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DEAR eXperiment D A F NE E XOTIC A TOMS R ESEARCH

DEAR eXperiment D A F NE E XOTIC A TOMS R ESEARCH. LNF SPRING SCHOOL “Bruno Touschek” In Nuclear, Subnuclear and Astroparticle Physics M.Iliescu, May 22, 2003 Frascati (Italy). M. Augsburger j , G. Beer b , S.Bianco c , A.M. Bragadireanu c,i ,

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DEAR eXperiment D A F NE E XOTIC A TOMS R ESEARCH

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  1. DEAR eXperiment DAF NE EXOTIC ATOMS RESEARCH LNF SPRING SCHOOL “Bruno Touschek” In Nuclear, Subnuclear and Astroparticle Physics M.Iliescu, May 22, 2003 Frascati (Italy)

  2. M. Augsburgerj, G. Beerb, S.Biancoc, A.M. Bragadireanuc,i, M. Bregantd, W.H. Breunlicha, M. Cargnellia, D. Chatellardj, J.-P. Eggerk, F.L. Fabbric, B. Gartnera, C. Guaraldoc, R.S. Hayanof, M. Iliescuc,i, T. Ishiwatarie, K.Itahashie, T.M. Itol, M. Iwasakie, R. Kinga, P. Knowlesj, T. Koikeh, B. Laussc,a, V. Lucherinic, L. Ludhovaa, J. Martona, E. Milottid, F. Mulhauserj, S.N. Nakamurag, C. Petrascuc,i, T. Pontai, A.C. Sandersonb, L.A. Schallerj, L. Schellenbergj, H. Schneuwlyj, R. Sekil,m, D. Sirghic,i, F. Sirghic,i D. Tomonoe, T. Yoneyamae, E. Zavattinid, J. Zmeskala a Institute for Medium Energy Physics, Austrian Academy of Sciences, Austriab Univ. of Victoria, Dept. of Physics and Astronomy, Canadac Laboratori Nazionali di Frascati dell'INFN, Italyd Univ. degli Studi di Trieste, Dip. di Fisica and INFN Sezione di Trieste, Italye Tokyo Institute of Technology, Japanf Univ. of Tokyo, Dept. of. Physics, Japang Inst. of Physical and Chemical Research (RIKEN), Japanh KEK, High Energy Accelerator Research Organization, Japani Inst. of Physics and Nuclear Engineering - " Horia Hulubei ", Romaniaj Univ. de Fribourg, Inst. de Physique, Switzerlandk Univ. de Neuchâtel, Inst. de Physique, Switzerlandl W.K.Kellogg Radiation Laboratory, Californiam Department of Physics and Astrophysics, California State University The DEAR Collaboration

  3. The determination of the isospin dependent KN scattering lengths through a few percent measurement of the shift and the width of the Ka line of kaonic hydrogen and the first measurement of kaonic deuterium The objective of DEAR (Deser - Trueman)

  4. The implications of DEAR results A measurement of KN scattering lengths at the percent level would enable the determination of the KN sigma terms with a precision of about 20% or less, to be compared with the 70% uncertainty of the present estimates. Sigma terms are directly connected with the chiralsymmetry breaking part of the strong interaction Hamiltonian. Also, the fraction of strangeness content in proton can be derived with better accuracy from KN and pN sigma terms (Jaffe ‘87)

  5. n 4 3 2 1 s p d f Kb  K46keV }  What DEAR measures Kaonic Hydrogen cascade Strong Interaction causes:  energy shift  compared to pure Coulomb interaction level width  due to the short lifetime caused by Kaon capture

  6. A5 A3 A6 A4 A7 A1 A2 A8 K- D1 D8 e+ e- D2 IP D7 K+ D3 D6 D4 D5 CCD-55 detectors positioning in the cryogenic setup

  7. g X-ray Charged particle Substrate Active depletion (30mm) How DEAR measures KH transitions: X-ray spectroscopic CCDs Charge-Coupled Devices are solid state detectors with a pixel structure. They are excellent detectors for soft X rays in the high background environment of a collider, for the powerful rejection capability (given by the topology of X-ray events -single pixels-), together with a very good energy resolution, high efficiency and large active area. Background suppression by single pixel selection

  8. Target and cryogenic setup layout

  9. Fiber-glass reinforced kapton target Operating conditions: 20 K, 3 bar (~40 bar NTP)

  10. CCD mounting, cryogenics and on-cell electronics Requirements: high compaction to allow optimal shielding and light materials to reduce Bremsstrahlung - fiberglass frames - cooling system mounted on the top - thin Al cold finger - reduced diameter of the socket group and, consequently, of the vacuum chamber

  11. DEAR shielding Pb walls Target Vacuum jacket shielding Pb platform e+ e- Interaction point Pb collimators Overall shielding factor of the DEAR interaction region ~ 100

  12. DAQ performance -Resolution and L.N. characteristics: · thermal noise FWHM of about 15 eV · energy resolution at 5.9 keV (Mn Ka line) 136 eV, charge transport correction not applied -Linearity: ~ 10-4 -Instability: below 4 eV/month -Charge transport inefficiency: ~10-6 -Synchronous readout of 16 large area detectors (CCD55-30) -Data flow 32¸64 MB/sec -Dual bus real-time system equipped with N.I. boards -Injection synchronization -Software dual slope integration

  13. 1000 Constant Scattering Length K-Matrix Potential Model Cloudy Bag Model Consituent Quark Model 800 600 Width (eV) [ G ] Izycki et al, 1980 400 200 Bird et al, 1983 0 Davies et al, 1979 -500 0 500 Shift (eV) [ e ] State of art of Kaonic Hydrogen measurement and theoretical predictions DEAR preliminary result Iwasaki et al, 1997 KpX

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