exploring the qcd phase diagram at high baryon densities: from sps to fair
DESCRIPTION
Exploring the QCD Phase Diagram at High Baryon Densities: From SPS to FAIR. Claudia Höhne, GSI Darmstadt. QCD phase diagram results from SPS and RHIC CBMphysics topics and observables feasibility studies and R&D. QCD phase diagram at high baryon densities. - PowerPoint PPT PresentationTRANSCRIPT
Exploring the QCD Phase Diagram at High Baryon Densities: From SPS to FAIR
Claudia Höhne, GSI Darmstadt
• QCD phase diagram
• results from SPS and RHIC
• CBM physics topics and observables
feasibility studies and R&D
2 Claudia Höhne ISHIP 2008, GSI, November 2008
QCD phase diagram at high baryon densities
[F.Karsch, Z. Fodor, S.D.Katz]
• intermediate range of the QCD phase diagram with high net-baryon densities of strong interest because of
• expected structures as 1st order phase transition and critical point
• chiral phase transition
• deconfinement = chiral phase transition ?
• hadrons and quarks at high ?
• signatures (measurable!) for these structures/ phases?
• how to characterize the medium?
3 Claudia Höhne ISHIP 2008, GSI, November 2008
What do we know from experiment? → Heavy-ion collisions:
• chemical freeze-out curve
• top SPS, RHIC (high T, low B): partonic degrees of freedom, crossover (?)
• RHIC: first steps towards a quantitative characterization of the medium (gluon density, viscosity, energy loss...)
• lower SPS (intermediate T-B): intriguing observations around 30 AGeV!
• SIS, AGS: high density baryonic matter
QCD phase diagram & experiments
[Andronic et al. Nucl. Phys. A 772, 167 (2006).
4 Claudia Höhne ISHIP 2008, GSI, November 2008
Within the next years we'll get a complete scan of the QCD phase diagram with 2nd generation experiments
• LHC, RHIC: bulk observables and rare probes (charm, dileptons)
• RHIC energy scan: bulk observables√s ~ (5)10 GeV – 200 GeV
• NA61: focus on fluctuations(√sNN = 4.5 – 17.3 GeV), A < 120
• NICA: strangeness, bulk observables (√sNN = 3 – 9 GeV)
• CBM: bulk observables and rare probes (charm, dileptons)beam energy 10 – 45 GeV/nucleon(√sNN = 4.5 – 9.3 GeV)
• HADES: bulk observables, dileptonsbeam energy 2 – 10 GeV/nucleon
Experimental scan of QCD phase diagram
[Andronic et al. Nucl. Phys. A 772, 167 (2006).
HADES
CBM, NA61, NICA
LHCRHIC
FAIR beam intensities: up to 109 ions/s
5 Claudia Höhne ISHIP 2008, GSI, November 2008
SPS results
[Andronic et al. Nucl. Phys. A 772, 167 (2006).]
[NA49, PRC 77, 024903 (2008)]
• energy dedendence of hadron production→ changes in SPS energy regime
• discussions ongoing:• hadron gas → partonic phase • baryon dominated → meson dominated matter
• missing: high precision measurements, systematic investigations, correlations, rare probes→ quantitative characterization of the medium!
6 Claudia Höhne ISHIP 2008, GSI, November 2008
0SSppS
BBn
n
Statistical ModelF. Becattini et al., Phys. Rev. C73 (2006), 044905.
High net baryon densities at low SPS energies
BRAHMSPhys. Rev. Lett. 93 (2004), 102301
NA49 (158)Phys. Rev. Lett. 82 (1999), 2471
E802Phys. Rev. C 60 (1999), 064901
NA49 preliminary
Central Pb+Pb/Au+Au
[NA49, compilation C. Blume]• low SPS/ AGS energies: high net-baryon densities at mid-rapidity
• change to nearly net-baryon free region at RHIC
• change of shape most pronounced at SPS energies: peak → dip
construction of total net-baryon distribution:
Sx from stat. model fits
7 Claudia Höhne ISHIP 2008, GSI, November 2008
High net-baryon density matter at CBM
• high baryon and energy densities created in central Au+Au
• remarkable agreement between different models (not shown)
[CB
M p
hysi
cs g
rou
p, C
. F
uchs
, E
. B
ratk
ovsk
aya
priv
. co
m.]
beam energy
max. /0
max [GeV/fm3]
time span
~FWHM
5 AGeV 6 1.5 ~ 8 fm/c
40 AGeV 12 > 10 ~ 3.5 fm/c
8 Claudia Höhne ISHIP 2008, GSI, November 2008
Elliptic flow
KET=mT-m
• all particles flow (even D-mesons!)
