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This article discusses the QCD phase diagram at high baryon densities and explores potential phase transitions and equilibration processes. It also highlights the importance of high precision data and rare probes in studying the QCD phase diagram. The feasibility studies and detector R&D for the CBM experiment at SIS100 and SIS300 are also mentioned.
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Hadronic Matter at High Baryon Density Claudia Höhne, GSI Darmstadt
At the end of this meeting …. … let’s look into the future:
Outline • Introduction & Motivation • QCD phase diagram → high baryon densities! • → phase transitions (quarkyonic phase?), CP? • high baryon density – hadron gas – phase transition? • multistrange hadrons, centrality dependence of K/p ratio, K/p fluctuations, dileptons, charm production • CBM experiment at SIS100 and SIS300 • feasibility studies • detector R&D
The QCD Phase Diagram • crossover between hadronic and deconfined phase at low mB and high T • freeze-out curve (T,mB) • high precision data from RHIC (and soon LHC) • equilibration! • phase diagram at high mB ? • quarkyonic phase? • phase transition(s)? • equilibration? • critical point/ triple point? • need for high precision data including rare probes! A. Andronic et al., Nucl. Phys. A 772, 167 (2006). [A. Andronic et al., arXiv:0911.4806 ]
Future explorations complete scan of the QCD phase diagram with modern, 2nd generation experiments on the horizon! • RHIC beam energy scan • - evolution of medium properties • - “turn-off” of established signatures • - search for CP and PT • NA61 at SPS (2007 acc. by SPSC) • - search for CP and PT in energy-system size scan • both essentially limited to high yield observables • - RHIC: energy dependent • FAIR and NICA • - new accelerator projects • - FAIR: high intensities! → rare probes! 30A GeV Field driven by experimental data!
Chemical freeze-out: a different view • high (net-)baryon and energy densities created in central Au+Au collisions [J. Randrup, J. Cleymans PRC74, 047901 (2006)]
Limiting temperature at √sNN ~ 10 GeV • chemical freeze-out (fit T, mB, V): temperature saturates for √sNN > 10 GeV although energy density (and initial T) still increases • → deconfinement phase boundary reached, additional energy goes into heating the QGP • occurs at the same energy at which mesons start to carry the larger part of the entropy SIS 100 SIS 100 s/T3 SIS 300 SIS 300 [H.Oeschler et al., J.Phys.G 32, 223 (2006)] [A. Andronic et al., Phys. Lett. B 673 (2009) 142]
Multistrange Hadrons • thermal equilibration also at low energies (high mB) in particular concerning multistrange hadrons? SIS 300 SIS 100 [A. Andronic et al., Phys. Lett. B 673 (2009) 142]
HADES: Sub-threshold X- production [HADES: arXiv: 0911.0516] • Ar+KCl reactions at 1.76A GeV • X- yield by appr. 1 order of magnitude higher than thermal yield • strangeness exchange reactions like • (Y=L,S) ? [HADES: PRL103, 132301, (2009)]
K/p ratio – centrality dependence • K/p ratio in central Pb+Pb (Au+Au) collisions well described by thermal model • centrality dependence? [PHENIX, PRC 69 (2004) 034909] [STAR, PRC79 (2009) 034909] • high energies: fast rise and saturation behavior well understood in terms of percolation [1] or Core-Corona model [2] [1] CH, F. Pühlhofer, R. Stock, Phys. Lett. B 640 (2006) 96 [2] K.Werner, PRL 98, 152301 (2007)
K/p ratio – centrality dependence • lower energies? • → same shape of centrality dependence for √sNN > 17 GeV • → changing dependence for lower energies?! • → relation to hadron rescattering/ freeze out at phase transition? • other strangeness carriers – in particular X, W ? [KAOS, JPG 31 (2005) S693] [E802, PRC 60 (1999) 044904] [NA49 preliminary, QM09] [black & red lines: CH, F. Pühlhofer, R. Stock, PLB 640 (2006) 96]
K/p fluctuations • particle ratio fluctuations as sign for 1st order phase transition or CP? • no data below 20 AGeV beam energy • interpretation of measurements under discussion • one suggestion: [NA49, Phys.Rev.C79:044910,2009] scaling with Volume (Nch) or number of K (NK) in acceptance? → test with centrality dependence!
