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The physics of dense baryonic matter: From HADES to CBM

The physics of dense baryonic matter: From HADES to CBM. DM2010 International Workshop on High Density Matter STIAS, Stellenbosch, South Africa Joachim Stroth, Goethe-University Frankfurt / GSI. Agenda. Introduction Dileptons from light collision systems Vector meson production

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The physics of dense baryonic matter: From HADES to CBM

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  1. The physics of dense baryonic matter:From HADES to CBM DM2010 International Workshop on High Density Matter STIAS, Stellenbosch, South Africa Joachim Stroth, Goethe-University Frankfurt / GSI

  2. Agenda • Introduction • Dileptons from light collision systems • Vector meson production • Strangeness production • The future at SIS18, SIS100 and SIS300 • Summary

  3. The HADES experiment @ GSI

  4. The HADES Mission • Search (in this region) for • medium-effects • partial restoration of chiral symmetry • onset of decofinement • Beam energies of 1-2 GeV/u Phase 1 (2002 - 2008) -> Upgrade • Light collision systems (limited granularity of TOF system) Phase 2 (2010 – 2015) • Heavy collision systems, p-induced reactions Phase 3 (FAIR/SIS100) • Excitation function up to 10 GeV/u (medium-heavy systems)

  5. Partial restoration of chiral symmetry From vector manifestation of hidden local symmetry: “... to suggest that the dileptons measured in relativistic heavy-ion collisions do not provide direct information on the spontaneous breaking of chiral symmetry and hence on the mechanism for mass generation of light-quark hadrons.” Brown, Harada et al. Prog.Theor.Phys.121:1209-1236,2009 SPS g,p-,p - beams RHIC LHC SIS 18 SIS 200 T [MeV] 300 R. Pisarski, L. McLerran et al. W. Weise et al. + BR scaling (PRL 1991)

  6. HADES run statistics (phase 1) After upgrade in 2010: 100-200 TByte in 30 days • 6 runs between 2002 and 2008 • 1010 events taken • 100 days beam on target p+Nb FWq > 7o Ar+KCl 1.67GeV/u pp 1.25 GeV/uC+C 1 GeV/u pp 3.5 dp 1.25 GeV/u C+C 2 GeV/u Eur.Phys.J.A41:243-277,2009

  7. Dileptons from light collision systems

  8. Electron pairs from C+C collisions at 1 and 2 GeV/u e+ e+ e- e- e+ e- Phys. Lett. B 663(2008)43 Phys.Rev. Lett 98(2007) 052302 • Good normalization established in p0 region. • Evidence for yield above contributions from decays of long-lived hadrons. • What are the sources of contributions from the early phase? g* g* g*

  9. HADES data in the acceptance of DLS, compared to DLS data. The solution to the DLS puzzle? E. Bratkovskaya et al., PLB 2008. Modified description of Bremsstrahlung in HSD inspired by Kaptari et al.

  10. Dileptons from pp and np reactions at 1.25 GeV/u compared to HSD Data from HADES pp and dp (tagged n) at 1.25 GeV/u Cocktail from HSD calculation 2008 with revised description of Bremsstrahlung Data: HADES collaboration, arXiv:0910.5875 [nucl-ex]

  11. Electron pairs from C+C collisions compared to NN reference g* N N N N g* N N N*, Δ N N g* r N N N*, Δ HADES collaboration, arXiv:0910.5875 [nucl-ex] N N

  12. Dileptons from Ar+KCl at 1.76 GeV/u

  13. Electron pairs from Ar+KCl collisions at 1.76 GeV/u First observation of w mesons in HI collisions at these (SIS) energies Fit: exponential + gaussian 30-40 counts In peak! HADES collaboration, Nucl.Phys.A830:483C-486C,2009

  14. Excess radiation in Ar+KCl at 1.67 GeV/u N N N R N N R N p N R g* e- ...p N e+ Compared to reference after subtraction of contributions from h. • Indication for radiation from the medium. • Multistep processes or multi-particle correlation.

  15. Systematic of the excess yield Excess yield scales stronger than linear with Apart • Data for p0 and h from TAPS collaboration • Dilepton excess scales with beam energy like p production • C+C (DLS) • C+C (HADES) • Ca+Ca (DLS) • Ar+KCl (HADES)

  16. Refined HSD vacuum calculation • Enhanced bremsstrahlung from elastic NN collisions according to “Kaptari-Kämpfer” (OBE) prescription. • Reduced vector-meson production via the LUND string in order to better match pp exp. Data. • Improved isospin dependence of the channels NN-> V+NN and p+N-> V+N. “It’s a bingo” HSD, November 2009 release

  17. Dileptons from pp at 3.5 GeV Normalized to π peak preliminary preliminary K. Schmidt, et al. Phys. Rev. C 79, 064908 (2009) HSD, Nov. 09 release

  18. Dilepton production in pp at 3.5 GeV preliminary Particle production LUND string fragmentation Particle production through baryonic resonances

  19. Slope parameters in mass bins preliminary Mee = 0.35 – 0.50 0.50 – 0.65 >0.65 GeV Strong increase of slope parameter with increasing pair mass. No explanation yet.

