the c ompressed b aryonic m atter experiment at the future accelerator facility in darmstadt
DESCRIPTION
The C ompressed B aryonic M atter experiment at the future accelerator facility in Darmstadt. Claudia Höhne GSI Darmstadt, Germany. RHIC. SPS. SIS300. hadronic phase. nuclei. Motivation. Phase diagram of strongly interacting matter. - PowerPoint PPT PresentationTRANSCRIPT
The Compressed Baryonic Matter experiment at the future accelerator
facility in Darmstadt
Claudia Höhne
GSI Darmstadt, Germany
Claudia Höhne NPDC 18 Prague
nuclei
hadronic phase
SPS
RHIC
lattice QCD : Fodor / Katz, Nucl. Phys. A 715 (2003) 319
SIS300
dilute hadron gasdense baryonic medium
Motivation
Phase diagram of strongly interacting matter
• high T, low B
top SPS, RHIC, LHC
• low T, high B
SIS
• intermediate range ?
low energy runs SPS, AGS
SIS 300 @ GSI !
Highest baryon densities
Critical point?
Deconfinement?
Claudia Höhne NPDC 18 Prague
Motivation
SIS300 light, heavy ions
Phase diagram of strongly interacting matter
• high T, low B
top SPS, RHIC, LHC
• low T, high B
SIS
• intermediate range ?
low energy runs SPS, AGS
SIS 300 @ GSI !
Highest baryon densities
Critical point?
Deconfinement? and region of maximum of relative strangeness production
Claudia Höhne NPDC 18 Prague
Motivation
[Allton et al., Phys. Rev. D68, 014507 (2003)][Allton et al., Phys. Rev. D66, 074507 (2002)] *[Fodor, Katz, JHEP 0404, 050 (2004)]
q/T=1
critical point *
recent improvements in lattice-QCD allow for calculations at finite B :
• large baryon-number density fluctuations at the phase border for q/T=1
• critical point at TE=162 2 MeV, E=360 40 MeV *
intermediate range of phase diagram!
Claudia Höhne NPDC 18 Prague
Known so far ...
Low energy run at SPS (20, 30, 40 AGeV): Relative strangeness production shows ...
• sharp maximum in energy dependence: transition from hadronic to partonic phase?
• dynamical fluctuations which increase towards lower energies: critical point?
[J. Phys. G 30, 1381 (2004)]
4
1
43
2
NN
NNN
s
msF
KKEs
2
NA49
NA49
[J. Phys. G 30, 701 (2004)]
Claudia Höhne NPDC 18 Prague
Known so far ...
Low energy run at SPS (40 AGeV): e+e-
• enhancement of low-mass dilepton pairs, larger at 40 AGeV compared to 158 AGeV
• in medium modification of ?
need more and better measurements also at lower energies!
CERES [Phys. Rev. Lett. 91, 042301 (2003)]
Claudia Höhne NPDC 18 Prague
Known so far ...
A+A collisions at SIS : strangeness production in medium
[M. Lutz, Phys. Lett. B 426, 12 (1998)]KAOS Collaboration
experimental evidence for modification of kaon energy in medium!
• yields, rapidity spectra, azimuthal distributions ...
K+
RBBU KN Pot.
no KN Pot.
Claudia Höhne NPDC 18 Prague
Open questions ...
various QCD inspired models predict a change of the D-mass in a hadronic medium
• in analogy to kaon mass modification, but drop for both, D+ and D-
• substantial change (several 100 MeV) already at =0
• effect for charmonium is substantially smaller
[Mishra et al ., Phys. Rev. C 69, 015202 (2004) ]
Claudia Höhne NPDC 18 Prague
Open questions ...
Consequence of reduced D mass: DD threshold drops below charmonium states
[Mishra et al., Phys. Rev. C 69, 015202 (2004) ]
• decay channels into DD open for ’, c, J/
broadening of charmonium states suppression of J/ lepton pair channel (large fraction of J/ from higher states) (slight) enhancement of D mesons
Claudia Höhne NPDC 18 Prague
Open questions ...
