| Article | |
| Report number | arXiv:1508.04712 ; CERN-PH-EP-2015-175 ; DIRAC-PUB-2015-02 ; CERN-PH-EP-2015-175 |
| Title | First observation of long-lived $\pi^+ \pi^-$ atoms |
| Author(s) |
Adeva, B (U. Santiago de Compostela (main)) ; Afanasyev, L (Dubna, JINR) ; Anania, A (INFN, Trieste ; U. Messina (main)) ; Aogaki, S (Bucharest, IFIN-HH) ; Benelli, A (CTU, Prague) ; Brekhovskikh, V (Serpukhov, IHEP) ; Cechak, T (CTU, Prague) ; Chiba, M (Tokyo Metropolitan U. (main)) ; Chliapnikov, P (Serpukhov, IHEP) ; Doskarova, P (CTU, Prague) ; Drijard, D (CERN) ; Dudarev, A (Dubna, JINR) ; Duma, M (Bucharest, IFIN-HH) ; Dumitriu, D (Bucharest, IFIN-HH) ; Fluerasu, D (Bucharest, IFIN-HH) ; Gorin, A (Serpukhov, IHEP) ; Gorchakov, O (Dubna, JINR) ; Gritsay, K (Dubna, JINR) ; Guaraldo, C (Frascati) ; Gugiu, M (Bucharest, IFIN-HH) ; Hansroul, M (CERN) ; Hons, Z (Rez, Nucl. Phys. Inst.) ; Horikawa, S (U. Zurich (main)) ; Iwashita, Y (Kyoto U. (main)) ; Karpukhin, V (Dubna, JINR) ; Kluson, J (CTU, Prague) ; Kobayashi, M (KEK, Tsukuba) ; Kruglov, V (Dubna, JINR) ; Kruglova, L (Dubna, JINR) ; Kulikov, A (Dubna, JINR) ; Kulish, E (Dubna, JINR) ; Kuptsov, A (Dubna, JINR) ; Lamberto, A (INFN, Trieste ; U. Messina (main)) ; Lanaro, A (U. Wisconsin, Madison (main)) ; Lednicky, R (Prague, Inst. Phys.) ; Marinas, C (U. Santiago de Compostela (main)) ; Martincik, J (CTU, Prague) ; Nemenov, L (Dubna, JINR ; CERN) ; Nikitin, M (Dubna, JINR) ; Okada, K (Kyoto Sangyo U.) ; Olchevskii, V (Dubna, JINR) ; Ovsiannikov, V (Voronezh State U.) ; Pentia, M (Bucharest, IFIN-HH) ; Penzo, A (INFN, Trieste) ; Plo, M (U. Santiago de Compostela (main)) ; Prusa, P (CTU, Prague) ; Rappazzo, G (INFN, Trieste ; U. Messina (main)) ; Romero Vidal, A (U. Santiago de Compostela (main)) ; Ryazantsev, A (Serpukhov, IHEP) ; Rykalin, V (Serpukhov, IHEP) ; Saborido, J (U. Santiago de Compostela (main)) ; Schacher, J (Bern U., LHEP) ; Sidorov, A (Serpukhov, IHEP) ; Smolik, J (CTU, Prague) ; Takeutchi, F (Kyoto Sangyo U.) ; Tauscher, L (Basel U. (main)) ; Trojek, T (CTU, Prague) ; Trusov, S (SINP, Moscow) ; Urban, T (CTU, Prague) ; Vrba, T (CTU, Prague) ; Yazkov, V (SINP, Moscow) ; Yoshimura, Y (KEK, Tsukuba) ; Zhabitsky, M (Dubna, JINR) ; Zrelov, P (Dubna, JINR) |
| Publication | 2015-09-26 |
| Imprint | 30 Jun 2015 |
| Number of pages | 13 |
| Note | 13 pages, 7 figures |
| In: | Phys. Lett. B 751 (2015) 12-18 |
| DOI | 10.1016/j.physletb.2015.09.060 |
| Subject category | Detectors and Experimental Techniques ; Nuclear Physics - Experiment ; Particle Physics - Experiment |
| Accelerator/Facility, Experiment | CERN PS ; DIRAC PS212 |
| Free keywords | QCD ; lifetime ; experimental results |
| Abstract | After observing and investigating the double-exotic $\pi^+\pi^-$ atom with the ground state lifetime $\tau$ of about $3 \times 10^{-15}$ s, the upgraded DIRAC experiment at the CERN PS accelerator observes for the first time long-lived states of the same atom with lifetimes of about $10^{-11}$ s and more. The number of characteristic pion pairs resulting from the breakup (ionisation) of long-lived $\pi^+\pi^-$ atoms amounts to $436\pm61$, corresponding to a signal-to-error ratio of better than 7 standard deviations. This observation opens a new possibility to measure energy differences between $p$ and $s$ atomic states and so to determine $\pi \pi$ scattering lengths. |
| Copyright/License | preprint: © 2015-2024 CERN (License: arXiv nonexclusive-distrib. 1.0) publication: © 2015-2024 CERN (License: CC-BY-4.0), sponsored by SCOAP³ |
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Записът е създаден на 2015-08-20, последна промяна на 2023-03-14
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