PoS()037 http://pos.sissa.it/ -mesons decaying nearly at rest. The Φ d the isospin-dependent antikaon- scattering − p and K − NE Research) experiment at LNF delivered the most precise data † ∗ Φ NE - collider of Laboratori Nazionali di Frascati we study kaonic Φ system at rest makes a sensitive testing ground for chiral SU(3) symmetry in QCD, KN [email protected] Speaker. Work partly supported by EU within I3-HadronPhysics and TARI-INFN, Contract No. RII3-CT-2004-506078. The especially for the explicit symmetryquark. breaking induced by the relativelyAt large mass the of DA the strange atoms, taking advantage of thelow-energy antikaon-nucleon low-energy interaction in from kaonic hydrogentigated and under kaonic favorable conditions. deuterium can beThe inves- DEAR (DA on kaonic hydrogen up to now.Detector DEAR for and Hadronic its Atom follow-up experiment Researchkaonic SIDDHARTA (Silicon by atoms Drift to Timing measure Application) the are strongDHARTA using will interaction X-ray induced be spectroscopy shift the and of first widthremeasured of with experiment the greatly on ground improved precision. kaonic state. deuterium SID- From ever, the and shift kaonic and hydrogen width will be in K lengths can be determined, quantities essential as constraints for low-energy QCD. ∗ † Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. c ° on behalf of the SIDDHARTA collaboration Michael Cargnelli Kaonic X-ray experiments at DAFNE using SIDDHARTA Stefan Meyer Institut for Subatomic Physics,E-mail: Austrian Academy of Sciences. KAON International Conference May 21-25 2007 Laboratori Nazionali di Frascati dell’INFN, Rome, Italy PoS(KAON)037 ] 9 (1405), only Λ Michael Cargnelli ]. The existence 8 (1405) dynamically Λ ]. Their fit restricted to 4 ] on scattering lengths derived from 7 ]. ] are given by the gray boxes. The open 12 2 channel. A general feature of the theory ][ 1 Σ π 2 mass spectrum and the kaonic atom data from DEAR; interaction at threshold is important for the search scattering are rare, poor in statistics and conflicting, Σ π KN KN scattering lengths, in addition to kaonic hydrogen a mea- KN and KN p: experimental results [ − ] if the authors apply the Deser formula [ 3 ] 5 ][ 9 Shift and width of K ][ quasibound state and as a resonance in the 6 ][ KN The kaonic atom experiments deliver input for theory and are also tools to test the ability of To extract the isospin dependant Furthermore the understanding of the There are however non-perturbative coupled-channel techniques based on the driving terms of Low energy phenomena in can not (yet?) be described in terms of quarks 4 ][ 3 triangle denotes the value in [ a fit using scattering data,the branching filled ratios, triangle the gives thethe value DEAR when data they results include in isospin the breaking open and corrections filled [ square respectively. The dot gives the result from [ Figure 1: surement of kaonic deuterium is necessary, which is the central goal of our experiment. theoretical models to accommodate thestimulated set by of recent experimental and values. ongoing experimental The work.[ vividness For of some the of field the newer was theoretical works see: as a in this field is thatscattering experiments, it atomic relies x ray heavily measurements on andThe the input existing energy from data and width experimental on of low data. known energy furthermore resonances. the The extrapolation data to comes zero from energy introduces kaon model dependencies. of these kaonic clusters is stillthroughout controversial, the various world, new at experiments LNF are the currently AMADEUS being experiment planned [ the chiral effective Lagrangian which proved to be useful. They generate the and gluons. Instead, effective field theories areto used describe that physical contain the phenomena appropriate occurring degrees at ofthe a freedom degrees chosen of length freedom scale, at but shorter ignoretheory distances the was (corresponding substructure and to extremely higher successful energies). inapplicable Chiral perturbation describing for systems the kaonic like systems. pionic atoms, This unfortunately is it due is to not presence of resonances like the Kaonic X-rays 1. Kaonic atoms in low energy QCD slightly below the reaction threshold. for kaon nuclear clusters as predicted by the model of Akaishi and Yamazaki [ PoS(KAON)037 Michael Cargnelli and a thickness of 450 2 3 NE originates almost entirely from electromagnetic Φ 25). Via different cascade processes (Auger transitions, ' ]. See fig.1 for a compilation of experimental and theoretical 2 ]. In an advanced SDD design optimized for X-ray spectroscopy there is of SDDs and 2 x 3 trigger scintillators to tag on the charged kaons. 