T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 1/3 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 behalf of the DEAR and SIDDHARTA Collaborations LNF SMI INFN Trieste Univ. Fribourg Univ. Neuchâtel RIKEN Univ. Tokyo Univ. Victoria

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 2/3 １ 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)% Shift:  1s = ± 37 (sta) ± 6 (sys) eV (replusive) Width:  1s = 249 ± 111 (sta) ± 30 (sys) eV Kaonic nitrogen X-ray yields at  =3.4  NTP Kaonic hydrogen K  line The results of the DEAR experiment PLB593(2004)48 Acta Physica Slovaca 55(2005)69, Submitted to PRL

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 3/3 １ The shift ε 1s and width Γ 1s in the 1s state both of kaonic hydrogen and deuterium Determination of isospin independent KN scattering lengths requires data both kaonic hydrogen and deuterium a 0 and a 1 are important for  deeply-bound kaon states, S 0 (3115), KN  -term, SU(3) chiral symmetry… Motivation S. Bianco et al., Rev. Nuovo. Cimento 22 (1999) 1.

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 4/3 １ E 1s  1s  1s } E 2p width  1s  [eV] shift  1s [eV] Davies et al, 1979 Izycki et al, 1980 Bird et al, 1983 repulsiveattractive KpX (KEK) M. Iwasaki et al, 1997  = ± 63 ± 11 eV  = 407 ± 208 ± 100 eV DEAR Kaonic hydrogen puzzle spd f Stark effect

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 5/3 １ K - p and K - d atoms Target K  line (eV) Shift  (eV)Width  (eV) X-ray yield Hydrogen6480~200~250~1-3% Deuterium7810~325 (?)*~630 (?)*~0.2% (?) Target7-6 transition Shift  (eV)Width  (eV) X-ray yield Nitrogen7596~0 ~50% 1.Kaonic hydrogen K  2.Kaonic deuterium K  high background 0. Kaonic nitrogen X-ray lines at high n transition *A.N. Ivanov et al., EPJA23(2005)79

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 6/3 １ Impact on kaonic nitrogen X-ray measurement The charged kaon mass The most precise values have a 60 keV difference m K = ±0.007 MeV (K - C: Denisov 91) m K = ±0.011 MeV (K - Pb: Gall 88) Electron screening effect must be studied N K Low density N e - High-density m K = ±0.016 MeV (PDG) PDG, PLB (2004)1 A new kaon mass measurement is proposed using a nitrogen gas. PLB 535 (2004) 52

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 7/3 １ DEAR DAΦNE (LN Frascati) electron – positron collider optimuzed to produce  meson at rest (1.020 GeV) electron – positron collider optimuzed to produce  meson at rest (1.020 GeV) TMP CCD Electronics Vacuum Chamber APD Cryo-Cooler Target Cell CryoTiger CCD Cooling CCD Pre-Amplifier CCD55-Chips kaons from Φ decay

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 8/3 １ DEAR experimental setup Shielding reduces background a factor~ 100

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 9/3 １ Experimental Setup TMP CCD Electronics Vacuum Chamber APD Cryo-Cooler CryoTiger CCD Cooling CCD Pre-Amplifier CCD55-Chips e + e - kaons from Φ decay

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 10/3 １ DA  NE Luminosity Φ production cross section ~ 3000nb (corrected for radiative losses) Integrated luminosity ~ 2pb -1 per day  ~ 3 × 10 6 K - per day Φ production cross section ~ 3000nb (corrected for radiative losses) Integrated luminosity ~ 2pb -1 per day  ~ 3 × 10 6 K - per day Kaon Monitor kaons are directly measured by the scintillators.

