The CBM experiment - exploring the QCD phase diagram at high net baryon densities - Claudia Höhne, GSI Darmstadt CBM collaboration The CBM experiment physics case, observables detector layout feasibility studies and R&D of detector components

Claudia Höhne DPG Frühjahrstagung, Gießen, März Physics case Compressed Baryonic 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 in A+A collisions from AGeV starting in 2015 physics program complementary to ALICE measurement of charm production at threshold A. Andronic et al., Nucl. Phys. A 772, 167 (2006).

Claudia Höhne DPG Frühjahrstagung, Gießen, März High density matter high baryon and energy densities created in central Au+Au collisions remarkable agreement between different models max. net baryon densities from AGeV ~ fm -3 ~ (6 – 12) 0 (net baryon density = 1 fm -3 ~6 0 ) max. excitation energy densities from AGeV ~ (0.8 – 6) GeV/fm 3 ( * = – m N, total energy density) net baryon density excitation energy density [CBM physics group, J. Randrup priv. com.]

Claudia Höhne DPG Frühjahrstagung, Gießen, März 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', D 0, D, c ) sequential melting of J/ψ and ψ', charmonium suppression 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,...) mostly new measurements CBM Physics Book (theory) in preparation

Claudia Höhne DPG Frühjahrstagung, Gießen, März 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 10 4 PSD for event characterization high speed DAQ and trigger rare probes! muon ID: absorber + detector layer sandwich move out absorbers for hadron runs MVD + STS aim: optimize setup to include both, electron and muon ID (not necessarily simultaneously)

Claudia Höhne DPG Frühjahrstagung, Gießen, März CbmRoot simulation framework detector simulation (GEANT3) full event reconstruction: track reconstruction, add RICH, TRD and TOF info result from feasibility studies in the following: central Au+Au collisions at 25 AGeV beam energy

Claudia Höhne DPG Frühjahrstagung, Gießen, März STS tracking Challenge: high track density 600 charged particles in 25 o Task track reconstruction: 0.1 GeV/c < p GeV/c p/p ~ 1% (p=1 GeV/c) primary and secondary vertex reconstruction (resolution 50 m) V 0 track pattern recognition D K - (c = 317 m) D 0 K - + (c = 124 m) silicon pixel and strip detectors

Claudia Höhne DPG Frühjahrstagung, Gießen, März Open charm production D 0 K - + (c = 124 m) = first MAPS detector at 10cm ~53 m secondary vertex resolution proton identification with TOF central Au+Au collisions, 25 AGeV central Au+Au, 25 AGeV

Claudia Höhne DPG Frühjahrstagung, Gießen, März " 280 µm Microstrip SensorsTracking Stations layout studies module design J. Heuser HK 22.2 Silicon Strip Sensor R&D

Claudia Höhne DPG Frühjahrstagung, Gießen, März Fast self-triggered readout electronics NXYTER chip produced; DETNI GSI test system under construction micro- strip sensor K. Solvag HK 34.8

Claudia Höhne DPG Frühjahrstagung, Gießen, März Dileptons - electrons low-mass vector mesons: try to reject large physical background ( - conversion, Dalitz decays) by high performance tracking J/ : cut on p t (1.2 GeV/c) high purity of electron identification needed! ( -suppr. > 10 4 achievable) S/B=1.7 eff. 12% J/ meson low-mass vector mesons S/B = 0.2 eff. 7.5% T. Galatyuk HK k events = 10s of beam time central Au+Au, 25 AGeV events

Claudia Höhne DPG Frühjahrstagung, Gießen, März Dileptons - muons low efficiency for soft muons investigate momentum dependent identification phantastic J/ (p t > 1 GeV/c), even ' should be accessible however: high hit densities in detectors! J/ meson (add 1m Fe) low-mass vector mesons (1.25 m Fe) S/B = 0.4 eff. 1.3% eff. 20% A. Kiseleva HK 19.4 central Au+Au, 25 AGeV events

Claudia Höhne DPG Frühjahrstagung, Gießen, März First test beam data hit density? without Pb converter with Pb converter (1.5 cm ~ 3X 0 ) hit densities after absorbers? (reliability of simulation?) first results from test beam (6 GeV/c) at CERN, PS on high granularity gas detectors (ALICE prototypes): increase hit density in GEANT 3 appr. by factor 2 ADC counts

Claudia Höhne DPG Frühjahrstagung, Gießen, März CBM collaboration Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg China: CCNU Wuhan USTC Hefei Croatia: RBI, Zagreb Portugal: LIP Coimbra Romania: NIPNE Bucharest Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Nucl. Phys. Inst. Krakow LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Ukraine: Shevchenko Univ., Kiev Cyprus: Nikosia Univ. Univ. Mannheim Univ. Münster FZ Rossendorf GSI Darmstadt Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Kaiserslautern Hungaria: KFKI Budapest Eötvös Univ. Budapest India: VECC Kolkata SAHA Kolkata IOP Bhubaneswar Univ. Chandigarh Univ. Varanasi IlT Kharagpur Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna 46 institutions > 400 members Strasbourg, September 2006 CBM related talks: M. Klein-Bösing HK 16.8T. Galatyuk HK 19.3 A. Kiseleva HK 19.4J. Heuser HK 22.2 K. Solvag HK 34.8D. Gonzalez-Diaz HK 47.4 S. Gorbunov HK 53.1C. Steinle HK 53.4 CBM related poster: C. Müntz HK 49.23