... but even charm production near threshold is not known
[Gorenstein et al J. Phys. G 28 (2002) 2151]
central Au+Au
ccN
Predictions of open charm yield for central A+A collisions differ by orders of magnitude for different production scenarios, especially at low energies
[W. Cassing et al., Nucl. Phys. A 691, 753 (2001)]
Claudia Höhne NPDC 18 Prague
CBM experiment
physics topics observables
deconfinement at high B ?
softening of EOS ?
strangeness production: K,
charm production: J/, D
flow excitation function
Critical point ? event-by-event fluctuations
e+e-
open charm
in-medium properties of hadrons
onset of chiral symmetry restoration at high B
Claudia Höhne NPDC 18 Prague
CBM experiment
observables detector requirements
strangeness production: K,
charm production: J/, D
flow excitation function
event-by-event fluctuations
e+e-
open charm
all-in-one device suitable for every purpose
tracking in high track density environment (~ 1000)
hadron ID
lepton ID
myons, photons
secondary vertex reconstruction
(resolution 50 m)
large statistics: high beam intensity (109 ions/sec.)
high interaction rates (10 MHz)
fast, radiation hard detector
efficient trigger
rare signals!
Claudia Höhne NPDC 18 Prague
CBM detector layout
• tracking, vertex reconstruction: radiation hard silicon pixel/strip detectors (STS) in a magnetic dipole field
• electron ID: RICH1 & TRD (& ECAL) suppression 104
• hadron ID: TOF (& RICH2)
• photons, 0, : ECAL
• high speed DAQ and trigger
beam
target STS
TRDs
TOF
ECAL
RICHs
magnet
Claudia Höhne NPDC 18 Prague
SIS 100 Tm
SIS 300 Tm
U: 35 AGeV
p: 90 GeV
CBM @ FAIR
Facility for Antiproton and Ion Research
„next generation“ accelerator facility:
• double-ring synchrotron
• simultanous, high quality, intense primary and secondary beams
• cooler/ storage rings (CR, NESR, HESR)
Ion and Laser induced plasmas: High energy density in matter
Compressed baryonic matter
Cooled antiproton beam: hadron spectroscopy
Structure of nuclei far from stability
Claudia Höhne NPDC 18 Prague
Tracking with STS
Experimental conditions:• 5cm (1st STS) up to 2 hits/mm2 per event • 100cm (7th STS) < 0.01 hits/mm2
7 planar layers of pixel/ strip detectors:• high precision vertex reconstruction: 2 pixel layers at 5cm, 10 cm downstream of target • fast strip detectors for outer stations (20, 40, 60, 80, 100 cm from target)
Reconstruction efficiency > 95 %Momentum resolution ≈ 0.6 %
frac
tion
of r
econ
stru
cted
tra
cks
p [GeV/c]
Claudia Höhne NPDC 18 Prague
STS
Requirements:
• radiation hardness
• low material budget: d < 200 m
• fast read out
• good position resolution < 20 m
MIMOSA IVIReS/ LEPSI Strasbourg
R&D on Monolithic Active Pixel Sensors (MAPS):
• pitch 20 m
• thickness < 100 m
• single hit resolution ~ 3m
• problem: radiation hardness and readout speed ( event pile up in first 2 STS)
• fallback solution: hybrid detectors (problem: thickness, granularity!)
