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Final Results of the DEAR Experiment and Future Plans at the SIDDHARTA Experiment

Final Results of the DEAR Experiment and Future Plans at the SIDDHARTA Experiment. T. Ishiwatari, Stefan Meyer Institut für subatomare Physik, Austrian Academy of Sciences, Vienna, Austria On behalf of the DEAR and SIDDHARTA Collaborations. LNF SMI INFN Trieste Univ. Fribourg

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Final Results of the DEAR Experiment and Future Plans at the SIDDHARTA Experiment

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  1. Final Results of the DEAR Experiment and Future Plans at the SIDDHARTA Experiment T. Ishiwatari, Stefan Meyer Institut für subatomare Physik, Austrian Academy of Sciences, Vienna, Austria On behalfof the DEAR and SIDDHARTA Collaborations LNF SMI INFN Trieste Univ. Fribourg Univ. Neuchâtel RIKEN Univ. Tokyo Univ. Victoria T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  2. The results of the DEAR experiment Kaonic nitrogen X-ray yields at r=3.4 rNTP 7-6: 33.7 ± 8.1 (sta) ± 3.4 (sys)% 6-5: 55.5 ± 4.2 (sta) ± 5.5 (sys)% 5-4: 64.4 ± 15.6 (sta) ± 6.4 (sys)% PLB593(2004)48 Kaonic hydrogen Ka line Shift: 1s = - 194 ± 37 (sta) ± 6 (sys) eV (replusive) Width: 1s = 249 ± 111 (sta) ± 30 (sys) eV Acta Physica Slovaca 55(2005)69, Submitted to PRL T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  3. Motivation • The shift ε1s and width Γ1sin the 1s state both of kaonic hydrogen and deuterium • Determination of isospin independent KN scattering lengths requires data both kaonic hydrogen and deuterium • a0and a1 are important for L(1405), deeply-bound kaon states, S0(3115), KN s-term, SU(3) chiral symmetry… S. Bianco et al., Rev. Nuovo. Cimento 22 (1999) 1. T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  4. Kaonic hydrogen puzzle Stark effect KpX (KEK) M. Iwasaki et al, 1997 DEAR G1s • = - 323 ± 63 ± 11 eV G = 407 ± 208 ± 100 eV E1s e1s } -500 0 500 repulsive attractive f s p d 1000 800 E2p Izycki et al, 1980 600 widthG1s[eV] 400 200 Bird et al, 1983 Davies et al, 1979 0 shifte1s[eV] T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  5. K-p and K-d atoms high background 0.Kaonic nitrogen X-ray lines at high n transition *A.N. Ivanov et al., EPJA23(2005)79 • Kaonic hydrogen Ka • 2. Kaonic deuterium Ka T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  6. Impact on kaonic nitrogen X-ray measurement High-density e- N The most precise values have a 60 keV difference mK=493.696±0.007 MeV (K-C: Denisov 91) mK=493.636±0.011 MeV (K-Pb: Gall 88) The charged kaon mass mK=493.677 ±0.016 MeV (PDG) A new kaon mass measurement is proposed using a nitrogen gas. PLB 535 (2004) 52 Electron screening effect must be studied Low density K N PDG, PLB (2004)1 T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  7. DAΦNE (LN Frascati) APD Cryo-Cooler TMP CryoTiger CCD Cooling CCD Electronics DEAR Vacuum Chamber CCD Pre-Amplifier Target Cell CCD55-Chips electron – positron collider optimuzed to produce Φ-meson at rest (1.020 GeV) kaons from Φ decay T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  8. DEAR experimental setup Shielding reduces background a factor~ 100 T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  9. Experimental Setup APD Cryo-Cooler TMP CryoTiger CCD Cooling CCD Electronics Vacuum Chamber CCD Pre-Amplifier CCD55-Chips kaons from Φ decay e+ e- T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  10. DAFNE Luminosity Kaon Monitor Φ production cross section ~ 3000nb (corrected for radiative losses) Integrated luminosity ~ 2pb-1 per day  ~ 3 × 106 K- per day kaons are directly measured by the scintillators. T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  11. CCD Detector • 16 CCD55-30 chips are used • 1242 x 1152 pixels • pixel size 22.5 x 22.5 µm • total area per chip 7.24 cm2 • depletion depth ~30 µm • read-out time 2 min. • energy resolution ~150 eV @ 6keV • temperature stabilized at 165 K T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  12. CCD Pixel analysis X-ray events  single and double pixel events Charged particles  large-sized events background suppression by pixel analysis T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  13. X-ray events Selecting single- and double-pixel events as X-rays gives excellent background rejection T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  14. Experimental Data Kaonic Nitrogen April: 3.