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 1 Strangeness in Quark Matter 2008
Jan 11, 2016
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