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  1. n=1 p n=2 K- n=25 Proposal of an international facility at DANE2 From kaonic atoms to kaonic nuclei with DAFNE228-30 November 200531th LNF Scientific CommitteeC. Curceanu and J. ZmeskalDEAR/SIDDHARTA Collaboration

  2. (pre)Letter of IntentThe case of deeply bound kaonic nuclear statesProposal of an international facility at DANE2September 2005DEAR/SIDDHARTA CollaborationManifestation of interest from Institutions of:-Austria-Canada-France-Germany-Hungary-Italy-Japan-Poland-Romania-Russia-Sweden-USA-… Letter of Intent -> Spring 2006 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  3. AMADEUS AntikaonicMatterAtDAFNE: anExperimentUnravelingSpectroscopy 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  4. Contents1) Brief sketch of the scientific case of kaonic nuclear clusters2) From kaonic atoms to K-–nuclear bound states3) Current and future experiments => the unique features of DAFNE25) Features and identification of the setupand the experimental programme 6) First steps towards AMADEUS7) Formation of an international collaboration 8) Conclusions 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  5. A new paradigm in strangeness nuclear physics, with important consequences in fundamental physics, is represented by the recently observedDeeply bound Kaonic Nuclear stateswhose first experimental indications are being produced at - KEKand- LNF - GSI- BNL=> cold and dense nuclear system 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  6. KN interaction • Until 1997: Confusing situation (part due to KH puzzle) • 1997 KpX experiment at KEK Iwasaki et al. PRL(1997): K-p atom shift: DE1s“repulsive-type”, • Indicating the K-p interaction is strongly attractive 2002 DEAR results -> PRL 94, 212302 (2005) • Consistent with the view that L(1405): 1s bound state of K-p • Scattering data (no data at low energy) • 2002: Akaishi-Yamazaki constructed “Nuclear K bound states in light nuclei” Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002) 044005 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  7. Kaonic Nuclear Bound States • Believed (<2002) to be non-existing: G > EB • Akaishi-Yamazaki (2002) predicted: - K--p interaction so strong that it - might shrinks nuclei --> deeper bound states - deep enough that: the main decay channel KN-->Sp closed - strongly (deeply) bound states • EB > 100 MeV: narrow bound states (G<10 MeV) 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  8. First experimental indications: E471 ExperimentResults 4He(K-stopped, n) and 4He(K-stopped, p) missing mass spectra (M. Iwasaki et al., nucl-ex/0310018 v2) S0(3115): M = 3117 +3.8-2.0(sys)+/-0.9 (stat) G< 21.6 MeV, B= -194 MeVwith respect to K-+p+n+n rest mass Predicted NOT to exist! (B~20 MeV; G~100 MeV) S+(3140): M = 3117 +3.8-2.0(sys)+/-2.3 (stat) G< 21.6 MeV, B= -169 MeVwith respect to K-+p+p+n rest mass Predicted with B ~ 110 MeV M. Iwasaki et al., NIM A 473 (2001) 286 Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002) 044005 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  9. (AMD method Dote et al. 2002) 3He --->3HeK-shrinkage !! rc ~ 4 -10 r0 • Explore cold and dense nuclear states 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  10. Exploring dense nuclear states with K- bound states 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  11. Important impacts in fundamental physics -information concerning amodification of the kaon mass and of the KN interaction in the nuclear medium => interesting and important from the viewpoint of spontaneous and explicit symmetry breaking of QCD-information on a transition from the hadronic phase to a quark-gluon phase => changes of vacuum properties of QCD and quark condensate-kaon condensation in nuclear matter => implications on astrophysics: neutron stars, strange stars- nuclear dynamics under extreme conditions (nuclear compressibility, etc) couldbe investigated 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  12. From low-energy KN interactions to K-nuclear bound states “to what extent does our present knowledge of low-energy KN interactions support such expectations (the hypothesis of narrow K-nuclear statesintroduced by Akaishi and Yamazaki)?” (W. Weise, nucl-th/0507058) 1) the low-energy KN scattering data 2) the kaonic hydrogenshift of the ground state 3) thebinding energy and decay width of (1405), asserted to be an I=0 quasi-bound state of KN. Rate of formation and additional constraints: 4) Kaonic helium transitions The pillars of the existence of narrow K-nuclear states: 