOverall length : 21.6 mMagnetic field : 4 Tesla
HCALCu-ScintillatorSampling
ECALPbWO4 Crystals
MUON ENDCAPSCathode Strip Chambers & Resistive Plate Chambers (RPCs)
CMS Detector
8Strangeness in Quark Matter 2008
CMS Acceptance
October 6-10, 2008
HCAL (Barrel+Endcap+Forward)
Large Range of Hermetic Coverage
Silicon and μ Tracker 2.4
ECAL 3.0
HCAL 5.2
CASTOR 5.2 6.5
ZDC 8.3 for neutrals
x~ⅹ(1/40) of RHIC (<10-4 measurable)Qs
2 ~ⅹ3 of RHIC 9Strangeness in Quark Matter 2008
View of Barrel
October 6-10, 2008 10Strangeness in Quark Matter 2008
Endcap Disks
October 6-10, 2008 11Strangeness in Quark Matter 2008
October 6-10, 2008
Soft Probes of QCD Matter in CMS
12Strangeness in Quark Matter 2008
Charged Particle Multiplicity
October 6-10, 2008
Total 66M Si PixelsOccupancy < 2% at dNch
/dη=5000
Estimation of the Gluon Density Does the Gluon Saturation Exist?Color Glass Condensate (CGC)
Pseudorapidity
Mult
iplic
ity d
Nch
/d
C. Smith, CMS-NOTE-2003-015
13Strangeness in Quark Matter 2008
Hadron Spectra at Low pT
October 6-10, 2008
Rel. pT Resolution=2-3%
Tracking: Pixel-Triplet Algotithm
Efficiency Pixel only Fake Rate<10%
Acceptance
F. Sikler, CMS-NOTE-2006-100 & 101
14Strangeness in Quark Matter 2008
Hadron Spectra at Low pT
October 6-10, 2008
PID by Using the Gaussian Unfolding Method for dE/dx
Hadron ChemistryExpansion DynamicsEquation-of-StateStrangeness Production
Pix
els
+S
trip
s
pT [GeV/c]
,...,,,,,,0 KKS
F. Sikler, CMS-NOTE-2006-100 & 101
15Strangeness in Quark Matter 2008
Elliptic Flow
October 6-10, 2008
I. Lohkin et al., CMS-NOTE-2003-019
HydrodynamicsEquation-of-StateViscosity of Fluid
G. Eyyubova et al., CMS-NOTE-2007-004
Non-flow systematic uncertainties not included
Reaction Plane Resolution
16Strangeness in Quark Matter 2008
October 6-10, 2008
Hard Probes of QCD Matter in CMS
17Strangeness in Quark Matter 2008
High-Level Trigger
October 6-10, 2008
M. Ballitjin, C. Loizides, G. Roland, CMS-NOTE-2006-099Level 1 (Muon Chambers+Calorimeters)
High-Level Triggers (high ET-jet, γ, e, μ)• 12k CPU 1.8 GHz ~ 50 Tflops ( 2 RCF)ⅹ ⅹ• Run “offline algorithm” on every Pb+Pb event• Significantly enhanced statistics for hard processes (see the right figure)
High-Level Trigger Pb+Pb p+p
Input Event Rate 3 kHz (8 kHz peak) 100 kHz
Output Bandwidth 225 MByte/sec 225 MByte/sec
Output Rate 10 – 100 Hz 150 Hz
Rejection 97-99.7% 99.85%
Level 1 Pb+Pb p+p
Collision Rate 3 kHz (8 kHz peak) 1 GHz
Event Rate 3 kHz (8 kHz peak) 32 MHz
Output Bandwidth 100 GByte/sec 100 GByte/sec
Rejection None 99.7%
ET reach x2
jets
Pb+Pb at 5.5 TeV
design luminosity
18Strangeness in Quark Matter 2008
Particle Spectra at High pT
October 6-10, 2008M
om
entu
mre
solu
tion
[%]
Perc
enta
ge [
%]
Medium Density
Transport Coefficient
Charged particle spectra up to pT ~300 GeV/c(High ET HLT)
C. Roland, CMS-NOTE-2006-001 & 110
19Strangeness in Quark Matter 2008
Full Jet Reconstruction
October 6-10, 2008
Iterative cone(R=0.5)+Background subtraction
High efficiency and purity for ET>50 GeV
Good energy resolution for ET>100 GeV
I. Vardanyan et al., CMS-NOTE-2006-050
Jet spectra up to ET ~500 GeV
Jet Quenching Effect by using True Jets
Pb+Pb (0.5 nb-1: 1 year of running)
Min. Bias HLT
100 GeV jet ina Pb+Pb event,after background subtraction
20Strangeness in Quark Matter 2008
Photon-Tagged Jets
October 6-10, 2008
* (or Z0) →μ+μ- is being also
studied
associated
hadrons
jet
g (q)g (q)
g (q)
Photons-Tagging parton energy-Sophisticated isolation/shape cut technique was developed
(S/B was improved by about 15)
-ET(>100 (or 70) GeV
C. Loizides, QM08
How is the energy loss distributed in the jet fragmentation cone?
21Strangeness in Quark Matter 2008
Photon-Tagged Jets
October 6-10, 2008
Reconstructed FF agrees with the MC FF
Require the back-to-back -jet correlation by (,jet) > 3 rad.
Depletion at high pT
Enhancement at low pT
22Strangeness in Quark Matter 2008
Heavy Flavor (J/)
October 6-10, 2008
S/B = 1.2J/ψ=35 MeV/c2
BARREL+Endcaps
dNch /dη|η=0 =2500
pT (G
eV
/c)
The best +- mass resolution at LHC
Pb+Pb (0.5 nb-
1)
NJ/~1.8×105
O. Kodolova and M. Bedjidian, CMS-NOTE-2006-116
• J/ψ Suppression: RHIC≈SPS (!)
• Regeneration↑≈ Screening↓(?)
• J/ψ may survive up to 2 TC (?)
• Question at LHC: Further suppression or Enhancement?
The J/ spectra beyond40 GeV/cusing HLT
23Strangeness in Quark Matter 2008
Heavy Flavor ()
October 6-10, 2008
dNch /dη|η=0 =2500
pT (
GeV
/c)
- The spectra beyond 40 GeV/c using HLT
N~2.5 ⅹ104
σm=54 MeV/c2 for BARREL → σm=90 MeV/c2 for BARREL+ENDCAP (The best +- mass resolution at LHC)
O. Kodolova and M. Bedjidian, CMS-NOTE-2006-116
24Strangeness in Quark Matter 2008
Production in UPC
October 6-10, 2008
Strong E&M fields due to the coherent action of 82 protons (max~80 GeV)
)HERA(3
TeV/u 1
)HI:LHC(max
p
Pb
s
s
)LEP(
GeV 160
)HI:LHC(max
s
s
~500 ’s/0.5nb-1 Unexplored xG(x,Q2) region
25Strangeness in Quark Matter 2008
Summary
1. The CMS detector is versatile not only for pp, but also for heavy-ion collisions.
2. The CMS high-resolution trackers, calorimeters, and muon chambers cover almost 4 phase space.
3. The CMS detector can measure various hard probes with the best resolution at the LHC.
4. The CMS detector can also measure soft hadrons for pT≥100 MeV/c with excellent particle identification.
October 6-10, 2008 26Strangeness in Quark Matter 2008