ICPAGQP 2005, Kolkata Probing dense baryonic matter with time-like photons Dilepton spectroscopy...
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Transcript of ICPAGQP 2005, Kolkata Probing dense baryonic matter with time-like photons Dilepton spectroscopy...
ICPAGQP 2005, Kolkata
Probing dense baryonic matter with time-like photons
Dilepton spectroscopy from 1 to 40 AGeV at GSI and FAIR
Joachim Stroth
Univ. of Frankfurt
ICPAGQP 2005, Kolkata
Toneev et al., 2004
The physics case
What are the properties of dense nuclear matter?
Dense matter Freeze-outFirst chance collisions
Its macroscopic properties depend on the microscopic structure!
ICPAGQP 2005, Kolkata
The physics case
Probe the electromagnetic structure of (hot) and dense nuclear matter in the time-like region!
– What is the relevant excitation spectrum as the matter density increases?
– Where are the limits of hadronic existence?
Additional self-energy terms due to meson-
baryon coupling
J. Wambach et al.
0,0
,
T
T
Densebaryonicmatter
Partial restoration of chiral symmetry
ICPAGQP 2005, Kolkata
Probing the interior of compressed matter
pn
++
K
p
e+
e-
Low-mass vector mesonsIn-medium spectral functions
ICPAGQP 2005, Kolkata
The HADES spectrometer
• Geometry Full azimuth , polar angles 18o - 85o
Pair acceptance 0.35 About 80.000 detector channels
• Fast particle identification RICH
CsI solid photo cathode, No 80, C4F10 radiator
TOF (Scintillator rods)
TOFino (Scintillator paddles) temporary solution, RPC in future
Pre-Shower 18 pad chambers & lead converters
• Momentum measurement ILSE, super conducting toroid
B = 0.35 Tm
MDC Multi-wire drift chamber, single cell resolution 100 m
1 m
ICPAGQP 2005, Kolkata
ICPAGQP 2005, Kolkata
Experimental runs
• November 2001: commissioning run target = 5% – C+C 2 AGeV LVL1 triggered events (Mch.>3) : 45 Mevents45 Mevents
– C+C 1 AGeV LVL1 trigger : 7.3 Mevents7.3 Mevents– full coverage with inner MDC chambers (p/p 10% at 0.7 GeV/c)
• November 2002: C+C 2 AGeV, commissioning and physics runs – target= 2 x 2.5%, 56% LVL1 trigger + 44% LVL2 trigger 220 Mevents220 Mevents– 6 outer drift chambers (MDC) in 4 sectors
• October 2003: p+p commissioning run (1 GeV, 2 GeV) – full coverage with outer MDC III (4 MDC IV) (p/p 1.5 % at 0.7 GeV/c)
• February 2004: p+p 2GeV production run– target 5 cm l-H2 400 Mevents400 Mevents
• August 2004: C+C 1AGeV production run– 3x1.5 % target, 56% LVL1 trigger + 44% LVL2 trigger 650 Mevents650 Mevents
ICPAGQP 2005, Kolkata
Fast 2nd level trigger
up to 20 kHz LVL1Fast multiplicity trigger
full event information digitised.
on-line selection of electron candidates
LVL2 triggered events are transported to mass storage
Suppression 10 - 100
ICPAGQP 2005, Kolkata
On-line off-line comparison
• Trigger condition used in November 2002 run:
– At least one good electron candidate
– Ring matched with META hit
• Data rate reduced by 92 %
• Pair enhancement by factor of 9
• Single lepton efficiency of IPUs + matching 62%(pairs 82%)
Me+e- [MeV/c2]
Yie
ld /
even
t [a
.u]
e+e- > 40
Scaled down by 9.2 ! LVL2
LVL1
No bias on data
ICPAGQP 2005, Kolkata
C+C @ 2 A GeV "Nov’02"
preliminary
No Efficiency / Acceptance Correction
• Minimal tracking analysis
• No in-medium contributions in the simulation.
ICPAGQP 2005, Kolkata
C+C @ 1 A GeV “Aug'04”
All N+-
B+- = 2*sqrt(N++*N--)
S+- = N+- - B+-
M [MeV/c2]
Yie
ld /
1 M
e V/c
2
very preliminary
No Efficiency / Acceptance Correction
ICPAGQP 2005, Kolkata
Meson-baryon coupling and in-medium spectral functions
Starting in 2006!
• Precision spectroscopy at nuclear ground state density
• Invariant mass resolution with outer tracking is 1 % in the vector meson mass region
M. Effenberger, Giessen
One possible scenario
e+
e-
208Pb
-
n
W.Schoen et al.
