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Low-energy anti-kaon nucleon and nuclei interactions J. Marton Stefan Meyer Institute Austrian Academy of Sciences, Vienna 19th IUPAP Conference on Few.

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Presentation on theme: "Low-energy anti-kaon nucleon and nuclei interactions J. Marton Stefan Meyer Institute Austrian Academy of Sciences, Vienna 19th IUPAP Conference on Few."— Presentation transcript:

1 Low-energy anti-kaon nucleon and nuclei interactions J. Marton Stefan Meyer Institute Austrian Academy of Sciences, Vienna 19th IUPAP Conference on Few Body Problems1

2 Scope A kind of overview on open problems and current and future attempts to solve them (here I want to focus on dedicated experiments) Topics which are in the scope of the LEANNIS network of the EU project HadronPhysics2 Few Body problems involving strangeness: Specific talks on theoretical approaches and experiments (experiments: M. Iio, O. Vazques Doce, S. Okada, Y. Fujiwara) at this Conference 19th IUPAP Conference on Few Body Problems2

3 Content Motivation for new (experimental) studies Exotic (hadronic) atoms – threshold data – Kaonic hydrogen isotopes (strong interaction effect on 1s) – Kaonic helium isotopes (strong interaction on 2p) Search for bound strange nuclear systems (K - pp, K - ppn …) – K- stopped – K- in-flight – pp collisions New ideas Status and Outlook 19th IUPAP Conference on Few Body Problems3

4 Motivation for new studies The low-energy kaon-nucleon interaction is neither simple nor well understood Central importance for the physics of strong interaction has the dynamics driven by chiral symmetry breaking in low-energy QCD Problems arise from the existence of hyperon resonances like the Λ(1405) Problems arise also due to 2 nucleon K - absorption possibly imitating bound states The development of reliable theories suffers from the lack of precision data on the observables at threshold (e.g. shift/width of kaonic atoms) 19th IUPAP Conference on Few Body Problems4 Interesting question: Two-pole structure?? Λ(1405) & Λ(1420) and their impact

5 Sources of experimental information on the low energy (anti)kaon-nucleon interaction Kaon-proton scattering data (old data with large errors, above threshold  extrapolation) πΣ mass spectrum Threshold decay ratios X-ray data of light kaonic atoms (K - p, K - d, K - He): see talks by S. Okada and Iio at this conference – Kaonic hydrogen  increase precision, threshold data important input for theory – Kaonic deuterium  first experimental studies, threshold data important input for theory – Kaonic helium-4  2p shift small (KEK 570), rules out „superstrong“ antikaon nuclear interaction – Kaonic helium-3  first experimental studies Reliable theory has to cope these informations 19th IUPAP Conference on Few Body Problems5

6 Kaonic hydrogen and deuterium Strong interaction effects manifest in hadronic shift and width of the 1s state, i.e. deviation from the electromagnetic value of the 1s state and broadening due to absorption which can be calculated with an accuracy of about 1eV by solving the Klein-Gordon (KG) equation and taking into account vacuum polarization (VP) and final size (FS) effect. Strong interaction effect on 2p state is weak (meV) and experimentally undetermined, but has severe consequences for the x-ray yield 19th IUPAP Conference on Few Body Problems6

7 X-ray yields 19th IUPAP Conference on Few Body Problems7 Strong interaction on 2p level  2p width Γ 2p Γ 2p limits yield - but is poorly known M. G. Raisi and S.Z. Kalantari, PRA 79 (2009) p width R.C. Barrett, A.Deloff meV PRC 60(1999) T. Koike et al.25 meVPRC 53 (1996) 79 M.P. Faifmann4 ±2 meVProc. DAFNE99 K-d K-p