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  13. Future (expected) progress in the field:1) Kaonic Hydrogen and kaonic deuterium(SIDDHARTA: 200 + 500 pb-1) -> to ~ eV => I=0 and I=1 KN scattering lengths2) Low-energy scattering:A new facility at DANE2 to study K- nuclear clusters with a 4 detector, may include in its scientific program a K± scattering on nucleons/nuclei to build up a high quality set of data.3) (1405)Precise KN measurements at threshold (SIDDHARTA) will substantially improve the knowledge of the sub-threshold KN dynamics and contribute to clarify the nature of (1405). More information can come from the measurement of two-body branching ratios in K- absorption at rest, which is precisely the kind of reactions to be studied in the new facility at DANE2. Specifically, one can investigate in-medium corrections to the branching ratios in K- absorption at rest and their effect on the charged ± spectrum. . 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  14. 4) Kaonic Helium: SIDDHARTA (200 pb-1) - the rate + additional constraintsCrucial information about the formation of a specific deeply bound kaonic nuclear state (the K- 3He system) -> depends on the X ray transitions in the K- 4He atom.There are three experiments which observed kaonic helium atomic transitions from 3d to 2p levels, giving an experimental average value for the width G= 55 ± 34 eV. => the formation branching ratio turns out about 2%; right now -> E570 at KEK.The theoretical widths are around = 2-4 eV. Analogous discrepancy between experiments and optical models calculations does exists for the shifts. This is what is dubbed “the kaonic helium puzzle”.Preliminary Monte Carlo simulations, performed for the SIDDHARTA setup with a gaseous 4He target show that a measurement with a precision of eV can be performed at DANE with about 200 pb-1 of integrated luminosity. Similar estimations hold for the 3He case. The capability to detect kaonic helium X-rays transitions might turn out extremely useful in implementing an X-ray trigger to reduce the background in the measurement of kaonic nuclear states by capture at rest on 4He in a new dedicated facility at DANE2. . 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  15. KN low-energy scattering Kaonic Hydrogen and deuterium Deeply Bound Kaonic Nuclear States L(1405) 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  16. 1) Stopped K- reactions on light nuclei, with ejection of a proton or a neutron as spectators 2) In-flight K- reactions: - Knock-out reactions (K-, N) where one nucleon is knocked out in the formation stage; - (K-, π-) reactions in proton-rich systems to produce exotic bound nuclear states on unbound systems. 3)Protons (3.5 – 4.5 GeV) on a deuteron target for the production of K–ppdetected in a 4 detector. 4) The identification of clusters as residual fragments (“K fragments”) in heavy ion collisions via the invariant mass of their decay products. Identification and study of DBKNS: - Formation -> missing mass Decay -> invariant mass -> Spectroscopy! Production mechanisms of DBKNS: 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  17. FINUDA at DAFNE KEK: E549 E570 J-PARC (LOI06; LOI10) GSI (FOPI) Current and future planned experiments 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  18. Why DANE2 is a good place to study kaonic nuclear clusters (1)The future experiments in Japan (J-PARC) will produce kaonic nuclear states only withK--induced reactions in-flight (=1  2 GeV/c), either in (K-, N) or in (K-, -) processes. The alternative approach, followed at GSI, is represented by proton-nucleus collisions at beam energies close to the strangeness production threshold andnucleus-nucleus collisionsIt follows, that a dedicated facility at DANE2 can become THE scientific pole for studying kaonic nuclear states with K—induced reaction at rest. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  19. Why DANE2 is a good place to study kaonic nuclear clusters (2)The salient features of DANE2 are:-  Low-momentum (127 MeV/c) medium intensity chargedkaons:  1200/s at L 1033 cm-2s-1;-  Low momentum spread (<0.1%); -  Kpairs produced in aback-to-back topology;-  hadronic background intrinsically low – differently from anextracted beam. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  20. How DANE2 characteristics can be exploited at best for thestudy of strongly bound kaonic nuclear states?1) possibility to use either gaseous targets (as proven by DEAR) or thin targets (as proven by FINUDA). 