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Probing resonance matter with HADES „” „EMMI Workshop and XXVI Max Born Symposium” Wrocław 9-11.07.2009 Wrocław 9-11.07.2009 P. Salabura Jagiellonian University/GSI for the HADES collaboration
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Baryonic matter at 1-2 AGeV Au+Au moderate densities but long system life time Baryonic matter: / N = 1-3, T< 80 MeV, ~15 fm/c nucleons, baryonic resonances (~30%) 33, mesons(π 0 )~10% “resonance matter” What is still (after >20 years) exciting in this field ?? e.m radiation from „resonance matter” – excess connection to / in-medium properties ? Sub-threshold strangeness production: , K + K -, - (1321) ~10fm/c Composition of a barionic matter Rear probes: dielectrons & strangeness HADES
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Dielectrons from C+C @ 1.0 GeV DLS Data: Phys.Rev.Lett. 79 (1997) 1229 HADES : Phys. Lett. B 663 (2008) 43 HADES data projected into DLS acceptance Very good agreement between 2 experiments full confirmation of DLS effect DLS Data & Transport (1999) : W. Cassing, E.L. Bratkovskaya Physics Reports 308 (1999) 65 Excess ?? above what? do we have a good reference ? .. frankly speaking, no! elementary e+e- sources not fully known E.L. Bratkovskaya and W. Cassing NPA 807, 214 (2008) & new. N-N bremss.OBE Kaptari & Kämpfer NPA 764 (2006) 338 2008
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Reference: dielectrons from pp and “quasi-free” pn @ 1.25 AGeV pp/pn data are not described by recent OBE calculations ! 12 Model Calculations: a) NN NNe+e- OBE calculations Kaptari & Kämpfer (K&K) NPA 764 (2006) 338 b) , yield constraint by data. Dalitz decay Krivoruchenko et al. Phys. Rev. D 65 (2001) 017502 + VMD form- factor (Q. Wan and F. Iachello, Int. J. Mod. Phys. A 20 (2005) 1846)
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Excess or no excess ? C+C data reproduced (within 20%) by superposition of NN interactions (reference) & scaling with pion production Larger system size – Ar+KCl (4 larger A part )-first evidence for the in-medium effect – baryonic radiation : i.e N N N N .. ( fireball ~10x ) ! Different mechanism as at SPS ( pion annihilation) preliminary F ~ 3
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Vector mesons / at SIS p+p at 3.5 GeV 2005 40 Ar+ 38 KCl 1.75 AGeVp+ 92 Nb 3.5 GeV 2008 “on-line spectrum!” Systematic studies on / production at SIS has been started Verification of p+A from KEK (advantage lower beam energy ) & CBTAPS/CLAS Only consistent description of the pp/p+A/and A+A can give full picture M () 15 MeV/c 2 preliminary
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K + K - / - production at SIS via ? Strangeness Exchange : belived to be dominant non-resonant resonant ( ->K + K - ) 19 sub-threshold, OZI suppressed ? - (1321) S=- 2 deep subthreshold (~600 MeV) not measured Strangeness Exchange + network of reactions sensitvity to EOS A.Andronic, P. Braun-Munzinger, B. K. Redlich, NPA 765 (2006) SIS?
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/ Production in ArKCl @ 1.75AGeV / Production in ArKCl @ 1.75AGeV / ~1 fixed to pp data, yield in line with m T scal. R( / ) = 4.2*10 -3 *f OZI rules for N-N enhanced R( / ) in HI as compared to N-N( ) close to stat. model (THERMUS) !(no suppression) different absorption? M =1017,8 ± 0.9 MeV/c 2 = 6.2 MeV/c 2 e+e- e+e- =23 6 MeV OZI preliminary S. Wheaton and J. Cleymans, hep-ph/0407174
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/ K - ratio Statistical model K. Redlich, H. Oeschler-priv.comm T eff =69 3 T eff =89 4 /K - =0.34 0.13 & is enhanced is important source of K - in HI collisions at SIS HADES: accepted PRC: arXiv:0902.3487 T eff =84 8
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- production in Ar+KCl @ 1.75 AGeV 23.01.2009 P.Salabura identification: HADES data THERMUS fit S. Wheaton and J. Cleymans, hep-ph/0407174 ? T= 70 3 b =746 15 (MeV) R C =2.6 0.4 fm R fireball =6 0.7 fm 2 =2.1 (no - ) preliminary
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23.01.2009 Outlook: future exp. Upgrade RPC, DAQ, MDC1, EM Calorimeter (for SIS100) 2008/9/10 Hades goes to FAIR ( 8 AGeV) > 2013 (SIS100) 2011 + N, + A resonance ( , N * ) radiative decays, strangeness 2010 Ag +Ag @ Au+Au dielectrons ( / ), strangeness (K - K + . , ) 2009-2011SIS18 increase of Mul( / ) by 2 orders of magnitue !! CBM HADES
