The strong interaction of antikaons (K−) with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open ...questions like the question of antikaon nuclear bound states - the prototype system being K−pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAΦNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K−p atom leading to a hadronic shift ϵ1s and a hadronic broadening Γ1s of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated constrained by the SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent scattering lengths a measurement of the hadronic shift and width of kaonic deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2). Many improvements in the experimental setup will allow to measure kaonic deuterium which is challenging due to the anticipated low X-ray yield. Especially important are the data on the X-ray yields of kaonic deuterium extracted from a exploratory experiment within SIDDHARTA.
The first measurement of the yields of three kaonic nitrogen X-ray transitions, using the DEAR (DAΦNE Exotic Atom Research) setup at the DAΦNE collider of Frascati, is reported. The yields are ...41.5±8.7(stat.)±4.1(sys.)% for the n=7→6 transition, 55.0±3.9(stat.)±5.5(sys.)% for the n=6→5 transition and 57.4±15.2(stat.)±5.7(sys.)% for the n=5→4 transition at a density ρ=3.4ρNTP. By using the experimental yields in an atomic cascade calculation, a 1 to 3% K-shell electron population in the n=6 level was deduced.
In the exotic atoms in which one electron is replaced by a negatively charged kaon, the kaon-nucleus hadronic interaction introduces an energy shift and broadening of the low-lying states of the ...kaonic atoms. The shift and width can be determined with high precision from the atomic x-ray spectroscopy, and this experimental method provides unique information to understand the low energy kaon-nucleus interaction at the production threshold.
The AMADEUS collaboration studies low-energy K− interactions with light nuclei in order to clarify some aspects related to the behaviour of hadrons containing strangeness in nuclear medium. One of ...the main topics is the quest about the possible formation of Kaonic Nuclear Clusters (KNC), which depends on the strength of the anti-kaons interaction with nucleons. In kaonic absorption experiments, the search for KNC is strictly connected with the measurement of the yields of the so-called multi-nucleon absorption processes. In this paper, the study of Σ0p correlated production from K− absorption in 12C, using the KLOE 2004-2005 data set, is reported. The yield of the two nucleon absorption (2NA), when the produced Σ0 and p particles are free from any final state interaction process, was measured for the first time. The contribution of a ppK− bound state was also tested. The best fit is obtained for a ppK− state with a binding energy of 45 MeV and a width of 30 MeV, but the statistical significance is at the level of 1σ only.
In the last decades huge theoretical effort was devoted to the development of consistent theoretical models, aiming to solve the so-called "measurement problem". Among these, the Dynamical Reduction ...Models possess the unique characteristic to be experimentally testable, thus enabling to set experimental upper bounds on the reduction rate parameter λ characterizing these models. By analysing the X-ray spectrum emitted by an isolated slab of Germanium, we set the most stringent limit on the λ parameter up to date.
New analysis method for CCD X-ray data Ishiwatari, T.; Beer, G.; Bragadireanu, A.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2006, Letnik:
556, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The analysis method developed for kaonic nitrogen X-ray data obtained at the DA
Φ
NE electron–positron collider of Frascati National Laboratories using Charge-Coupled Devices (CCDs) in the DEAR ...experimental setup is described. Background events could be highly rejected by this analysis procedure. Three sequential X-ray lines from kaonic nitrogen transitions, showing good energy resolution, could be clearly identified, and the yields measured for the first time.
The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DAΦNE collider at LNF-INFN, fundamental to respond to longstanding open questions in the ...non-perturbative QCD in the strangeness sector. One of the most interesting aspects is to understand how hadron masses and interactions change in the nuclear environment. The antikaon-nucleon potential is investigated searching for signals from possible bound kaonic clusters, which would imply a strongly attractive antikaon-nucleon potential. AMADEUS step 0 consists in the analysis of 2004/2005 KLOE data, exploring K− absorptions in H, 4He, 9Be and 12C present in setup materials. The status of the various preliminary analyses is presented, together with future perspectives.
The interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field in hadron physics with still many important open questions. The investigation of ...light kaonic atoms is, in this context, a unique tool to obtain precise information on this interaction. The most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium, were carried out by the SIDDHARTA Collaboration at the DAΦNE electron–positron collider of LNF-INFN, by combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and precise Silicon-Drift X-ray detectors. The measurement of kaonic deuterium will be realized in the near future by SIDDHARTA-2, a major upgrade of SIDDHARTA.
X-ray spectroscopy of light kaonic atoms is a unique tool to provide precise information on the fundamental K̄N interaction at the low-energy limit and the in-medium nuclear interaction of K−. The ...future experiments of kaonic deuterium strong-interaction shift and width (SIDDHARTA-2 and J-PARC E57) can extract the isospin dependent K−N interaction at threshold. The high-resolution X-ray spectroscopy of kaonic helium with microcalorimeters (J-PARC E62) has the possibility to solve the long-standing potential-strength problem of the attractive K−-nucleus interaction. Here, the recent experimental results and the future projects of X-ray spectroscopy of light kaonic atoms are presented.
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