K/ Fluctuations • K/p fluctuations might be dominated by number of kaons [D. Kresan, CPOD 2009, arXiv:0908.2875] • different scaling for energy and centrality dependences • additional contributions from fluctuating cluster sizes/ core-corona contributions?! NA49 preliminary
Dileptons • dileptons as direct probe of the high density phase • CERES at 40 and 158 AGeV beam energy: excess higher at lower energy → importance of baryon density! • HADES at SIS18: study coupling to baryons! HADES, arXiv: 0907.3690 – QM09 explains C+C! [CERES: Eur.Phys.J.C 41, 475 (2005)] preliminary
Charm propagation • Propagation of produced charm quarks in the dense phase – • quark like or (pre-)hadron like? • charmonium to open charm ratio as indicator – measure both! • indications of collectivity? • first charm measurements in A+A below 158 AGeV! • aim at detailed information including phase space distributions, flow! [HSD: O. Linnyk et al., Int.J.Mod.Phys.E17, 1367 (2008)] [SHM: A. Andronic et al., Phys. Lett. B 659 (2008) 149]
CBM @ FAIR + HADES • CBM and HADES at SIS 100 and SIS 300 • systematic exploration of high baryon density matter in A+A collisions from 2 – 45 AGeV beam energy with 2nd generation experiments • explore the QCD phase diagram, chiral symmetry restauration
HADES and CBM startversion at SIS 100 Module 0: SIS100 Module 1: CBM Cave, APPA hall Module 2: SFRS + R3B Module 3: Anti-proton facility Module 4: Low-E NUSTAR, NESR, FLAIR, APPA-cave Module 5: RESR
Nuclear matter physics at SIS 100 s s u d s u Λ ? Λ • Nuclear equation-of-state: What are the properties and the degrees-of-freedom of nuclear matter at neutron star core densities? • Hadrons in dense matter: What are the in-medium properties of hadrons? Is chiral symmetry restored at very high baryon densities? • Strange matter: Does strange matter exist in the form of heavy multi-strange objects? • Heavy flavor physics: How ist charm produced at low beam energies, and how does it propagate in cold nuclear matter?
CBM: Physics topics and Observables • The equation-of-state at high B • collective flow of hadrons • particle production at threshold energies (open charm) • 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' ? CBM Physics Book submitted! • QCD critical endpoint • excitation function of event-by-event fluctuations (K/π,...) • Onset of chiral symmetry restoration at high B • in-medium modifications of hadrons (,, e+e-(μ+μ-), D) Systematics & precision!! → characterization of the created medium!
Particle multiplicities Particle multiplicity ∙ branching ratio for min. bias Au+Au collisions at 25 GeV (from HSD and thermal model) SPS Pb+Pb 30 A GeV
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, p0, h: ECAL • PSD for event characterization • high speed DAQ and trigger → rare probes! • electron ID: RICH & TRD • p suppression 104 • muon ID: absorber + detector layer sandwich • move out absorbers for hadron runs ECAL TOF TRD RICH absorber + detectors STS + MVD magnet
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 Dp/p ~ 1% (p=1 GeV/c) • primary and secondary vertex reconstruction (resolution 50 mm) • V0 track pattern recognition radiation hard and fast silicon pixel and strip detectors ct = 312 mm self triggered FEE high speed DAQ and trigger online track reconstruction! fast & rad. hard detectors!
Parallelization in CBM Reconstruction ! • fast event reconstruction is a must for CBM! +March 2009 +October 2009 • DELL Server with: • Core i7/Nehalem2x(Xeon X5550 4x2.66 GHz, 8 MB L3 cache) • DDR3-1333 36 GB main memory • NVIDIA GTX 295 2x240 FPUs, 1792 MB • optional LRB
CBM feasibility studies 1010 events • feasibility studies performed for all major channels including event reconstruction and semirealistic detector setup D0 di-electrons di-muons r w f Lc r w f J/y J/y y' y'
Di-electrons at SIS300 • CBM has acceptance for di-electron pairs down to lowest pt and Minv • feasibility study for central Au+Au collisions, 25 AGeV, 200k events detected pairs pt < 0.2 GeV/c
Feasibility studies for CBM at SIS 100 • charm production in pC collisions with 30 GeV/c p-beam! • open charm: STS + dipole magnet, TOF • charmonium: STS, dipole magnet, reduced muon detector • study charm production at threshold, cold nuclear matter effects, reference data for later A+A collisions 6 J/ψ recorded in 1010 events (b=0) (3·104 J/ψ per week) J/y→ m+m- eff = 11.6 % 4 cut
Development of the Silicon Tracking System (STS) Sensor development: double-sided micro-strips, stereo angle 15o, pitch 60 μm 300 μm thick, bonded to ultra-thin micro-cables, radiation hardness Prototypes (sensors, electronics, cables for beam tests: STS in thermal enclosure Detector planes: ultra-light weight ladder structure
STS demonstrators in testbeam @ GSI (Sep ’09) with 4 n-XYTER chips fully reading out one CBM baby detector tracker boards Q2, Q4, Q6 beam reference tracking telescopewith 3 or 4 stations D1, D2 rotation around vertical axis 20 deg boards D1 + D2
Beam spot in Q6 … further analysis ongoing
Micro Vertex Detecor (MVD) Development Artistic view of the MVD • mechanical system integration • material for cooling! • → material budget! • vacuum compatibility • Monolithic Acitive Pixel Sensors in commercial CMOS process • 1010 mm2 pixels fabricated, • e > 99%, Dx ~ 1.5 – 2.5 mm die thinned to 50 mmglued to support. IPHC, Strasbourg (M. Winter et al.)