-29.4.2002: ~9000 × 16 files (160GB) 14.2 pb-1 => 20.5 × 106 K- Kaonic Nitrogen October: 6.-28.10.2002: ~7000 × 16 files (112GB) 17.4 pb-1 => 25.1 × 106 K- Kaonic Hydrogen: 30.10.-16.12.2002: ~18000 × 16 files (288GB) 58.4 pb-1 => 84.1 × 106 K- Hydrogen, no collisions: 16.-23.12.2002: ~2600 × 16 files (42GB) No kaons. Removed scrapers to produce high background T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  15. Kaonic Nitrogen X-ray Spectrum Kaonic nitrogen lines of the 7-6, 6-5, and 5-4 transitions are observed. The 7-6 and 5-4 transitions are overlapped with the Ti and Sr lines, respectively. 10.8 pb-1 Si Al Ca The number of each X-ray peaks are obtained by the fit. Zr Efficiencies for kaons to stop the target, and for X-rays to be detected by the CCDs are estimated by the Monte Carlo. T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  16. Results of kaonic nitrogen Future measurement will allow to solve this problem • Three squential X-ray lines from kaonic nitrogen atoms in a gaseous target • The transition yields for 7-6, 6-5, 5-4 are obtained as: • Kaonic nitrogen is a highly ionized system. Kaonic nitrogen has electrons with a few %. • high precision measurement of the charged kaon mass possible • Kaon mass (test) mK- = 493.884 ± 0.314 MeV ΔmK- = 60 keV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  17. Kaonic Hydrogen n 4 3 2 Fe Ka = 6.4 keV 1 Y(KH) ~ 1-3% S/N~1:100 The yield of kaonic hydrogen is small, and the energy is close to Fe Ka. s p d f Negligible shift and width in the n>1 states E2p Kg G1s Ka ~ 6.3 keV E1s e1s } T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  18. Kaonic Hydrogen X-ray spectrum Raw spectrum (background fitted with cubic function) T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  19. Experimental Data Kaonic Nitrogen April: 3.-29.4.2002: ~ 9000 × 16 files (160GB) 14.2 pb-1 => 20.5 × 106 K- Kaonic Nitrogen October: 6.-28.10.2002: ~ 7000 × 16 files (112GB) 17.4 pb-1 => 25.1 × 106 K- Kaonic Hydrogen: 30.10.-16.12.2002: ~ 18000 × 16 files (288GB) 58.4 pb-1 => 84.1 × 106 K- Hydrogen, no collisions: 16.-23.12.2002: ~2600 × 16 files (42GB) Background measurement without crossing beams at the IP T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  20. Countinuous background shapes are subtracted. Background subtracted spectra • Two spectra are normailized. • Intensity of Fe Ka line • from background data • Energy difference of K-lines • are fixed. • Same Lorenzian width • for the K-lines • Relative yields for Kg,Khigh ... • are examined • Stability tests for the fits • with several fit ranges T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  21. Kaonic hydrogen X-ray spectrum X-ray energy spectrum with subtraction of all the background components • Repulsive shift • Ka, Kb and Kg are clearly disentangled, for the first time • With small errors Shift: 1s = - 193 ± 37 (stat.) ± 6 (syst.) eV Width: 1s = 249 ± 111 (stat.) ± 30 (syst.) eV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  22. Results of kaonic hydrogen 1000 800 DEAR 600 Izycki et al, 1980 400 1s = - 193 ± 37 (stat.) ± 6 (syst.) eV 1s = 249 ± 111 (stat.) ± 30 (syst.) eV aK-p = - 0.466 ± 0.104 + i 0.299 ± 0.174 fm 200 Bird et al, 1983 Davies et al, 1979 0 -500 0 500 shifte1s[eV] attractive repulsive KpX (KEK) M. Iwasaki et al, 1997 KpX widthG1s[eV] • = - 323 ± 63 ± 11 eV G = 407 ± 208 ± 100 eV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  23. The SIDDHARTA project - experimental study of kaonic deuterium and helium Silicon Drift Detector for Hadronic Atom Research and Timing Applications Development of a triggered soft X-ray detection system, based on Silicon Drift Detectors (SDD), with high energy resolution and high background reduction for applications in exotic atom research