Probing strong interaction with kaonic atoms - from DA  NE to J-PARC Johann Zmeskal Stefan Meyer Institute for Subatomic Physics Vienna, Austria The 12 th International Conference on Hypernuclear and Strange Particle Physics September 7-12, 2015 Tohoku University, Sendai, Japan Stefan Meyer Institute

Outline HYP2015 Motivation Measuring principle SIDDHARTA setup at DA  NE Results of kaonic helium and hydrogen Kaonic deuterium at J-PARC Summary

Low-energy KN interacction  Chiral perturbation theory was developed for  p,  is not applicable for KN systems non-perturbative coupled channels approach based on chiral SU(3) dynamics HYP2015

Exotic (kaonic) atoms – probing strong interaction  testing chiral symmetry breaking in systems with strangeness Why kaonic hydrogen?  observable: hadronic shift ε 1s and width Γ 1s  can be connected to KN scattering lengths  scattering lengths, no extrapolation to zero energy Motivation: Low-energy KN systems

1) U.-G. Meißner, U.Raha, A.Rusetsky, Eur. phys. J. C35 (2004) 349 next-to-leading order, including isospin breaking Scattering lengths Deser-type relation 1) connect the observables shift  1s and width  1s of the 1s state with the real and imaginary part of the scattering length ɑ K-p (µ C reduced mass of the K  p system,  fine-structure constant)

n=1 p e-e- K-K- “normal” hydrogen“exotic” (kaonic) hydrogen n=1 n=2 n~25 K-K- X-ray 2p → 1s K  transition Forming “exotic” atoms HYP2015

Stark-mixing l =0 1 2 n-1 n ~ observable hadronic shift and broadening  1s  1s external Auger effect chem. de-excitation Coulomb de-excitation X-ray radiation K K nuclear absorption Cascade processes

X-ray transitions to the 1s state HYP2015

Kaonic hydrogen atoms at DA  NE e + -e - collider LINAC Accu. HYP2015

 K+K+ K-K- ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee DA  NE principle operates at the centre-of-mass energy of the  meson mass m = ±.008 MeV width  = 4.43 ±.06 MeV  produced via e + e - collision with  (e + e - →  ) ~ 5 µb   production rate 2.5 x 10 3 s -1 → monochromatic kaon beam (127 MeV/c) HYP2015

DA  NE DetectorSi(Li)CCDSDD Energy resolution350 eV180 eV150 eV Time resolutionµs30 sµs Thicknessmm30 µm400 µm Efficiency at 6 keV~ 100%~ 60%~ 100% Active area120 cm cm cm 2 Detectors for K - p experiments HYP2015

SDD window frame (pure Al %) flexible Kapton boards pre-amplifier board HV+LV distribution board Development of large area SDDs FP-6 EU programme: HadronPhysics HYP2015 3x100 mm 2

FWHM = 150 6keV Excellent energy resolution HYP2015

Alu-grid Side wall: Kapton 50 µm Kaon entrance Window: Kapton 75 µm working T 25 K working P 1.5 bar Lightweight cryogenic target cell HYP2015

Advanced Seminar Series Particles and Interactions SIDDHARTA target - detector HYP2015

SDDs degrader Scintillators Production data K + K - pairs produced at DA  NE Data taking scheme at DA  NE HYP2015 triple coincidence

“X-ray tube” data taken with “beam” ON Data taking scheme at DA  NE HYP2015

“X-ray tube” data taken estimated systematic error ~ 3-4 eV SDD X-ray energy spectra energy [keV] counts / 30eV HYP2015

SDD X-ray energy spectra HYP2015

K - 3 He (3d-2p) Ti K  K-CK-C K-OK-O K-NK-N QED value: E em = eV PLB 697(2011)199 First observation of K- 3 He X-rays Kaonic helium-3 measurement HYP2015

Kaonic helium results HYP2015  E17 at J-PARC (Shinji Okada)

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 results Kaonic hydrogen: KpX and DEAR results HYP2015

Kaonic SIDDHARTA HYP2015 Calibration data with X-ray tube All events (“self trigger”) Coincidence: K + K  and SDD timing

K - p spectrum after BG subtraction HYP2015

State of the art: Kaonic hydrogen ε 1s = -283 ± 36(stat) ± 6(syst) eV Γ 1s = 541 ± 89(stat) ± 22(syst) eV HYP2015 SIDDHARTA