  20. strangeness

  21. Strangeness production in 1.75 GeV/u Ar+KCl reactions K0s Λ High-statistics measurement of p+, p-, K+ and K-but also: K0s → p+p-L → p p-→K+K--→Lp- - HADES collaboration: Phys.Rev.Lett.103:132301,2009 Eur.Phys.J.A40:45-59,2009 Phys.Rev.C80:025209,2009

  22. HADES data and the SHM J.Cleymans priv. communication ■Ar+KCl at 1.76 GeV/u THERMUS fit S.Wheaton and J.Cleymans, J.Phys.G31(2005)S1069 T= 736 b=77043 (MeV) RC =2.4 0.8 fm Rfireball =4.9 1.4 fm 2=2.1 (no - ) • Particle multiplicities largely in accordance with SHM • f yield explained (non-strange particle ) • − underestimated by SM

  23. f/w-ratio M (→ K+K-): (2.6 ± 0.7) ·10-4 M (→ e+e-) : (6.7 ± 2.7) ·10-3 In accordance with SHM. No OZI suppression in the production.

  24. Multi-strange baryons Probability (Mss) to produce in Ar+KCl collisions a strange quark pair is ≈ 5 × 10-2. Bag fusion  quarkyonic matter? q q q q q q q q q q q q q q q q q q q q q q q q Strange quarks “trapped” in bubbles?

  25. The HADES upgrade … … from 8 X-/day (Ar+KCl) to 170 X-/day (Ag+Ag) and dilepton statistics like NA60

  26. The RPC time-of-flight system RPC D. Belver etal . NIM A602(2008) 687, 788 E. Blanco et al. NIM A602(2008) 691 • Full-system test results: • t  78 ps • x  8 mm • e~ 97% Leading institute: Coimbra, Portugal D. Belver etal . NIM A602(2008) 687, 788 E. Blanco et al. NIM A602(2008) 691

  27. HADES DAQ System Overview Fröhlich et al., IEEE Trans. Nucl.Sci. Vol. 55, Issue 1 (2008) 59 VME CPU MU RPC MDC CTS TOF VULOM3 Tothe Front End Electronics Shower RICH ... F. Wall Ethernet Start, Veto Average data rate 150 Mbyte/s. Trigger rate up to 20 KHz.

  28. Current proposal • 2010-2012 (2-3 campaigns). Main emphasis on: • Dielectron & strangeness production in heavy systems • low mass (0.15<Me+e- <0.5) excess studies • vector meson spectroscopy • /K production: differential distributions,y, pt (increased acceptance due to RPC !) , flow • - production characteristics • Two HI collision systems : medium size ,eg. Ag+Ag, and Au+Au at maximal beam energies of 1.65, 1.25 AGeV, respectively.

  29. The Future at FAIR SIS18 Upgraded HADES (20 kHz reaction rate) Au+Au and Ag+Ag, pion induced reactions from 2010 on. SIS100: Joint running of HADES and preCBM, multistrange particle and lepton pair excitation function, charm production in proton induced reactions SIS300: Full exploitation of rare probes a high mB; fluctuations, flow Mission: Systematics and sensitivity! Phase boundary and critical point.

  30. Towards FAIR

  31. The Quest for the highest densities Freeze-out configurations for HI collisions! Density in the centre of the collision zone J. Randrup and J. Cleymans, hep-ph/0607065 UrQMD

  32. The CBM detector • More than one million reactions / second (no trigger) • Fast high resolution tracking in a compact dipole field directly after the target • High speed DAQ and trigger • Excellent particle identification • Flexible arrangement of PID detectors and calorimeters:

  33. Dilepton production ...or from transport Thermal dilepton rate ... isentropic expansion In future: combine the best of the two worlds!

  34. Charm production • How are the produced charm quarks propagating in the dense phase, quark-like or (pre-) hadron-like? • Hidden over open charm as indicator (J/ψ, ψ', D0, D) • Charmed baryons important for a complete picture (c, Ξc) • Are there indicators of collectivity [HSD: O. Linnyk et al., Int.J.Mod.Phys.E17, 1367 (2008)] [SHM: A. Andronic et al., Phys. Lett. B 659 (2008) 149]

  35. Charm detection in CBM ~ 60 µm Si Diamond 300 µm < 200 µm Si ~ 60 µm Si < 320 µm Si • Challenge: • Find displaced decay vertex in an environment of hundreds of charged tracks • Event selection:real-time vertex finding in 20Gbyte/s • Needs vertex detector with: • High resolution • Minimal material budget • Radiation tolerance • Monolithic Active Pixel Sensors, also foreseen in ILC, STAR ct = 312 mm IMEC, Strasbourg, Frankfurt Factor 4-5 thinner than conventional solution

  36. Summary • „Long-lived“ states of dense nuclear matter are produced in collisions of heavy ion at energies of a few GeV/u. • The phase in the high-density region might be much more exotic then a hadron/resonance gas. • Unfortunately, there is no smoking gun, but: • Fast equillibration • „Sub-threshold“ production • Strong broadening of in-medium states • Close collaboration with, and novel approaches in theory are necessary to make the case.