2) Reducedneutron background generated by negative pion absorption(E47) exactly in the area of interest. The yield of these background neutrons depends on the equivalent g/cm2 of the target, namely on density and thickness, and on the materials put around the target itself. 3) The back-to-back topology which characterizes K- production, can be used to trigger on (K-, K+)-pairs, so selecting K-induced events. 4) Another trigger system might be implemented by taking advantage of the X rays emitted in the decay of the kaonic atom, created in the initial stage of the process. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  21. Features of the experimental setup • The complete study of the characteristic features of the kaonic bound nuclear systems requires knowledge of: binding energy, level width and partial widths, angular momenta, isospin, sizes, densities, etc. • This can be done by simultaneously observing the production stage of the K--clustersvia missing mass spectroscopy, and their decay products since their momentum correlations contain information on the internal structure of the exotic system. • It is therefore necessary to use a 4π dedicated detector capable of detecting all particles created in both the formation and decay of the K-clusters. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  22. Features of the experimental setup • Formation process: • Exotic nuclear states in light nuclei produced with (K-, N) reactions at rest will be observed by the energy distribution of the ejected protons and neutrons via the missing mass spectra of the (K-, p) and (K-, n) reactions. • The setup should be capable to measure: • Outgoing protons up to 600 MeV/c • Outgoing neutrons up to 600 MeV/c • in a 4π acceptance detector, with good efficiency and resolution. K- + 4He -> p + (K-pnn); p ~ 550 MeV/c K- + 4He -> n + (K-ppn); n ~ 510 MeV/c 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  23. K- + 4He -> n + (K-ppn) S-pp S0pn Lpn Ld np- Lg pp- pp- pp- (~64%) np0 np0 np0 (~36%) n(~500 MeV/c) 2p;n;g;p- 1p;2n;p0;g n(~500 MeV/c) 2pnp- n(~500 MeV/c) 2p;n;p- 1p;2n;p0 n(~500 MeV/c) p;d;p- n;d;p0 Features of the exp. setup: the decay process 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  24. Monte Carlo simulation: P(p) GeV/c P(n) GeV/c P(L) GeV/c n(~500 MeV/c) +Lnp ppnp- L -> p p-; n < 600 MeV/c; p- < 300 MeV/c P(p-) GeV/c 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  25. Features of the experimental setup Decay process The exotic states are expected to predominantly decay into final states containing  and S hyperons and protons, neutrons, deuterons or larger systems of nucleons. The most important feature of a detector is therefore the reconstruction capability for  and Shyperons from the invariant mass of their decay into nucleon +  and/or g. This implies good particle identification for these particles and their decay products. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  26. Features of the experimental setup Decay process From this data, frame-invariant Dalitzplots can be constructed, which are expected to reflect the size and density of the initial exotic state. Special attention must be paid to two-body correlations in a Dalitz plane, which may lead to a fake effect in an invariant mass spectrum  + p, which might be confused with the genuine mass of an exotic strange dibarion K-pp + p if all the three particles are not detected. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  27. Density distribution of K nuclear clusters  by observing the momentum correlation in their 3-body decay products (P. Kienle, Y. Akaishi, T. Yamazaki to be published in Phys. Lett. B) K-ppn   + p + n 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005 JZ / Nov. 29, 2005

  28. The detector satisfying all these features => • The KLOE detector • Performance of the KLOE 4p detector: • fully checked and exploited in the numerous measurements done already by KLOE; • studies of processes with BR of < 10-3 (10-6) • acceptance 96% • DC: sp/p ~ 0.4% • Spatial resolution of vertices in DC: 3 mm • dE/dx capacity for particle ID implemented • ECAL dE/Eg ~ 5.7%/E1/2 • st= (54/E1/2 + 50) ps • Ks->p+p- at 0.8 MeV/c2 • p0 mass resolution to 2-3 % (reconstruction) • Resol. for n of 500 MeV/c ~ 3% • …… 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  29. AMADEUS Experimental programme Measurements to be performed: The most fundamental system which we plan to study are thekaonic dibaryon states of ppK- and npK-, which are favorable produced using a3He gas target in 3He(K-, n/p) reactions. Their masses including their total width will be determined by neutron and proton energy measurements respectively. Exclusive measurements of their decays allow to extract further information: size/density, angular momentum, ... A similar programme is planned for kaonic 3-baryon states, populated in reactions using a 4He gas target. Furthermore we plan to extend these studies systematically over a broad rangeof nuclear targets starting by Li, B and Be. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  30. AMADEUS Experimental programme By observing momentum correlation in the three-body decay channel, such as pppK-  +p+p or ppnK-  +p+n, one will get information, using the correlation pattern in the Dalitz plane, of the size, density and the angular momentum of the involved kaonic cluster.  all decay products have to be identified  their 4-momenta have to be determined 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  31. The scientific programme of the nuclear cluster facility will be discussed in dedicated meetings and in the dedicated Workshop: “Exotic hadronic atoms, deeply bound nuclear states and antihydrogen: present results and future” to be held at ECT* (Trento), on June 19-24, 2006 Organizers: Catalina Curceanu (Petrascu) – LNF – INFN, Frascati (Italy) coordinator Eberhard Widmann , Stefan Meyer Institut für subatomare Physik - Austrian Academy of Sciences, Vienna (Austria) Akaki Rusetsky, Univ. Bonn, Germany 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  32. First actions towards AMADEUS 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  33. First actions towards AMADEUS • KLOE calorimeter efficiency for neutrons • Monte Carlo simple GEANT simulation => to be continued • => e500MeV/c > 20% (~30%) • b) KLOE+SIDDHARTA tests on KLOE calorimeter prototype • (long and short modules) on neutron beam: • n_TOF at CERN • BTF at LNF (?) 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  34. First actions towards AMADEUS • at n_TOF at CERN – if available in 2006 • Neutrons from 1 eV to 150 MeV energy • possibility to collimate the beam • 10 –100 MeV ~106n/pulse • dE/E (100 MeV) ~ 2% • Prepare request to Research • Board 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  35. First actions towards AMADEUS • at BTF (LNF) • Neutrons from photoproduction (-> 800 MeV electrons) • - Feasibility study (working group) 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  36. First actions towards AMADEUS • AMADEUS integration in KLOE: first drawing • to be continued with: • setup integration: gaseous and solid targets • Physics  Scientific program 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  37. Search for anti-kaon clusters with KLOE KLOE – EMC KLOE – Drift Chamber Possible setup for AMADEUS within KLOE: Cryogenic target Inner tracker Kaon trigger 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  38. Preliminary design: AMADEUS setup at KLOE • a first draft of the interaction region Kaon trigger Cryogenic target cell K+ K- DEAR beam pipe Inner tracker 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  39. Preliminary extrapolationsAMADEUS on KLOE setup confronted with KEK E471 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  40. E471 ExperimentResults 4He(K-stopped, n) and 4He(K-stopped, p) missing mass spectra M. Iwasaki et al., nucl-ex/0310018 v2 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  41. E471 features Theresults were obtained for a total number of about2 x 108 stopped negative kaons inside the liquid helium target. -        acceptance for detection of charged particles: 34%; -        detection efficiency for neutron: 36%; -        solid angle for the neutron/proton detector: 8%. With these conditions, the number of events in the missing mass spectra of the two reactions, are: - about 450 events in the (K-, p) reaction for the S0 (3115) neutral tribaryon, with a signal/background ratio about 1/10; -  about 120 events in the (K-, n) reaction for the S+ (3140) charged tribaryon, with a signal/background ration about 1/10; The formation ratios for the considered reactions turned out to be of the order of ~ 10-3. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  42. Extrapolation from KEK to DANE2 • more than 70% of kaons generated by –decay can be stopped, • with an optimized degrader, inside a gaseous helium target. • For a yearly integrated luminosity of about 10 fb-1, the total numbers of kaons generated in about 2 months (same time interval as at KEK) will be ~ 2 x 109 and ~ 1.4 x 109 will stop inside the target. • For a dedicated 4 detector we assume the following figures of merit: • acceptance for the detection of charged particles: 90%; • detection efficiency for neutrons detector: 30%; • solid angle for the neutron/proton detector: 90%. • Expected events in the case of a 4He target: • about 45000 in the (K-, p) reaction for the neutral tribaryon K-pnn • - about 12000 in the (K-, n) reaction for the charged tribaryon K-ppn 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  43. First actions towards AMADEUS Pre-experiment: PROPOSAL to KLOE The DC of KLOE  seen as an active target (4He) where => some K- stop => DBKNS DC K-pnn K- p 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  44. First actions towards AMADEUS • Pre-experiment: PROPOSAL to KLOE • A preliminary Monte Carlo simulation shows that with 2 fb-1 one might have due to K- stopped in the He gas of the DC: • > 1500 events of • -> the BEST measurement in the world • > 500 events of • AMADEUS group -> willing to help KLOE in • data analysis K- + 4He -> p + (K-pnn); p ~ 550 MeV/c K- + 4He -> n + (K-ppn); n ~ 510 MeV/c 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  45. Even more: 4He + K-  K-ppn + n K-ppn ° + d p + - K-ppn ° + p + n p + - n d - n p - - p p energy [MeV] 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  46. Formation of an international collaboration The Proposal is presented by physicists of the international collaboration DEAR/SIDDHARTA, which are working on DANE since 1996 and where they will be still engaged for the next three years. To the DEAR/SIDDHARTA collaboration belong 11 institutions from 8 different countries. The interest raised in the international community by kaonic atoms physics at DANE involved, since the beginning, also scientists from outside Europe, like Japan, USA and Canada, which actively participated and are participating to the experiments at DANE. =>“hard core” of an international collaboration does already exist. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  47. Formation of an international collaboration Other considerations support the strong appealing of the new initiative and consequently a potentially large interested community: The DANE2 with AMADEUS would represent the only facility in the worldwhere K—induced reactions at rest are studied. Moreover, after the GSI merging into FAIR, Frascati would be the only laboratory in Europe to go along this line of research. The fact to become the European counterpart with respect to the Japanese programmes at J-PARC reinforces the plan to apply to the Seventh Framework Programme of EU to obtain a substantial economical support both for developments of detectors and for the upgrading of the actual machine. Dec. 21-22, 2005Workshop on “Antikaon Mediated Bound Systems – Doorway to Kaon Condensation in Neutron Stars” 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  48. The scientific case of the study of deeply bound kaonic nuclear states deals with one of the most important, yet unsolved, problems in hadron physics: how the hadron masses and hadron interaction change in the nuclear medium and what is the structure of cold dense hadronic matter. Conclusions (1) After the shutdown of KEK in December 2005, two facilities will be active in the field: J-PARC in Japan, and GSI (FOPI) in Europe. The first one will produce kaonic nuclear clusters with K--induced reactions in flight. GSI will follow, before being absorbed in the new complex of facilities FAIR, an alternative approach, represented by nucleus-nucleus and proton-nucleon collisions. DANE2 can become theworld-scientific pole to study the K- induced processes at rest, which were indicated as the more direct way to investigate the clusters in nuclear matter. 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  49. Conclusions (2) • As far as the experimental setup is concerned, the 4p KLOE detector, implemented for AMADEUS program, operated in DAFNE2, satisfies the requirements to study the characteristic features of the K-nuclear clusters, which must consists both in observing the production stage of a K-nuclear clusters and detecting the decay products. • First steps towards the realization: • Monte Carlo intensive simulations • Measurement (KLOE+SIDDHARTA) of KLOE calorimeter • for n-efficiency • Feasibility of AMADEUS in KLOE • Possibility to participate to KLOE2 – new parts • Spring 2006 -> Letter of Intent 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

  50. From kaonic atoms to kaonic-nuclei Continuity and innovation Kaonic Hydrogen and deuterium KN low-energy scattering Deeply Bound Kaonic Nuclear States L(1405) An unique opportunity ONLY AT DAFNE2 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005