• scaling if taking the underlying number of quarks into account!
→ like (all!) quarks flow and combine to hadrons at a later stage (hadronisation)
• data can only be explained assuming a large, early built up pressure in a nearly ideal liquid (low viscosity!)
baryons n=3mesons n=2
[PHENIX, PRL.98:162301,2007]
KE m m mT T T ( ) 1
9 Claudia Höhne ISHIP 2008, GSI, November 2008
Elliptic flow
• data at top SPS support hypothesis of early development of collectivity
• influence of hadronic rescattering phase, resonance decay?
• lack of complete thermalization, viscosity effect?
• larger pt-range needed
Pb+Pb collisions, √sNN = 17.3 GeV
[NA49, G. Stefanek, PoS CPOD2006:030,2006]
10 Claudia Höhne ISHIP 2008, GSI, November 2008
Elliptic flow
→ stiffness of medium (EOS), pressure
• collapse of elliptic flow of protons at lower energies signal for first order phase transition?!
central
midcentral
peripheral [NA49, PRC68, 034903 (2003)]
Elab ~ 30 AGeV
[Paech, Reiter, Dumitru, Stoecker, Greiner, NPA 681 (2001) 41]
?
particle identified flow data for large pt-range!
11 Claudia Höhne ISHIP 2008, GSI, November 2008
AMPT calculations: C.M. Ko at CPOD 2007
Elliptic flow at FAIR
... including charm!
probe for dense matter!
12 Claudia Höhne ISHIP 2008, GSI, November 2008
[A. Andronic, P. Braun-Munzinger, K. Redlich, J. Stachel, arXiv:0708.1488]
Statistical hadronization model (SHM)(c-cbar in partonic phase)
O. Linnyk, E.L. Bratkovskaya, W. Cassing, H. Stöcker,Nucl.Phys.A786:183-200,2007
Hadronic model (HSD)
NN → D Λc NNN → DD NNNN → J/ψ NN
Charm production in hadronic and partonic matter
13 Claudia Höhne ISHIP 2008, GSI, November 2008
Charm production in hadronic and partonic matter
no charm (J/) data below 158 AGeV beam energy
detailed information including phase space distributions!
14 Claudia Höhne ISHIP 2008, GSI, November 2008
Critical point
• critical region might be small
• focussing effect?
• fluctuations would need time to develop
[Schaefer, Wambach, PRD75, 085015 (2007)] [Asakawa, Bass, Mueller, Nonaka, PRL 101, 122302 (2008)]
15 Claudia Höhne ISHIP 2008, GSI, November 2008
Event-by-event fluctuations
[NA49 collaboration, arXiv:0810.5580v2 [nucl-ex]]
• observation might become enormously difficult
• correlation length of sigma field, may become rather small for a finite lifetime of the fireball
• large acceptance needed!
2
2
pt
pt
pt zN
Z
N
ittipt
ttpt
ppZ
ppz
1
[Stephanov, Rajagopal, Shuryak, PRD60, 114028 (1999)]
1st try to identify 1st order phase transition line
fluctuations, correlations with large acceptance and particle identification
16 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM: Physics topics and Observables
Onset of chiral symmetry restoration at high B
• in-medium modifications of hadrons (,, e+e-(μ+μ-), D)
Deconfinement phase transition at high B • excitation function and flow of strangeness (K, , , , )• excitation function and flow of charm (J/ψ, ψ', D0, D, c)• charmonium suppression, sequential for J/ψ and ψ' ?
The equation-of-state at high B
• collective flow of hadrons• particle production at threshold energies (open charm)
QCD critical endpoint• excitation function of event-by-event fluctuations (K/π,...)
predictions? clear signatures?→ prepare to measure "everything" including rare probes → systematic studies! (pp, pA, AA, energy)aim: probe & characterize the medium! - importance of rare probes!!
