1. 1 More information: http://www-hades.gsi.de zanevsky@lhedl.jinr.ru Status Report of HADES Project (JINR Participation) Theme: 03 - 1 - 1020 - 96/2005 Leaders: Yu. Zanevsky, A. Malakhov Participants: Yu. Troyan, G. Agakishiev, V. Belyaev, S. Chernenko, V. Chepurnov, O. Fateev, A. Ierusalomov, V. Pechenov, A. Troyan

2. 2 High Acceptance Di-Electron Spectrometer HADES detector is designed to provide an excellent mass-resolution (~1 %) and very large acceptance for comprehensive studies of the behavior of ,  and  - mesons in the nuclear medium. TOFINO Main Parts of HADES Spectrometer: Magnet SC toroid ( 6 coils)  in      Lepton Identification RICH C 4 F 10 + gas Phot. Det. CsI - cathode META TOF scintillator wall + Pre-Shower detector Tracking p – measurement vertex reconstruction MDC Drift chambers cell size  cm  x ~ 80  m (  ) Layout of HADES Spectrometer (Side View)

3. 3 The Collaboration includes 19 Institutions from 9 European countries Bratislava (SAS, PI) Catania (INFN - LNS) Clermont-Ferrand (Univ.) Cracow (Univ.) Darmstadt (GSI) Dresden (FZR) Dubna (JINR) Frankfurt (Univ.) Giessen (Univ.) Milano (INFN, Univ.) Moscow (ITEP, INR, MEPhI) Munich (Tech. Univ.) Nicosia (Univ.) Orsay (IPN) Rez (CAS, NPI) Sant. de Compostela (Univ.) Valencia (Univ.) HADES Collaboration HADES Setup

4. 4 3D sketch of the HADES spectrometer, split along the longitudinal direction for clarity. In operating conditions all the shown elements fit into each other making the whole structure much more compact. H igh Acceptance D i- E lectron S pectrometer

5. 5 R&D and Prototyping of full-size multilayer Drift Chamber; Development and testing of Front End Electronics for Drift Chambers System; Development and construction of inner low mass Multilayer Drift Chambers (6 modules, plane II); testing and integrating into the HADES spectrometer; Development of Track reconstruction software ( It was developed and successfully applied for commissioning of HADES spectrometer and for data analysis as ‘ Dubna Tracking Software ’ ); Participation in physical program and data analysis. Main tasks of JINR activity for HADES HADES Spectrometer in 2003

6. 6 Full-size Drift Chambers Prototype Assembling of Prototype at JINRTesting of Prototype on the beam at GSI The Prototype [1] consists of 13 wires layer - 6 anode and 7 cathode planes. All anode planes have different orientation (± 40º, ± 20º, ± 0º) to avoid multihit unambigiously. Sense wire pitch is 6 mm ( 20 mkm, Au/W). Cathode and Field wires have diameter 80 mkm ( Al). Anode- Cathode distance is 2,5 mm. Total number of channels is ~1200. Windows made from Al-mylar, 12 mkm. Operating gas mixture – He/Isobutan (60/40). The frame is very narrow – 35 mm. The results of the tests in laboratory and on the beam at GSI are very successful. We have got a high spatial resolution (~ 70 μm) and high efficiency. The Chamber had a long term stable operation.

7. 7 Front End Electronics for HADES Drift Chambers The last test of Front End Electronics before installation into Magnet Very important parts - flat cables with 16-channels Ampl/Discr. Cards Front End Electronics [4] for HADES Drift Chambers has been developed (R&D) and tested by JINR team. 16- channels Card of Ampl / Discr. was designed on the base of ASD-8 chip with the rise time ~ 15 ns and fall time ~30 ns. Power dissipation per channel is less than 35 mW. Total number of channels is about 26 000. During 4 years running in cosmic rays tests and beamtimes only 1 broken channel was found. Very important parts – flat cables- have been designed in collaboration with GSI team ( to connect 16 –channels Ampl/Discr. cards to Drift Chambers).

8. 8 Drift Chambers - assembling and installation 6 modules of Multilayer Drift Chambers (plane II) were constructed and successfully tested in Dubna. After the assembling and testing in HADES cave this Drift Chambers have been installed into the Magnet and Commissioning started [5-7]. The efficiency of the Chambers was better than 98% in environment of high multiplicity, spatial resolution - about 100 mkm, plateau - ~ 200 v. Assembling of Drift Chambers in HADES cave Installation of Drift Chambers, plane II into the Magnet

9. 9 Spatial resolution of HADES Drift Chambers Spatial resolution of Drift Chambers ( planes I - IV) From the Report on Vienna Instrumentation Conference, Febr. 2004 [7] Planes I – IV of HADES Drift Chambers

10. 10 Track reconstruction software for HADES ( Dubna Tracking Software ) Multihit event in Drift Chamber, plane II [3].Track fitting performed only with 1 Drift Chamber Plane II (with several sense planes) [3].

11. 11 Online vertex reconstruction (Nov02 data) 2 carbon discs were used as the target (diameter 8mm, distance between them ~20 mm)

12. 12 1.Simulation of pp interactions at various energies (including electromagnetic decays of hadrons). 2.Track reconstruction and momentum determination software. 3.On-line and off-line vertex reconstruction, monitoring of drift chambers data quality. 4.Participation in the commissioning, HADES experimental program and data analysis: C+C (1.5-2.0 AGeV) p+p (1.5-2.2 GeV) Ca + Ca (1,5 AGev) 5.Installation in LHE JINR of LINUX cluster with the HADES software for simulation and data analysis. 6.Participation in development of Drift Chamber’s ALIGNMENT software. The work is supported by INTAS and JINR/BMBF grants Main items of JINR activity for HADES project (2002-2005 )

13. 13 DETECTOR STATUS From P. Salabura report on PAC / GSI, September 2004 The experiment is now successfully commissioned and first physics data was taken with carbon and proton beams.