Acta Phys.PolB27(1996)2959
ICPAGQP 2005, Kolkata
nuclear matter at high densitiesCBM experiment
Facility for Antiproton and Ion Research
FAIRFAIR
Staged realization
ICPAGQP 2005, Kolkata
The future of dielectron spectroscopy at FAIR
Heavy ion collisions Heavy ion collisions at interaction rates of up to 10at interaction rates of up to 1077 Hz Hz
andand
beam energies from 2 to 40 GeV/ubeam energies from 2 to 40 GeV/uCBM Detector
HADES
E < 10 AGeV
E > 10 AGeV
Talk by Peter Sengeron Wednesday
ICPAGQP 2005, Kolkata
e+ e-e+e-
HADES acceptance at higher energies
ThermalSource
Accepted
YcmYcmYcmYcm
Y
pt
C+C 2 AGeV C+C 8 AGeV
1 GeV/c
1 GeV/c
0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3
J. Novotny, HADES collaboration meeting 2003
Electrons from:o-Dalitz, -Dalitz, , (-Dalitz), 40 % of geometrical cross section
Simulation
ICPAGQP 2005, Kolkata
HADES with beam from SIS100
Compared to 2 A GeV– acceptance 40% lower– yields 2 orders of magnitude higher
Simulation
ICPAGQP 2005, Kolkata
Experimental concept
Perform momentum measurement in a 1m3 volume with 1 T magnetic field.
Possibly a flexible configuration to optimize performance for different physics cases..
Both options, electronselectrons and muonsmuons are investigated.
Detector configuration CBM experimentHigh quality tracking to identify
"background" tracks (conversion, 0)
ICPAGQP 2005, Kolkata
Dilepton spectroscopy at GSI and FAIR
Final C+C spectra 1 and 2 AGeV
, p, d, A on lH2, A
A+A heavy collision systems
2005
2010
2015tim
e [y
ear
AC
]
Dilepton spectroscopy in A+A at 10-40 AGeV
A+A medium up to 8-10 AGeV
Systematic study of the microscopic properties of dense baryonic matter
ICPAGQP 2005, Kolkata
The Collaboration
Cyprus
University of Cyprus
France
Institut de Physique Nucléaire d'Orsay
Czech Republic
Nuclear Physics Institute, Rez
Czech Academy of Sciences, Rez
Germany
GSI, Darmstadt
FZR, Dresden
Johann Wolfgang Goethe-Universität Frankfurt
Justus Liebig Universität Giessen
Technische Universität München
Italy
INFN Catania
Università di Catania
INFN Milano
Università di Milano
Poland
Jagiellonian University of Cracow
Russia
LHE at JINR, Dubna
Institute for Nuclear Research, Moscow
MEPHI, Moscow
ITEP, Moscow
Spain
University of Santiago de Compostela
Universidad de Valencia-CSIC
ICPAGQP 2005, Kolkata
The CBM Collaboration
Croatia: RBI, Zagreb
Cyprus: Nikosia Univ. Czech Republic:Czech Acad. Science, RezTechn. Univ. Prague France: IReS Strasbourg
Germany: Univ. Heidelberg, Phys. Inst.Univ. HD, Kirchhoff Inst. Univ. FrankfurtUniv. Mannheim Univ. MarburgUniv. MünsterFZ RossendorfGSI Darmstadt
Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaLIT, JINR DubnaObninsk State Univ.PNPI GatchinaSINP, Moscow State Univ. St. Petersburg Polytec. U.
Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ. , KievUniv. of Kharkov
Hungaria:KFKI BudapestEötvös Univ. Budapest
Korea:Korea Univ. SeoulPusan National Univ.
Norway:Univ. Bergen
Poland:Krakow Univ.Warsaw Univ.Silesia Univ. Katowice Portugal: LIP Coimbra
Romania: NIPNE Bucharest
ICPAGQP 2005, Kolkata
Lepton candidate selection
Events with lepton multiplicity 1 in LVL1 triggered events: 1.2 %
Require META and RICH signal (LVL2)
+ matching with fully reconstructed tracks
linear z axis !
log. z axis !
yie
ld [
arb
. u
nit
s]
cut on
ICPAGQP 2005, Kolkata
Signal to Background Nov02
preliminary
Ne+e- - CB
CBS/B =
<S/B> ~ 4:1 (M < 100 MeV/c2)
<S/B> ~ 1:2 (M > 100 MeV/c2)
inv. mass [MeV/c2]
S/B
Mass range Mass range [MeV/c2]:[MeV/c2]:
0 -> 1500 -> 150 150 -> 610150 -> 610 610 -> 1000610 -> 1000
Signal e+e- Signal e+e- pairspairs
14943 +- 7214943 +- 72 1357 +- 131357 +- 13 65 +- 965 +- 9
data
simulation
C+C Nov ‘02
ICPAGQP 2005, Kolkata
Dielectrons in CBM
R. Karabowicz, Kraków, CBM Collaboration Meeting
ICPAGQP 2005, Kolkata
Experiments with pion beams
• in-beam tracking of pions
• p and A reactions
Eth
resh
[GeV
]
Mx [GeV/c2]
/
pp->ppX
-p->Xn