17 Claudia Höhne ISHIP 2008, GSI, November 2008
The CBM experiment• tracking, momentum determination, vertex reconstruction: radiation hard silicon pixel/strip detectors (STS) in a magnetic dipole field
• hadron ID: TOF (& RICH)• photons, 0, : ECAL
• electron ID: RICH & TRD suppression 104
• PSD for event characterization• high speed DAQ and trigger → rare probes!
• muon ID: absorber + detector layer sandwich move out absorbers for hadron runs
RICHTRD
TOF ECAL
magnet
absorber +
detectorsSTS + MVD
18 Claudia Höhne ISHIP 2008, GSI, November 2008
STS tracking – heart of CBM
Challenge: high track density: 600 charged particles in 25o @ 10MHz
Task
• track reconstruction: 0.1 GeV/c < p 10-12 GeV/c p/p ~ 1% (p=1 GeV/c)
• primary and secondary vertex reconstruction (resolution 50 m)
• V0 track pattern recognition
c = 312 m
radiation hard and fast silicon pixel and strip detectors
self triggered FEE
high speed DAQ and trigger
online track reconstruction!
19 Claudia Höhne ISHIP 2008, GSI, November 2008
• max: up to ~109 tracks/s in the silicon tracker (10 MHz, ~100 tracks/event)
• start scenario for D more like 0.1 MHz → 107 tracks/s
→ fast track reconstruction!
• optimize code, port C++ routines to dedicated hardware
• parallel processing → today: factor 120000 speedup of tracking code achieved!
• long term aim: make use of manycore architectures of new generation graphics cards etc.
Track reconstruction
GeForce 9600
64 core GPU
20 Claudia Höhne ISHIP 2008, GSI, November 2008
Double and triple GEM detectors2 Double-sided silicon microstrip detectors
Radiation tolerance studies for readout electronics Full readout and analysis
chain:
Front-end board with self-triggering
n-XYTER chip Readout controllerData Acquisition
System
online
offline
Go4
AnalysisDetector
signals
Successful test of CBM prototype detector systems with free-streaming read-out electronics using proton beams at GSI, September 28-30, 2008
GSI and AGH Krakow VECC Kolkata KIP Heidelberg
21 Claudia Höhne ISHIP 2008, GSI, November 2008
GSI, Darmstadt, GermanyJINR, Dubna, RussiaKIP, Heidelberg, GermanyVECC, Kolkata, IndiaAGH, Krakow, Poland
90Sr -spectra ...
Detector commissioning:
... in several channels of a silicon microstrip detector
... and in a GEM detector
Operation on the beam line:
Participants:
Beam spot seen on a GEM detector (every 2nd channel read out)
Correlation of fired channels in two silicon microstrip detectors
www-cbm.gsi.de
22 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM hardware R&D
RICH mirror
n-XYTER FEB
Silicon microstrip detector
MVD: Cryogenic operation in vacuum RPC R&D
Forward Calorimeter
GEM
dipole magnet
23 Claudia Höhne ISHIP 2008, GSI, November 2008
Monolithic Acitive Pixel Sensors in commercial CMOS process1010 m2 pixels fabricated, > 99%, x ~ 1.5 – 2.5 m
Micro Vertex Detecor (MVD) DevelopmentArtistic view of the MVD
• mechanical system integration • material for cooling!→ material budget!• vacuum compatibility
die thinned to 50 mglued to support.IPHC, Strasbourg (M. Winter et al.)