11 2 Schematic view of the energy levels of kaonic hydrogen showing the shift and width due to strong Silicon Drift Detectors (SDDs) are based on the principle of sideward depletion introduced Since the soft X-ray background at DA The SDD chips developed by the company PNsensor and the MPI for extraterrestrial physics In a previous experiment at LNF (DEAR) we obtained the most precise results for kaonic A kaonic atom is formed when a negative kaon enters a medium, looses its kinetic energy m. Three of these structures are integrated on one chip, 2 chips make up a SDD detector module. µ by Gatti and Rehak [ no field-free region, the whole volume is sensitive to the absorption of ionizing radiation. Each within the project have a nearly square structure with an active area of 1 cm hydrogen existing up toresults, now. fig.2 to [ illustrate the shiftin and DEAR width was of clearly transitions limited in byespecially kaonic the for atoms. poor signal kaonic The to precision deuterium background obtained where ratio,to the so kaonic signal for improved hydrogen, is experiments, expected an towith other good be energy experimental 10 and technique times timing smaller resolution, hadoperated high as to in counting compared the rate be radiation capability developed: and environment of enoughDrift soft-x-ray robustness an Detectors to for detectors accelerator. be Hadronic This Atom is Research the by SIDDHARTA Timing project Application) (Silicon showers from lost beam particles aswith was the seen nearly in back-to-back DEAR, emitted by chargedPractically demanding kaons only a (See charged coincidence fig. kaon of correlated 3) the background we X-ray will will remain. get much cleaner spectra. Figure 2: interaction through ionization and excitation of thethe atoms and electron, molecules in and eventually an isCoulomb captured, deexcitation, excited scattering) replacing the orbit kaonic atom (n deexciteslow-n to state lower with states. small When angular a momentum, kaon strong reaches interactionThe a with strong the interaction nucleus is causes the its reason absorption. forelectromagnetic a values shift and in the the finite energies lifetime of oflevel the the width. low-lying state levels corresponds from to the an purely increase in the observed Kaonic X-rays 2. Experimental program We will use 216 cm PoS(KAON)037 Michael Cargnelli 4 Scheme of the triggered detection system for kaonic X-rays. The planned SIDDHARTA setup, 3d view, drawing, photo of SDD . This first-time-ever result and a renewed measurement of kaonic hydrogen 1 − Figure 3: Figure 4: We will use a cryogenic gas target with about 0.03 of liquid hydrogen density. An overview of The kaonic atom experimental program using these SDDs will be starting at LNFrascati in with greatly improved precision will allow to feed the low energy QCD descriptions with precise the setup is shown in fig.4.precision A for simulation extracting of the the shift expected and signalluminosity width and of of 600 background kaonic pb and deuterium the are shown obtainable in fig.5 for an integrated 2007 with test measurements. electron generated in this volume hasthe to anode fall in down the to center the ofindependent point the front of of side. lowest the potential The detector energy, small which value area)signal. is of results the Compared anode in to capacitance conventional a (which photodiodes large isand the almost amplitude yield SDDs a and can much a be better operated short energy at resolution. rise higher time counting of rates the output Kaonic X-rays PoS(KAON)037 Michael Cargnelli ] lower graph. 10 5 ] upper graph, from [ 5 Monte Carlo simulation of the kaonic deuterium experiment, assuming background intensities as A.N. Ivanov et al., Eur. Phys. J. A23,E. 79-111 Gatti (2005). and P. Rehak, Nucl. Inst. andwww.lnf.infn.it Meth. > A Nuclear 225, Physics 608 > (1984). SIDDHARTA >states Letter at of DAFNE2 Intent - - Amadeus Study collaboration of deeply bound nuclear Y. Akaishi and T. Yamazaki, Phys. Rev. C 65,A.N. 44005 Ivanov (2002). et al., Eur. Phys. J. A25 329 (2005). A.N. Ivanov et al., J. Phys. G31 (2005) 769. G. Beer et al. [DEAR Collaboration], Phys. Rev.B. Lett. Borasoy, 94, R. 212302 Nißler, (2005). and W. Weise, Phys. Rev.U.-G. Lett. Meißner, 94, U. 213401 Raha, (2005). and A. Rusetsky, Eur. Phys.U.-G. J. Meißner, U. C35, Raha, 349 and (2004). A. Rusetsky, Eur. Phys.J.A. J. Oller, J. C47, Prades, 473 and (2006). M. Verbeni, Phys.S. Rev. Lett. Deser 95 et 172502 al., (2005) Phys. Rev. 96, 774 (1954) 774; T.L. Trueman, Nucl.Phys. 26, 57 (1961) 57. M. Iwasaki et al. [KpX Collaboration],Collaboration], Phys. Phys. Rev. Rev. Lett. C58 78 (1998) (1997) 2366. 3067; T.M. Ito et al. [KpX [6] [7] [8] [9] [2] [3] [4] [5] [1] [11] [12] [10] References Figure 5: measured in DEAR. Note the1:1. good Input background for suppression shift resulting and in width: a from signal/background [ ratio of about Kaonic X-rays data and allow a stringent test of the understanding of chiral symmetry breaking.