T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  24. Kaon – X-ray coincidence e+ K+ F K- Φ K+ + K- X-ray e- S/N =1:1005:1 for kaonic Hydrogen Triple coincidence: SDDX * ScintK * ScintK Scintillator SDD D2 gas Scintillator An improvement of the S/ N of ~ 2 – 3 orders of magnitude T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  25. SDD design for SIDDHARTA chip size: 34 x 14 mm² sensitive area 3 x 100 mm² integrated temperature sensors T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  26. Possible SDD and target setups New design for triggered target-detector system Large area SDDs (1cm2 each, total area ~ 200 cm2) (2) Conventional topology (1) toroidal topology SDDs SDDs e+ R e- e- Cryogenic gas target volume Scintillators e+ L With 200 cm2 SDDs, only part of the cylindrical surface can be covered Trigger scintillators not shown T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  27. Kaonic deuterium (Monte Carlo) Background suppression to > 103 Kaonic deuterium Ag K fluorescence lines (calibration) Ka Kb,g De= 15 eV DG=35 eV S/B=1:1 SDD w/o coinc. MIPs (e+/e-) in SDD Kaon decays coinc. SDD * Scint * Scint Energy (keV) Energy (keV) Width G1s ~ 630 eV Shift e1s ~ 330 eV A.N. Ivanov et al., EPJA23(2005)79 Yield Y(Ka) ~ 0.2% Signal rate ~ 2.2x10-3 /s 130 /d (duty cycle=2/3 of d.) T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  28. Kaonic Helium-4 Puzzle (large shift and width in 2p state) Kaonic helium puzzle Abnormal shift and large uncertainty in width In the kaonic 4He 2p state E (Fe Ka1) = 6.4038 keV E(exp)-E(Fe)= ~10 eV Assuming a deeply bound kaon state exists (YA02 model) T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  29. Summary The results of kaonic hydrogen are • Repulsive shift of the Ka line is verified. • Most accurate determination of the shift and width. • Kβ, Kγ lines are disentangled for the first time. • The results of kaonic nitrogen are • 3 sequential X-rays was measured • Yields of kaonic nitrogen at a gas target was obtained • Kaonic nitrogen is highly ionized • Kaon mass can be obtained T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  30. Outlook • Large area SDDs -- trigger capability (SIDDHARTA) • New target and detector system in progress New experiments – exciting physics • First measurement of kaonic deuterium • Much precise measurement of kaonic hydrogen. • Further perspectives:kaonic helium (He-3, He-4). Precision measurement of chargedkaon mass. SIDDHARTA Silicon Drift Detectors for Hadronic Atom Research by Timing Applications T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  31. News on exotic atomsInternational Conferenceon Exotic Atoms, EXA05February 21 – 25, 2005Viennawww.oeaw.ac.at/smi/exa05 T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  32. Kaonic Hydrogen Data Analysis • Kaonic hydrogen spectrum • “no collision” spectrum • Kaonic nitrogen spectrum as Signal data as Background data • Determination of background shape • Finding all the fluorescence X-ray peaks • subtractionof the continuous background and fluorescence X-ray lines T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  33. SDD structure SDD with integrated JFET Detector produced at the MPI Halbleiterlabor, Munich, Germany T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  34. Exp. = liq. 4He No experiment of 3He E (K He La) = 6.464 keV E (Fe Ka1) = 6.4038 keV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  35. Kaonic helium puzzle E 2p (K He) = 6.464 keV E (Fe Ka1) = 6.4038 keV Assuming a deeply bound kaon state exists (YA02 model) T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  36. Energies & yields of K-He L lines (Baird) E (Fe Ka1) = 6.4038 keV E(exp)-E(Fe)= ~10 eV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  37. Kaonic He L X-ray yields (Koike) T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  38. T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

  39. Exp. = liq. 4He No experiment of 3He E (K He La) = 6.464 keV E (Fe Ka1) = 6.4038 keV T. Ishiwatari CHIRAL05, Feb. 15-17, 2005 RIKEN (JAPAN)

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