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1.
Nucl Phys A ; 914(100): 305-309, 2013 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-24068854

RESUMO

The kaonic 3He and 4He [Formula: see text] transitions in gaseous targets were observed by the SIDDHARTA experiment. The X-ray energies of these transitions were measured with large-area silicon-drift detectors using the timing information of the [Formula: see text] pairs produced by the DAΦNE [Formula: see text] collider. The strong-interaction shifts and widths both of the kaonic 3He and 4He 2p states were determined, which are much smaller than the results obtained by the previous experiments. The "kaonic helium puzzle" (a discrepancy between theory and experiment) was now resolved.

2.
Nucl Phys A ; 907(100): 69-77, 2013 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-23805024

RESUMO

The study of the [Formula: see text] system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with [Formula: see text] and [Formula: see text], taking advantage of the low-energy charged kaons from Φ-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of [Formula: see text] and of [Formula: see text] are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: [Formula: see text] and [Formula: see text] (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.

3.
Phys Lett B ; 714(1): 40-43, 2012 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-22876000

RESUMO

The kaonic (3)He and (4)He X-rays emitted in the [Formula: see text] transitions were measured in the SIDDHARTA experiment. The widths of the kaonic (3)He and (4)He 2p states were determined to be [Formula: see text], and [Formula: see text], respectively. Both results are consistent with the theoretical predictions. The width of kaonic (4)He is much smaller than the value of [Formula: see text] determined by the experiments performed in the 70's and 80's, while the width of kaonic (3)He was determined for the first time.

4.
Phys Lett B ; 697(3-2): 199-202, 2011 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-21633519

RESUMO

The first observation of the kaonic (3)He 3d→2p transition was made, using slow K- mesons stopped in a gaseous (3)He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K- pairs of ϕ-meson decays produced by the DAΦNE e+e- collider. The strong interaction shift of the kaonic (3)He 2p state was determined to be -2±2(stat)±4(syst) eV.

5.
Phys Rev Lett ; 94(21): 212302, 2005 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-16090312

RESUMO

The DEAR (DAPhiNE exotic atom research) experiment measured the energy of x rays emitted in the transitions to the ground state of kaonic hydrogen. The measured values for the shift epsilon and the width Gamma of the 1s state due to the K(-)p strong interaction are epsilon(1s)=-193 +/- 37 (stat) +/- 6 (syst) eV and Gamma(1s)=249 +/- 111 (stat) +/- 30 (syst) eV, the most precise values yet obtained. The pattern of the kaonic hydrogen K-series lines, K(alpha), K(beta), and K(gamma), was disentangled for the first time.

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