HYP2015 Improved constraints on chiral SU(3) dynamics from kaonic hydrogen, Y. Ikeda, T. Hyodo and W. Weise, PLB 706 (2011) 63

W. Weise HYP2015

20 Institutes / 10 Countries K-d at J-PARC

HYP2015 K  d at J-PARC X-ray detection: large active area charge particle tracking lightweight cryogenic target stopped K 

8 x 8 mm 2 single SDD Array: 9 SDDs (8 x 8 mm 2 each) 12 x 12 mm single SDD FBK production: 4’’ wafer 6’’ wafer upgrade just finished New Silicon Drift Detector developed by Politech Milano and FBK-Trento, Italy 26mm

16 mm + 2 mm 8 mm border 1 mm SDD active area 8 mm x mm + 2 mm = 38mm additional border 2 mm Design of the new SDD array ceramic boards cell size: 8 x 8 mm 2 cells per array: 8 active area: 5.12 cm 2 total area: 6.84 cm 2 HYP2015

Prototype of the new 4x2 SDD array SDD-chip back side with bonding pads connector 9 holes for bondings CUBE preamplifier SDD-chip glued to ceramic board, bonded to CUBE preamplifier

New SDD technology with CUBE preamplifier HYP Fe spectrum eV FWHM SDD characteristics: area = 64 mm 2 T = - 100°C first series of new SDD-chips available

HYP2015 Synchronous and asynchronous background Synchronous BG

charged particle veto charged particle tracking HYP2015

K1.8BR experimental area J-PARC K1.8BR spectrometer neutron counter beam dump beam sweeping magnet liquid 3 He-target system CDS beam line spectrometer K-K- γ, n p 15m

HYP2015 T1 T0 main degrader CDC BLC CDH Solenoid SDD and deuterium target CDH...cylindrical detector hodoscope CDC...cylindrical drift chamber T beam line counter T beam line counter BLC....beam line chamber K  d within the K1.8BR spectrometer

HYP2015 KK start counter T0 entrance window 75 µm Kapton Al reinforced side wall 75 µm Kapton 12 x 4 SDD arrays SDD cooling and support target cell: l = 160 mm, d = 65 mm target pressure max.: 0.35 MPa target temperature: 23 – 30 K SDD active area: 246 cm 2 density: 5% LHD (29K/0.35 MPa) Combined target and SDD design

HYP2015 K  d scattering lengths - theory a Kd [fm]  1s [eV]  1s [eV]Reference i Weise 2015 [2] i Mizutani 2013 [4] i Shevchenko 2012 [5] i Meißner 2011 [1] i Gal 2007 [6] i Meißner 2006 [7] i Oset 2001 [3] [1] M. Döring, U.-G. Meißner, Phys. Lett. B 704 (2011) 663 [2] W. Weise, arXiv: [nucl-theo]2015 [3] S.S. Kamakov, E. Oset, A. Ramos, Nucl. Phys. A 690 (2001) 494 [4] T. Mizutani, C. Fayard, B. Saghai, K. Tsushima, Phys. Rev. C 87, (2013), arXiv: [hep-ph] [5] N.V. Shevchenko, Nucl. Phys. A (2012) [6] A. Gal, Int. J. Mod. Phys. A22 (2007) 226 [7] U.-G. Meißner, U. Raha, A. Rusetsky, Eur. phys. J. C47 (2006) 473 for simulation: shift = eV width = 800 eV

HYP2015 Geant4 simulated K  d X-ray spectrum for 160 kW·weeks achievable precision: shift: 60 eV width:140 eV signal: shift eV width 750 eV density: 5% (LHD) detector area: 246 cm 2 K  yield: 0.1 % yield ratio as in K  p S/B ~ 1 : 3 QED  vertex cut  charged particle veto  asynchronous BG KK KK K high

DA  NE X-ray spectra measured with several targets:  K  p: provided the most precise values (PLB 704 (2011) 113)  K  d: first exploratory measurement (Nuclear Physics A 907 (2013) 69)  K  3 He: first-time measurement (PLB 697 (2011) 199)  K  4 He: measured in gaseous target (PLB 681 (2009) 310) K  d at J-PARC (P57)  stage 1 approval – new SDDs with cryogenic gas target – K1.8 BR spectrometer Summary HYP2015