8 Threshold data on kaonic hydrogen 19th IUPAP Conference on Few Body Problems DEAR (2005)  1s = ± 37 (stat.) ± 6 (syst.) eV  1s = 249 ± 111 (stat.) ± 30 (syst.) eV a K-p = ( ± ± 0.015) + i(0.302 ±0.135± 0.036) fm KpX (1998)  1s = ± 63 (stat.) ± 11 (syst.) eV  1s = 407 ± 208 (stat.) ± 100 (syst.) eV a K-p = (-0.78 ± 0.15 ± 0.03) + i(0.49 ±0.25± 0.12) fm using Deser-Trueman (i.e. lowest order) DEAR (2005)  1s = ± 37 (stat.) ± 6 (syst.) eV  1s = 249 ± 111 (stat.) ± 30 (syst.) eV a K-p = ( ± ± 0.015) + i(0.302 ±0.135± 0.036) fm KpX (1998)  1s = ± 63 (stat.) ± 11 (syst.) eV  1s = 407 ± 208 (stat.) ± 100 (syst.) eV a K-p = (-0.78 ± 0.15 ± 0.03) + i(0.49 ±0.25± 0.12) fm using Deser-Trueman (i.e. lowest order)  solved the so-called "kaonic hydrogen puzzle"  interaction is repulsive  Precision limited (e.g. error bar of width > 50%)  Most precise values for shift and width from DEAR experiment (CCDs)  But still precision limited  shift vs. width (1 σ errors) see below 8

9 Close interconnection between experiment and theory 19th IUPAP Conference on Few Body Problems9 Example K-p: extraction of scattering lengths from experimenta data Even more challenging is the case of kaonic deuterium Lowest order: Deser-Trueman NLO: Isospin breaking corrections U.-G- Meißner, U. Raha and A. Rusetsky, Eur. Phys.J. C35 (2004) 349

10 KN interaction at threshold 19th IUPAP Conference on Few Body Problems B. Borasoy, R. Nißler and W. Weise, Phys. Rev. Lett. 94, (2005) K-p: repulsive at threshold, attractive below threshold threshold DEAR data real part Imag. part 10

11 New experiments -- new (x-ray) detectors Silicon Drift Detectors with large active area active area  100 mm 2 Excellent energy resolution, timing 2 different types for exotic atom research  SDD with external FET (commercial product, KETEK) system studied: K -4 He (E570/KEK), K -3 He (E17/J-PARC)  SDD with on chip integrated FET  SIDDHARTA (JRA10/EU-FP6) systems to be studied:K - p, K - d …. 19th IUPAP Conference on Few Body Problems11

12 Kaonic nuclear clusters ? Prototype system K - pp 19th IUPAP Conference on Few Body Problems12

13 Recent developments in theory Faddeev calculations See talk by N. Shevchenko at this Conference Binding energy: 55 – 70 MeV Decay width: 95 – 110 MeV N. Shevchenko, et al. PRL 98 (2007) N. Shevchenko et al. PRC (2007) Y. Ikeda, T. Sato PRC 76 (2007) Variational calculations Binding energy: MeV Decay width: MeV T. Yamazaki, Y. Akaishi PRC 76 (2007) A. Dote, T. Hyodo, W. Weise NPA 804 (2008) 197 A. Dote, T.Hyodo, W. Weise PRC 79 (2009) th IUPAP Conference on Few Body Problems 13

14 VC OBELIX, NPA789 (2007)222 FINUDA PRL94 (2005) DISTO, preliminary Proc. EXA/LEAP09, Hyp. Int. in print FC FINUDA PRL94 (2005) OBELIX, NPA789 (2007)222 DISTO, preliminary Proc. EXA/LEAP09, Hyp. Int. in print FC VC K - pp: Comparison experiment-theory VC … Variational calculations AY02 … VC Akaishi and Yamazaki PL B535 (2002) 70 FC … Faddeev calculations AY02 Not a clear picture

15 Production of antikaon-mediated bound nuclear cluster (KNC)? stopped K - reactions on light nuclei in-flight K - reactions protons on proton (or light nuclei) heavy ion collisions antiproton induced reactions dedicated experiments exclusive measurement 19th IUPAP Conference on Few Body Problems 15