Sensors for the MVD Topic CBM wish list MAPS (2003) MAPS (2009) Digital camera with 8.2 MPixel – CMOS MAPS Single point resolution ~ 5µm 1.5µm ~ 1 µm Material budget few 0.1% X0 ~ 0.1% X0 ~ 0.05% X0 >1013 neq/cm² Rad. hard. non-io. ~1012 neq/cm² > 3x1013 neq/cm² Rad. hard. io > 3 Mrad 200 kRad > 1 MRad Time resolution < 30 µs ~ 1 ms ~ 50 µs • Monolithic Active Pixel Sensors • (MAPS, also CMOS-Sensors) • Invented by industry (digital camera) • Modified for charged particle detection since 1999 by IPHC Strasbourg • Also foreseen for ILC, STAR…
The MVD-demonstrator test @ CERN (Nov. 2009) • 4 x MIMOSA-20 • 4 x 640 x 320 pixel • 30 x 30 µm² pixel • Serial analog readout • Vacuum compatible cooling • First test of MVD demonstrator at CERN-SPS (Nov ’09) • two single sided modules operated in coincidence “MVD telescope”, stations can be correlated by time stamps • noise of the modules was 25-35 electrons (as expected from lab) • data analysis ongoing
RICH development • develop robust but very efficient and high performant RICH detector based on industrial available components • adopt self-triggered readout electronics MAPMT (H8500, Hamamatsu) mirror + mount
MAPMT beamtest for RICH @ GSI (Sep ’09) • plexiglass radiator for Cherenkov light generation by protons • self-triggered readout electronics based on the n-XYTER adopted to the PMT readout (attenuation!): negligible noise level if requiring beam coincidence 3.5 hits/events → single photon counting with self triggered readout! → further analysis ongoing Hamamatsu H8500
CBM beamtest @ GSI (Sep 2009) TriggerS3+S4 RICH GEM STS DABC + Go4, Slow Control • combined beam time CBM & PANDA • 9 days of ~ 2 hours beam per day • protons, 2.0 GeV, ~ 104 p/s
DAQ in September 2009 Test Beam FEB1nxGen D1 DABC FEB4nxBT FEB1nxGen D2 FEB4nxBT ROC ROC ROC ROC ROC ROC Eth Eth Eth Eth Eth Eth A A A A A A SYNC-M SYNC-S SYNC-S SYNC-S SYNC-S SYNC-S OnlineAnalysisGo4 B B B B B B AUX AUX AUX AUX AUX AUX FEB1nxGen GEM1VECC 6 ROC's8 FEB's12 n-XYTER FEB1nxGen GEM2VECC FEB1nxGen FEB1nxGen RICH/MAPMT Beam Tag/Trigger discr BEAM. • system test! • self-triggered FEE for all detectors, event building based on time stamps
Summary • CBM@FAIR – high mB, moderate T: • exploration of QCD phase diagram at high baryon densities at SIS 100 and SIS 300 (2-45 AGeV beam energy) • together with HADES unique possibility of characterizing properties of baryon dense matter • implementation of increasingly • realistic detector response in • simulations, parallelization of event • reconstruction, first physics • performance studies • detector R&D ongoing • several beamtests in 2009: • RPC • STS, GEM, RICH • MVD [A. Andronic et al., arXiv:0911.4806 ]
CBM collaboration France: IPHC Strasbourg Korea: Korea Univ. Seoul Pusan National Univ. India: Aligarh Muslim Univ., Aligarh IOP Bhubaneswar Panjab Univ., Chandigarh Gauhati Univ., Guwahati Univ. Rajasthan, Jaipur Univ. Jammu, Jammu IIT Kharagpur SAHA Kolkata Univ Calcutta, Kolkata VECC Kolkata China: Tsinghua Univ., Beijing CCNU Wuhan USTC Hefei Croatia: University of Split RBI, Zagreb Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Norway: Univ. Bergen Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Nucl. Phys. Inst. Krakow Univ. Mannheim Univ. Münster FZ Rossendorf GSI Darmstadt Univ. Wuppertal Cyprus: Nikosia Univ. Czech Republic: CAS, Rez Techn. Univ. Prague Portugal: LIP Coimbra Romania: NIPNE Bucharest Bucharest University Hungaria: KFKI Budapest Eötvös Univ. Budapest Univ. Kashmir, Srinagar Banaras Hindu Univ., Varanasi Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Ukraine: INR, Kiev Shevchenko Univ. , Kiev 56 institutions, > 400 members Split, Oct 2009