Claudia Höhne NPDC 18 Prague
electron ID with RICH 1
radiator gas: N2 th = 41 , p,th = 5.7 GeV/c (almost) hadron blind
photodetectors: photomultipliers (or gas detectors)
aim: suppression ~ 104 - 103
-spectrum at for central Au+Au collision at 25 AGeV (UrQMD)
Claudia Höhne NPDC 18 Prague
RICH 1
two mirrors: beryllium covered with glass, R = 450 cm
two focal planes (3.6 m2 each) separated vertically, shielded by magnet yoke
layout RICH: side view
z (beam)
y
rings in focal plane
Claudia Höhne NPDC 18 Prague
TRD
Task: e/ separation > 100, tracking
Setup: 9 layers in three stations (4m, 6m, 8m from target) area per layer 25, 50, 100 m2
efficiency < 1% reachable with 9 layers:
R&D
• for most of the system state-of-the art is appropriate (ALICE)
• inner part: R&D on fast gas detectors in progress (drift chamber/ GEM/ straw tubes)
Requirements:
• high counting rate (up to 150 kHz/cm2)
• fast readout (10 MHz)
• large area
• position resolution ~ 200 m
Claudia Höhne NPDC 18 Prague
Hadron ID with TOF
bulk of hadrons (, K, p) can be well identified with TOF = 80 – 100 ps
identification probability of K- for TOF = 80 ps
Claudia Höhne NPDC 18 Prague
RPC as TOF detector
Challenge for TOF : high counting rate (25 kHz/cm2)
large area (130 m2 @ 10 m)
time resolution ~ 80 ps
R&D Coimbra, Portugal
prototype: single gap counters with metal and plastic electrodes (resistivity 109 cm)
Claudia Höhne NPDC 18 Prague
RICH 2 (?)
Kaon ID by TOF quickly deteriorates above 4 GeV
Option for RICH2 ?e.g. thr = 30 p,thr = 4.2 GeV, pK,thr=15 GeV
problem: ring finding in high hit density environment
Kaon ID by RICH for p > 4 GeV would be desirable
identification probability of K- for TOF = 80 ps Momentum distribution of kaons from D0 decays
Claudia Höhne NPDC 18 Prague
DAQ & trigger architechtureRequirements• efficient detection of rare probes (D, J/, low-mass dilepton pairs): event rate 25 kHz
evaluation of complex signatures• fast: 1st level trigger at full design interaction rate of 10MHz
reconstruct ~ 109 tracks/s, secondary vertices ...• data volume in 1st level trigger ~ 50 Gbytes/s
event size ~ 40kbyte
clock
Detectors
Frontend electronics
Buffer pool
Event builder and selectorstorage
(1Gbyte/s)
self-triggered hit detectionpre-processing
feature extraction
each hit transported as address/ timestamp/ value
extraction of physical signaturestrigger decision
essential performance limitation not latency but throughput
Claudia Höhne NPDC 18 Prague
Feasibility Study: D0
Key variable to suppress background: secondary vertex position
D0 K-+ (c=124.4 m, BR 3.9 0.1%)
central Au+Au @ 25 AGeV (HSD): <D0> ~ 10-3
simulation including various cuts (vz !)
S/B ~ 1
detection rate ~ 13k/h at 1MHz interaction rate
Crucial detector parameters• material in STS• single hit resolution
Claudia Höhne NPDC 18 Prague
Feasibility Study: J/ e+e-
extremely rare signal (central Au+Au @ 25 AGeV ~ 10-5 /event)
6% branching ratio e+e-background from various sources: conversion, Dalitz decays of 0 and , , misidentified very efficient cut on single electron pt, pair opening angle
S/B > 1 should be feasible
Claudia Höhne NPDC 18 Prague
Feasibility Study: e+e-
branching ratio ~ 4.44 10-5 () – 3.1 10-4 ()
background from various sources: conversion, Dalitz decays of 0 and , misidentified no easy pt-cut as for J/ sophisticated cutting strategy necessary
depends crucially on elimination of conversion pairs by tracking
and charged pion discrimination by RICH and TRD ( 104 !)
idealized simulation:• no momentum resolution• no misidentification
• cut on pt, pair opening angle, prim. vertex track S/B 0.5-1
Claudia Höhne NPDC 18 Prague
Status of project
So far ...
• November 2001 Conceptual Design Report, Cost estimate 675 M €
• July 2002 German Wissenschaftsrat recommends realisation
• February 2003 German Federal Gouvernment decides to build the facility, will pay 75%
• January 2004 CBM Letter of Intent submitted
• CBM collaboration is formed: 250 scientiest from 39 institutions
• work in progress: detector design and optimization
R&D on detector components
feasibility studies of key observables
• next step: Technical Proposal January 2005
• could run in 2012!