16 Search for kaonic nuclear clusters with AMADEUS at LNF 19th IUPAP Conference on Few Body Problems AMADEUS collaboration: 114 scientists from 13 Countries and 33 Institutes lnf.infn.it/esperimenti/siddharta and LNF-07/24(IR) Report on lnf.infn.it web-page (Library) 16 Search for kaonic nuclear systems with S-1 using K- stopped in helium gas and employing the modified KLOE apparatus at DA ΦNE/LNF for exclusive experiments Search for kaonic nuclear systems with S-1 using K- stopped in helium gas and employing the modified KLOE apparatus at DA ΦNE/LNF for exclusive experiments See talk by O. Doce Vazquez

17 K - pp production in pp reaction with FOPI 19th IUPAP Conference on Few Body Problems Experimental search for the most simple KNC – the prototype system ppK - with missing mass spectroscopy invariant mass reconstruction  Presently taking data at GSI 17 p on hydrogen target at 3 GeV

18 Search for K - pp in flight 3 He(K -,n) reaction, experiment in connection with E17 K-K- 3 He (liquid) reaction Search for K - pp bound state with  Missing mass spectroscopy and  Invariant mass reconstruction K - pp cluster neutron  p p -- Charged particles decay Missing mass spectroscopy by n detection decay Invariant mass reconstruction 19th IUPAP Conference on Few Body Problems18

19 New ideas Search for kaonic nuclear clusters S-2 (double strangeness) Production via antiproton annihilation proposed, E B > 100 MeV 19th IUPAP Conference on Few Body Problems19 Proposed by P.Kienle (*), T.Yamazaki and W.Weise (**) (*) Int. Jour. Mod. Phys. A 22 (2007)365 (**) arXiv:nucl-th/ v1 (2005) Idea supported by Obelix data

20 New experiments? Requirements for pbar annihilation studies at rest: (J. Zmeskal et al. Proc. EXA08, Hyp. Int. In print) – Low-energy pbar beam: AD/CERN, FLAIR/FAIR – Detector for exclusive annihilation studies in nuclei Start counter – scintillating fibers with Geiger Mode - APD readout PID – with a TPC - GEM (similar as proposed for PANDA) For neutral particle detection - a Calorimeter with alternating scintillating fibres – lead layers (KLOE-type) – High statistics 19th IUPAP Conference on Few Body Problems20

21 Status and Outlook New experiments on threshold data (shift, width) of light kaonic atoms are running or in preparation Threshold data are crucial prerequisites for the theoretical description (enhancement of the predictive power for sub-threshold) Challenge: Nature of Λ(1405) – 2-pole structure? Can one investigate this question experimentally? Theoretical studies on the question of kaonic nuclear clusters are ongoing (Faddeev, variational calculations) Evidence for existence of kaonic nuclear clusters (FINUDA, OBELIX, DISTO, …) New fully exclusive experiments with various reactions are indispensible and are in preparation New idea: Kaonic nuclear cluster with double strangeness produced in antiproton annihilation 19th IUPAP Conference on Few Body Problems21

22 Thank you 19th IUPAP Conference on Few Body Problems22 If you haven't found something strange during the day, it hasn't been much of a day. (A. Wheeler) No phenomenon is a real phenomenon until it is an observed phenomenon. John Archibald Wheeler John Archibald Wheeler

23 Spare 19th IUPAP Conference on Few Body Problems23

24 Interconnection experiment-theory cont‘d Extrapolation of subthreshold behavior from experimental data 19th IUPAP Conference on Few Body Problems24 πΣ mass spectrum extrapolation from analysis of data above threshold (B. Borasoy, R. Nissler and W. Weise, Eur.J. A25 (2005) 79) Precision threshold data (SIDDHARTA) will increase the predictive power K - p threshold

25 Experiments KN threshold studies by x-ray spectroscopy – see talks by S. Okada and Iio at this conference Search for quasi-bound nuclear systems with S=-1 DISTO, – see talk by O. Doce Vazquez on AMADEUS at this Conference Search for quasi-bound nuclear systems with S-2 (OBELIX, CERN AD, FLAIR) 19th IUPAP Conference on Few Body Problems25

26 Comparison of chiral and phenomenological KN interaction 19th IUPAP Conference on Few Body Problems T. Hyodo and W. Weise, PR C77 (2008)


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