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 11/3 １ CCD Detector 16 CCD55-30 chips are used x 1152 pixels - pixel size 22.5 x 22.5 µm - total area per chip 7.24 cm 2 - depletion depth ~30 µm - read-out time 2 min. - energy resolution ~150 6keV - temperature stabilized at 165 K 16 CCD55-30 chips are used x 1152 pixels - pixel size 22.5 x 22.5 µm - total area per chip 7.24 cm 2 - depletion depth ~30 µm - read-out time 2 min. - energy resolution ~150 6keV - temperature stabilized at 165 K

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 12/3 １ 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 , 2005 RIKEN (JAPAN) 13/3 １ Selecting single- and double-pixel events as X-rays gives excellent background rejection X-ray events

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 14/3 １ Experimental Data Kaonic Nitrogen April: : ~9000 × 16 files (160GB) 14.2 pb -1 => 20.5 × 10 6 K - Kaonic Nitrogen October: : ~7000 × 16 files (112GB) 17.4 pb -1 => 25.1 × 10 6 K - Kaonic Hydrogen: : ~18000 × 16 files (288GB) 58.4 pb -1 => 84.1 × 10 6 K - Hydrogen, no collisions: : ~2600 × 16 files (42GB) No kaons. Removed scrapers to produce high background

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 15/3 １ Kaonic Nitrogen X-ray Spectrum Al Si Ca Zr 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. The number of each X-ray peaks are obtained by the fit. Efficiencies for kaons to stop the target, and for X-rays to be detected by the CCDs are estimated by the Monte Carlo pb -1

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 16/3 １  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) m K - = ± MeV Results of kaonic nitrogen Δm K - = 60 keV Future measurement will allow to solve this problem

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 17/3 １ Kaonic Hydrogen  1s  1s s p d f E 1s } E 2p n K   keV KK Negligible shift and width in the n>1 states Fe K  = 6.4 keV Y(KH) ~ 1-3% S/N~1:100 The yield of kaonic hydrogen is small, and the energy is close to Fe K .

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 18/3 １ Kaonic Hydrogen X-ray spectrum Raw spectrum (background fitted with cubic function)

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 19/3 １ Experimental Data Kaonic Nitrogen April: : ~ 9000 × 16 files (160GB) 14.2 pb -1 => 20.5 × 10 6 K - Kaonic Nitrogen October: : ~ 7000 × 16 files (112GB) 17.4 pb -1 => 25.1 × 10 6 K - Kaonic Hydrogen: : ~ × 16 files (288GB) 58.4 pb -1 => 84.1 × 10 6 K - Hydrogen, no collisions: : ~2600 × 16 files (42GB) Background measurement without crossing beams at the IP

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 20/3 １ Countinuous background shapes are subtracted. Two spectra are normailized. Intensity of Fe K  line from background data Energy difference of K-lines are fixed. Same Lorenzian width for the K-lines Relative yields for K ,K high... are examined Stability tests for the fits with several fit ranges Background subtracted spectra

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 21/3 １ Kaonic hydrogen X-ray spectrum X-ray energy spectrum with subtraction of all the background components Shift:  1s = ± 37 (stat.) ± 6 (syst.) eV Width:  1s = 249 ± 111 (stat.) ± 30 (syst.) eV Shift:  1s = ± 37 (stat.) ± 6 (syst.) eV Width:  1s = 249 ± 111 (stat.) ± 30 (syst.) eV Repulsive shift K , K  and K  are clearly disentangled, for the first time With small errors

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 22/3 １ Results of kaonic hydrogen width  1s  [eV] KpX shift  1s [eV] Davies et al, 1979 Izycki et al, 1980 Bird et al, 1983 repulsive attractive KpX (KEK) M. Iwasaki et al, 1997  = ± 63 ± 11 eV  = 407 ± 208 ± 100 eV DEAR  1s = ± 37 (stat.) ± 6 (syst.) eV  1s = 249 ± 111 (stat.) ± 30 (syst.) eV a K - p = ± i ± fm

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 23/3 １ 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 , 2005 RIKEN (JAPAN) 24/3 １ Kaon – X-ray coincidence Triple coincidence: SDD X * Scint K * Scint K Scintillator D 2 gas SDD e+e+ e-e-  X-ray K+K+ K-K- Φ  K + + K - An improvement of the S/ N of ~ 2 – 3 orders of magnitude S/N =1:100  5:1 for kaonic Hydrogen