Claudia Höhne NPDC 18 Prague
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
Romania: NIPNE Bucharest
Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaLIT, JINR DubnaPNPI GatchinaSINP, Moscow State Univ.
Spain: Santiago de Compostela Univ. Ukraine: Univ. Kiev
Hungaria:KFKI BudapestEötvös Univ. Budapest
Italy: INFN Frascati
Korea:Korea Univ. SeoulPusan National Univ.
Norway:Univ. Bergen
Poland:Jagiel. Univ. Krakow Silesia Univ. KatowiceWarsaw Univ.Warsaw Tech. Univ. Portugal: LIP Coimbra
Claudia Höhne NPDC 18 Prague
CBM time schedule
Subproject 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Si-Tracker
RICH
TRD
TOF-RPC
ECAL
Trigger/DAQ
Electronics
Magnet
Infrastructure
simulations, R&D, design Prototyping Construction Installation, test
Milestones: 1. Technical Proposal begin of 2005 2. Technical Design Report end of 2007
Claudia Höhne NPDC 18 Prague
Hit rates for 107 minimum bias Au+Au collisions at 25 AGeV:
Rates of > 10 kHz/cm2 in large part of detectors ! main thrust of our detector design studies
experimental conditions
Claudia Höhne NPDC 18 Prague
CBM R&D working packages
Feasibility, Simulations
D Kπ(π)GSI Darmstadt, Czech Acad. Sci., RezTechn. Univ. Prague
,ω, e+e-
Univ. KrakowJINR-LHE Dubna
J/ψ e+e-
INR Moscow
Hadron ID Heidelberg Univ,Warsaw Univ.Kiev Univ. NIPNE BucharestINR Moscow
GEANT4: GSI
TrackingKIP Univ. HeidelbergUniv. MannheimJINR-LHE Dubna
Design & constructionof detectors
Silicon PixelIReS StrasbourgFrankfurt Univ.,GSI Darmstadt,RBI Zagreb,Univ. Krakow
Silicon StripSINP Moscow State U.CKBM St. PetersburgKRI St. Petersburg
RPC-TOFLIP Coimbra, Univ. Santiago de Com.,Univ. Heidelberg,GSI Darmstadt,Warsaw Univ.NIPNE BucharestINR MoscowFZ RossendorfIHEP ProtvinoITEP Moscow
Fast TRDJINR-LHE, DubnaGSI Darmstadt,Univ. MünsterINFN Frascati
Straw tubesJINR-LPP, DubnaFZ RossendorfFZ JülichTech. Univ. Warsaw
ECAL ITEP Moscow GSI DarmstadtUniv. Krakow
RICH IHEP Protvino GSI Darmstadt
Trigger, DAQKIP Univ. HeidelbergUniv. MannheimGSI DarmstadtJINR-LIT, DubnaUniv. BergenKFKI BudapestSilesia Univ. KatowiceUniv. Warsaw
MagnetJINR-LHE, DubnaGSI Darmstadt
AnalysisGSI Darmstadt,Heidelberg Univ,
Data Acquis.,Analysis
Claudia Höhne NPDC 18 Prague
Acceptance of D0 and J/p
t [G
eV
/c]
D0 J/ψ
Claudia Höhne NPDC 18 Prague
misidentification
0 %
1 %0.1 %
0.01 %
Claudia Höhne NPDC 18 Prague
Granularity:inner region 2x2 cm2
intermediate region 5x5 cm2
outer region 10x10 cm2
Lead-scintillator calorimeter:• 0.5 – 1 mm thick tiles• 25 X0 total length• PM read out
Distance between electron and closest track in the innermost region
Tests of detector module prototype: July 2004 at CERN
Design of ECAL
Design goals of sampling calorimeter:• energy resolution of 5/E (%)• high-rate capability up to 15 kHz/cm2
• e//() discrimination of 25-200• total area ~200m2
Claudia Höhne NPDC 18 Prague
FAIR @ GSI