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23.01.2009P.Salaura12 The Collaboration GSI SIS Catania (INFN - LNS), Italy Cracow (Univ.), Poland Darmstadt (GSI), Germany Dresden (FZD), Germany Dubna (JINR), Russia Frankfurt (Univ.), Germany Giessen (Univ.), Germany Milano (INFN, Univ.), Italy München (TUM), Germany Moscow (ITEP,MEPhI,RAS), Russia Nicosia (Univ.), Cyprus Orsay (IPN), France Rez (CAS, NPI), Czech Rep. Sant. de Compostela (Univ.), Spain Valencia (Univ.), Spain Coimbra (Univ.), LIP, Portugal
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23.01.2009P.Salabura BACK-UP SLIDES Conference
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Side View START FW 3 High Acceptance Di-Electron Spectrometer Beams from SIS18: pions, protons, nuclei high invariant mass resolution (2% at / mass) and powerful PID capabilities : p/π/K/e Large acceptance for sys. studies : dielectrons (e+,e-) strangeness: K ,0, , , Geometry Full azimuth, polar angles 18 - 85 e+e- pair acceptance 0.35 ~ 80.000 channels, segmented solid or LH 2 targets 1 m P.Salabura
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23.01.2009P.Salabura N-N Bremsstrahlung E.L. Bratkovskaya and W. Cassing arXiv:0712.0635v1 NN ("quasielastic")-non resonant Strong + electromagnetic process (OBE models) 1 2 e+ e- + = resonant -baryon resonances ( ) 1 2 + collection of results from E.L Bratkovskaya & W. Cassing: Nucl.Phys A 807, 214 (2008). bremsstrahlung OBE calculations: Kaptari & Kämpfer, NPA 764 (2006) 338: K&K OBE calculation: pn bremsstrahlung 4 larger (simplified picture!) 10
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16 e+e- Invariant mass spectrum decomposition e+e- decays Mesons (known) Baryon resonances (not measured !) – important at lower beam energies SIS18 Two-body decays (known) : e+ e- e+ e- e+ e- Example cocktail HADES data p+p @ 3.5 GeV compared to model calc. pp @3.5 GeV 00 // 23.01.2009P.Salabura
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23.01.2009P.Salabura DLS Vector mesons: pairs from DLS Data: Calculations: C.Ernst et alPhys. Rev. C58 (1998) signal not visible due to resolution enhancement below / pole – resonance radiation ? Coupling of to N * (1520), N * (1700) ? Coupling of to N*(1535) ? Relevant for in-medium : extended VDM Ch. Fuchs Phys. Rev. C68 (2003) 014904 Conference
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Invariant Mass Spectra of 23.01.2009ConferenceP.Salabura
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K0-Nucleon Potential Kaon-Nucleon Potential: 30 MeV @ = 0 (HADES and IQMD) C. Hartnack, J. Aichelin, H. Oeschler Results from FOPI (HSD) KN-Potential is repulsive with a strength of U=20 MeV 23.01.2009ConferenceP.Salabura
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20 p+p @ 1.25 GeV - Dalitz decay Dalitz decay e+e+ ++ e--e-- p e--e-- Time-like - N transition branching ratio BR(M) ? EM-formfactors (G M, G E, G C ) ? q 2 = M 2 inv (e + e - ) = M * 2 > 0 ** grey band Iachello. VMD QED PLUTO calculations : a) NN-bremsstrahlung Kaptari & Kämpfer (K&K) b) Dalitz decay Krivoruchenko et al. Phys. Rev. D 65 (2001) 017502 + VMD form-factor (Q. Wan and F. Iachello, Int. J. Mod. Phys. A 20 (2005) 1846) PRELIMINARY VMD 23.01.2009P.Salabura
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21 d+p p spec e+e-X @ 1.25 AGeV – „quasifree” p-n collisions selection of np reactions via spectator proton in Forward Wall spectator "tag" Mult. 1 FW (0.5 –7 ) cocktail: a) np-Bremsstrahlung a-la Kaptari & Kämpfer, and (constrained by data) b) Fermi momentum of nucleon in deuterium from N-N Bonn potential neutron „target” proton proton neutron e + e – PRELIMINARY p spec pcpc No satisfactory description of pp and pn data!! 23.01.2009P.Salabura
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22 log. z axis ! e-e- e+e+ hadron : lepton suppression ~10 -4 Particle IDentification e-e-e-e- e+e+e+e+ M inv = p1p1 p2p2 Target RICH HADRONS Momentum vs velocity (β) dE/dx in MDC & TOF LEPTONS (RICH tagging) Kaon identification 23.01.2009P.Salabura
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