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 25/3 １ SDD design for SIDDHARTA sensitive area 3 x 100 mm² chip size: 34 x 14 mm² integrated temperature sensors

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 26/3 １ Possible SDD and target setups New design for triggered target-detector system Large area SDDs (1cm 2 each, total area ~ 200 cm 2 ) e+e+ e-e- Cryogenic gas target volume SDDs Scintillators R L (1) toroidal topology With 200 cm 2 SDDs, only part of the cylindrical surface can be covered SDDs e-e- e+e+ (2) Conventional topology Trigger scintillators not shown

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 27/3 １ Kaonic deuterium (Monte Carlo) Energy (keV) SDD w/o coinc. coinc. SDD * Scint * Scint Background suppression to > 10 3 Kaonic deuterium KK K  Ag K fluorescence lines (calibration) Width  1s ~ 630 eV Shift  1s ~ 330 eV A.N. Ivanov et al., EPJA23(2005)79 Yield Y(K  ) ~ 0.2% MIPs (e + /e - ) in SDD Kaon decays  = 15 eV  =35 eV S/B=1:1 Signal rate ~ 2.2x10 -3 /s 130 /d (duty cycle=2/3 of d.)

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 28/3 １ Kaonic Helium-4 Puzzle (large shift and width in 2p state) E (Fe K  ) = keV E(exp)-E(Fe)= ~10 eV K-He L    p (eV)   p (eV) Experiments Baird (’83)-50 ± 12100±40 Batty (’79)-35 ± 1230±30 Wiegand(’71)-41 ± Theory Baird (’83) Akaishi (’02) Kaonic helium puzzle Akaishi (’02)-1121 Assuming a deeply bound kaon state exists (YA02 model) Abnormal shift and large uncertainty in width In the kaonic 4 He 2p state

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 29/3 １ Summary The results of kaonic hydrogen are Repulsive shift of the K  line is verified. Most accurate determination of the shift and width. Kβ, K  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 , 2005 RIKEN (JAPAN) 30/3 １ 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 charged kaon mass. SIDDHARTA Silicon Drift Detectors for Hadronic Atom Research by Timing Applications SIDDHARTA Silicon Drift Detectors for Hadronic Atom Research by Timing Applications

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 31/3 １ News on exotic atoms International Conference on Exotic Atoms, EXA05 February 21 – 25, 2005 Vienna

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 32/3 １ Kaonic Hydrogen Data Analysis Determination of background shape Finding all the fluorescence X-ray peaks 1.Kaonic hydrogen spectrum 2.“no collision” spectrum 3.Kaonic nitrogen spectrum subtraction of the continuous background and fluorescence X-ray lines as Background data as Signal data

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 33/3 １ SDD structure SDD with integrated JFET Detector produced at the MPI Halbleiterlabor, Munich, Germany

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 34/3 １ Exp. = liq. 4 He No experiment of 3 He E (K He L  ) = keV E (Fe K  ) = keV

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 35/3 １ K-He L    p (eV)   p (eV) Experiments Baird (’83)-50 ± ± 40 Batty (’79)-35 ± 1230±30 Wiegand (’71)-41 ± Theory Baird (’83) Akaishi (’02) Kaonic helium puzzle Akaishi (’02)-1121 Assuming a deeply bound kaon state exists (YA02 model) E 2p (K He) = keV E (Fe K  ) = keV

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 36/3 １ TransitionE (calc.)E (exp.)Rel. Int.Yield(%) 3d-2p ± ±68.9±4.5 4d-2p ±42.3±1.2 5d-2p ±31.6±0.8 6d-2p ±30.4±0.3 Energies & yields of K-He L lines (Baird) E (Fe K  ) = keV E(exp)-E(Fe)= ~10 eV

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 37/3 １ Kaonic He L X-ray yields (Koike)

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 38/3 １

T. Ishiwatari CHIRAL05, Feb , 2005 RIKEN (JAPAN) 39/3 １ Exp. = liq. 4 He No experiment of 3 He E (K He L  ) = keV E (Fe K  ) = keV