  37. The HADES collaboration LIP-Laboratório de Instrumentação e Física Experimental de Partículas , 3004-516 Coimbra, Portugal Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland GSI Helmholtzzentrum für Schwerionenforschunm, 64291 Darmstadt, Germany Institut für Strahlenphysik, Forschungszentrum Dresden-Rossendorf, 01314 Dresden, Germany Joint Institute of Nuclear Research, 141980 Dubna, Russia Institut für Kernphysik, Johann Wolfgang Goethe-Universität, 60438 Frankfurt, Germany II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392 Giessen, Germany Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia Physik Department E12 & Excellence Cluster Universe, TUM, 85748 München, Germany Department of Physics, University of Cyprus, 1678 Nicosia, Cyprus Institut de Physique Nucléaire (UMR 8608), CNRS/IN2P3 - Université Paris Sud, F-91406 Orsay Cedex, France Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic Departamento de Física de Partículas, University of Santiago de Compostela, 15782 Santiago de C.a, Spain

  38. The CBM collaboration Univ. Frankfurt, IKF Univ. Frankfurt, Inst.Comp.Sc. Univ. Münster Univ. Wuppertal Hungaria: KFKI, Budapest Eötvös Univ. Budapest India: Aligarh Muslim Univ., Aligarh IOP, Bhubaneswar Panjab Univ., Chandigarh Gauhati Univ., Guwahati Univ. of Rajasthan, Jaipur Univ. of Jammu, Jammu IIT, Kharagpur SAHA, Kolkata Univ. of Calcutta, Kolkata VECC, Kolkata China: Tsinghua Univ., Beijing USTC, Hefei CCNU, Wuhan Croatia: University of Split RBI, Zagreb Czech Republic: Techn. Univ., Prague CAS, Rez France: IPHC Strasbourg Germany: GSI, Darmstadt FZ Dresden-Rossendorf Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Heidelberg, ZITI Univ. of Kashmir, Srinagar Banaras Hindu Univ., Varanasi Korea: Korea Univ. Seoul Pusan National Univ. Norway: University of Bergen Poland: Silesia Univ. Katowice AGH Univ. Krakow Jagiellonian Univ., Krakow Warsaw Univ. Portugal: LIP Coimbra Romania: NIPNE, Bucharest Bucharest University Russia: VBLHE, JINR, Dubna LIT, JINR, Dubna LPP, JINR, Dubna PNPI, Gatchina ITEP, Moscow MEPhI, Moscow Kurchatov Inst. Moscow SINP, Moscow State Univ. Obninsk State Univ. IHEP, Protvino KRI, St. Petersburg St. Petersburg Polytec. U. INR Troitzk Ukraine:INR, Kiev Shevchenko Univ. , Kiev Split, 2009 56 institutions> 400 members

  39. Thank you

  40. HADES data Exclusive electron pair production inpp collisions at 1.25 GeV Preliminary pppe+e-X Electron pair invariant missing mass (Mee) Three particle missing mass (MX) 200 events for Me+e- > 140 MeV/c2 Mee>140 MeV/c2 pp p+ppe+e- Mee(GeV/c2) MX(GeV/c2)

  41. HSD in-medium calculations

  42. Phi to omega ratio ... vector manifestation of hidden local symmetry ... to suggest that the dileptons measured in relativistic heavy-ion collisions do not provide direct information on the spontaneous breaking of chiral symmetry and hence on the mechanism for mass generation of light-quark hadrons.

  43. Systematics of slopes at 1.76 GeV/u π0 and η from TAPS Why are slopes of ρ/ω and  so different ?

  44. Trigger GEANT simulation with UrQMD events • HADES has a two level trigger system • LVL1 trigger • Multiplicity • 34% more central events of events • LVL2 trigger • at least one electron candidate 2.1× 109 triggered LVL1 events in the Ar+KCl run!

  45. Effenberger, Giessen

  46. Dileptons from pp and np reactions at 1.25 GeV/u p+p data: results from OBE (coherent sum of D and NN terms) seems to be too high (already D cross section is too high (factor 2-4), NN Bremsstrahlung also?) n+p data: not explained by theory, clear contribution of additional sources PLUTO: • D resonance: production: fixed to p0 by N(D) = 3/2 N(p0), decay: Krivoruchenko et al.,EM form-factor: QED, Krivoruchenko, GM=3, GE=GC=0 or VMD-like, Wan & Iachello, int. J. Mod. Phys. A20(2005) 1846 • h meson: constrained by CELSIUS/WASA data, H. Calén et al. PRC 58, 1998 • NN Bremsstrahlung: is currently implemented a-lá Kaptari and assuming isotropic emission HADES collaboration, arXiv:0910.5875 [nucl-ex]

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