24 Claudia Höhne ISHIP 2008, GSI, November 2008
D-meson Simulations• CbmRoot simulation framework, GEANT3 implemented through VMC
• full event reconstruction: track reconstruction, particle-ID (RICH, TRD, TOF), 2ndary vertex finder
• feasibility studies: central Au+Au collisions at 25 AGeV beam energy (UrQMD)
• several channels studied: D0, D±, Ds, c
signal multiplicities from HSD, stat model (SM); e.g. <D+>HSD = 8.410-5, SM ½ less
• important layout studies: MAPS position (5cm , 10cm), thickness (150 m – 500m)
D-
D+
MAPS thickness
D+
efficiency
D+
S/B (2)
150 m 4.2% 9
500 m 1.05% 1.9
D+ → ++K- (c = 312 m, BR 9%)D0 → K-+ (c = 123 m, BR 3.85%)c → pK-+ (c = 60 m, BR 5%)
25 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM feasibility studies
• feasibility studies performed for all major channels including event reconstruction and semirealistic detector setup
D0
c
J/ J/
di-electrons di-muons
' '
26 Claudia Höhne ISHIP 2008, GSI, November 2008
b
p
p
Signal: strange dibaryon
(0)b (cτ=3cm)
M= 10-6, BR = 5%
Background:Au+Au @ 25 AGeV32 per central event11 reconstructable
π K p
χ2primary > 3()
Particle identification with CBM
KS0 Λ
Be prepared for exotica: multi-strange di-baryons
27 Claudia Höhne ISHIP 2008, GSI, November 2008
Detector layout optimization: RICH
• first ansatz: gaseous RICH detector (N2 radiator), ~ 100 m3 volume, 200k channels for photodetector (photomultiplier, pixel size appr. 6x6 mm2), Be mirrors (glass coating)
• optimization process: ~40 m3 volume, CO2 radiator, 55k channels, glass mirrors
RICH + TRD
75% efficiency104 suppression
photodetector:
H8500 MAPMT, UV glass window
15 – 22 hits/ring
28 Claudia Höhne ISHIP 2008, GSI, November 2008
Detector layout optimization: Muon absorber
40 20 20 20 25
30 20 20 20 35
20 20 20 30 35
10 20 30 30 35
central Au+Au collisions at 25 AGeV10 cm Fe
20 cm Fe
30 cm Fe
40 cm Fe
hit density after 1st absorber
total absorber length 125 cm = 7.5 I
29 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM@FAIR – high B, moderate T:
• searching for the landmarks of the QCD phase diagram• first order deconfinement phase transition • chiral phase transition• QCD critical endpoint
→ systematic measurements, rare probes
• characterizing properties of baryon dense matter
• in medium properties of hadrons?
in A+A collisions from 10-45 AGeV (√sNN = 4.5 – 9.3 GeV) starting in 2016 at SIS 300
Summary – physics of CBM
30 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM + HADES @ SIS 100 in 2014
Rigidity Bρ = 100 Tm:
Au beam 10 AGeVNi beam 14 AGeVp beam 30 GeV
HADES: electrons, hadrons
CBM "light" (magnet, Silicon tracker, TOF): p, K, π, Λ, Ξ, Ω, ..., flow, fluctuations, up to Au+Au
31 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM @ SIS 100
• A+A collisions at 8 AGeV beam energy, p+A at 30 GeV/c
• first feasibility studies: charm production for p+C at 30 GeV/c
multiplicities from HSD
1012 events
J/→ +-
S/B ~150
23 %
4 J/ψ→μ+μ- in 109 central events
32 Claudia Höhne ISHIP 2008, GSI, November 2008
CBM collaborationRussia:IHEP ProtvinoINR TroitzkITEP MoscowKRI, St. Petersburg
China:Tsinghua Univ., BeijingCCNU WuhanUSTC Hefei
Croatia:
University of SplitRBI, Zagreb
Portugal: LIP Coimbra
Romania: NIPNE BucharestBucharest University
Poland:Krakow Univ.Warsaw Univ.Silesia Univ. KatowiceNucl. Phys. Inst. Krakow
LIT, JINR DubnaMEPHI MoscowObninsk State Univ.PNPI GatchinaSINP, Moscow State Univ. St. Petersburg Polytec. U.
Ukraine: INR, KievShevchenko Univ. , Kiev
Univ. MannheimUniv. MünsterFZ RossendorfGSI Darmstadt
Czech Republic:CAS, RezTechn. Univ. Prague
France: IPHC StrasbourgGermany: Univ. Heidelberg, Phys. Inst.Univ. HD, Kirchhoff Inst. Univ. Frankfurt
Hungaria:KFKI BudapestEötvös Univ. BudapestIndia:Aligarh Muslim Univ., AligarhIOP BhubaneswarPanjab Univ., ChandigarhGauhati Univ., Guwahati Univ. Rajasthan, JaipurUniv. Jammu, JammuIIT KharagpurSAHA KolkataUniv Calcutta, KolkataVECC Kolkata
Univ. Kashmir, SrinagarBanaras Hindu Univ., Varanasi
Korea:Korea Univ. SeoulPusan National Univ.Norway:Univ. Bergen
Kurchatov Inst. MoscowLHE, JINR DubnaLPP, JINR DubnaCyprus:
Nikosia Univ.
55 institutions, > 400 members
Dubna, Oct 2008