14. 14 Data Analysis and Experimental Program -During the production beamtimes of 2002 - 2004 were collected : ~ 210 mio events C+C@ 2,2 AGev (2002) ~ 500 mio events C+C@ 1,0 AGev (2004) ~ 400 mio events p+p@ 1-2,5 Gev (2004) Data analysis is in progress -Due to the installation of outer Drift Chambers the Δ P / P is improved up to 1,5% -Further physical program on SIS and on future accelerator facility FAIR (A + A at 2-8 AGev) is under development. HADES has shown that the data is at least of simular quality to data taken by DLS or CERES. Nearest Physical Program 1. Dielectrons from pp/pd 2. On threshold η production in d+p 3. ω production in pp collisions 4. Dielectrons from Ca+Ca (84 shifts of this beam will be used in 2005). Proposal from JINR: the search and study of low-mass scalar σº meson in the reaction pp→ppσº with the decay of mesons through modes σº→2e+ 2e¯ and σº→e+ e¯ ץ. The results will be discussed on the next HADES Collaboration Meeting in Dubna, 7-12 June 2005.

15. 15 Momenta Resolution with 1, 2, 3 and 4 Drift Chambers planes Resolution [%] p

16. 16 Preliminary First Results: Dielectrons, Vector Mesons Simulation: Ca+Ca@ 2.2 AGev ΔP/P is improved up to ~ 1,5 %. with outer Drift Chambers were installed now in HADES Spectrometer. Experimental data: C+C @ 2.2AGeV Nov’2002 Spectrum of effective mass of e+ e¯ pair (red color). There is a good agreement with simulation. Without outer Drift Chambers (ΔP/P is ~ 8%) M [GeV/c ² ]

17. 17 List of publications where the JINR participants are also the principal authors: 1. C.Garabatos et al. “Optimisation of low-mass drift chambers for HADES”, NIM A412 (1998) 38 2.F.Dohrmann et al. “A Low-Mass Drift Chamber System for the HADES Spectrometer”, Acta Phys. Polonica B29 (1998) 3189 3. G.Agakishiev et al. “Development and Investigations of Low - Mass Multilayer Drift Chambers (MDC-2) for the Inner Part of the HADES Spectrometer, JINR Rapid Communications 5-99, (1999) 4. S.Chernenko et al. “Development and Design of Analogue Read-Out Electronics for HADES Drift Chamber System”, Particles and Nuclei, Letters No.1[98] (2000)73 5. H. Bokemayer et al.”Development of low-mass drift chambers for the HADES Spectrometer”, NIM A477 (2002) 397 6. F. Dohrman et al.”The HADES tracking system: First in-beam experience”, IEEE Trans. Nuc. Sci. vol. 51, no. 3, June (2004)939 7. C.Muentz et al. “The HADES tracking system”, NIM A535 (2004) 242 8. G.Agakichiev et. al ”.Study of e+,e- production in elementary and nuclear collisions near production threshold with HADES”, Progress in Particle and Nuclear Physics, Vol53 (2004) 49 9. P.Salabura et al. ”Dielectron Spectrometry with HADES”, Nuclear Physics News v.14, n.3 (2004) 27 10. G.Agakichiev et al. ”Studying in medium hadron properties with HADES”, Acta Phys. Polonica, vol.35 No.3 (2004) 1119 11. G. Agakichiev et al. “ Particle identification with HADES”, Nuclear Physics A 734 (2004)78 Main Publications

18. 18 Main Items of JINR activity in 2006 - 2008 1.Maintenance of Drift Chambers and Front End Electronics. 2.Participation in beamtimes. 3.Further development of Tracking Software (including Alignment). 4. Participation in development of physical program and in data analysis.

19. 19 Resources required in 2006-2008 2006 2007 2008 Computing 5 k$ 4 k$ Participation in beamtimes and meetings 25 k$ 26 k$ Total: 90 k$

20. 20 The HADES spectrometer offers a unique possibility for systematic studies of the light vector meson mass distributions inside nuclear matter by means of di-electron spectroscopy. Recent results from commissioning runs confirmed the expected superior on-line and off-line electron identification capabilities. In particular, a high-statistics run with LVL2 trigger provided first pair data from C+C reactions at 2 AGeV. High resolution di-electron spectroscopy becomes now also possible, after the completion of the outer MDC tracking system. The full experimental program is planned for several years. First experiments aiming at the exclusive meson reconstruction in proton-proton reactions have been started in 2004. High resolution studies of the vector meson production in pion induced reactions and light nucleus-nucleus system are planned in next 2-3 years. The HADES experimental program for FAIR (2-8 AGev) is under development. The JINR’s activity for HADES project was highly appreciated in Recommendations of JINR/BMBF Committee and in Summary of 5 th Workshop on the Scientific Cooperation between German Research Centers and JINR (17-19 January 2005, Dubna). We apply to JINR PAC to prolong theme 1020 on 2006-2008 with the first priority. CONCLUSIONS

21. 21 HADES CBM The nuclear reaction experiments at the future facility at GSI A+A at 2-8 AGeV A+A at 8-40 AGeV