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Evidence for $\pi K$-atoms with DIRAC (2009) |
- Adeva, B.,
- Afanasyev, L.,
- Allkofer, Y.,
- Amsler, C.,
- Anania, A.,
- Benelli, A.,
- Brekhovskikh, V.,
- Caragheorgheopol, G.,
- Cechak, T.,
- Chiba, M.,
- Chliapnikov, P.,
- Ciocarlan, C.,
- Constantinescu, S.,
- Curceanu, C.,
- Detraz, C.,
- Dreossi, D.,
- Drijard, D.,
- Dudarev, A.,
- Duma, M.,
- Dumitriu, D.,
- Fungueiriño, J. L.,
- Gerndt, J.,
- Gorin, A.,
- Gorchakov, O.,
- Gritsay, K.,
- Guaraldo, C.,
- Gugiu, M.,
- Hansroul, M.,
- Hons, Z.,
- Horikawa, S.,
- Iliescu, M.,
- Karpukhin, V.,
- Kluson, J.,
- Kobayashi, M.,
- Komarov, V.,
- Kruglov, V.,
- Kruglova, L.,
- Kulikov, A.,
- Kuptsov, A.,
- Kurochkin, I.,
- Lamberto, A.,
- Lanaro, A.,
- Lapshin, V.,
- Lednicky, R.,
- Sandri, P. Levi,
- Aguera, A. Lopez,
- Lucherini, V.,
- Manuilov, I.,
- Mariñas, C.,
- Nemenov, L.,
- Nikitin, M.,
- Okada, K.,
- Olchevskii, V.,
- Pentia, M.,
- Penzo, A.,
- Pló, M.,
- Rappazzo, G. F.,
- Regenfus, C.,
- Rochet, J.,
- Romero, A.,
- Ronjin, V.,
- Ryazantsev, A.,
- Rykalin, V.,
- Saborido, J.,
- Schacher, J.,
- Sidorov, A.,
- Smolik, J.,
- Sugimoto, S.,
- Takeutchi, F.,
- Tarasov, A.,
- Tauscher, L.,
- Trojek, T.,
- Trusov, S.,
- Utkin, V.,
- Doce, O. Vázquez,
- Vrba, T.,
- Yazkov, V.,
- Yoshimura, Y.,
- Zhabitsky, M.,
- Zrelov, P.
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Abstract |
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We present evidence for the first observation of electromagnetically bound $\pi^\pm K^\mp$-pairs ($\pi K$-atoms) with the DIRAC experiment at the CERN-PS. The $\pi K$-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the $\pi^\pm$ and $K^\mp$-mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 $\pm$ 54 $\pi K$-atoms. The mean life of $\pi K$-atoms is related to the s-wave $\pi K$-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level..
Comment: 15 pages, 9 figures |
Publication details |
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