Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length

DIRAC Collaboration; B. Adeva; L. Afanasyev; Y. Allkofer; C. Amsler; A. Anania; S. Aogaki; A. Benelli; V. Brekhovskikh; T. Cechak; M. Chiba; P. Chliapnikov; D. Drijard; A. Dudarev; D. Dumitriu; P. Federicova; D. Fluerasu; A. Gorin; O. Gorchakov; K. Gritsay; C. Guaraldo; M. Gugiu; M. Hansroul; Z. Hons; S. Horikawa; Y. Iwashita; V. Karpukhin; J. Kluson; M. Kobayashi; V. Kruglov; L. Kruglova; A. Kulikov; E. Kulish; A. Kuptsov; A. Lamberto; A. Lanaro; R. Lednicky; C. Marinas; J. Martincik; L. Nemenov; M. Nikitin; K. Okada; V. Olchevskii; M. Pentia; A. Penzo; M. Plo; P. Prusa; G. Rappazzo; A. Romero Vidal; A. Ryazantsev; V. Rykalin; J. Saborido; J. Schacher; A. Sidorov; J. Smolik; F. Takeutchi; L. Tauscher; T. Trojek; S. Trusov; T. Urban; T. Vrba; V. Yazkov; Y. Yoshimura; M. Zhabitsky; P. Zrelov

doi:10.1103/physrevd.96.052002

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arXiv · 1707.02184

Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length

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Abstract

After having announced the statistically significant observation (5.6~$\sigma$) of the new exotic $\pi K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $\pi K$ data sample: $\tau = (5.5^{+5.0}_{-2.8}) \cdot 10^{-15}s$. By means of a precise relation ($<1\%$) between atom lifetime and scattering length, the following value for the S-wave isospin-odd $\pi K$ scattering length $a_0^{-}~=~\frac{1}{3}(a_{1/2}-a_{3/2})$ has been derived: $\left|a_0^-\right| = (0.072^{+0.031}_{-0.020}) M_{\pi}^{-1}$.

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DIRAC Collaboration, B. Adeva, L. Afanasyev, Y. Allkofer, C. Amsler, A. Anania, S. Aogaki, A. Benelli, V. Brekhovskikh, T. Cechak, M. Chiba, P. Chliapnikov, D. Drijard, A. Dudarev, D. Dumitriu, P. Federicova, D. Fluerasu, A. Gorin, O. Gorchakov, K. Gritsay, C. Guaraldo, M. Gugiu, M. Hansroul, Z. Hons, S. Horikawa, Y. Iwashita, V. Karpukhin, J. Kluson, M. Kobayashi, V. Kruglov, L. Kruglova, A. Kulikov, E. Kulish, A. Kuptsov, A. Lamberto, A. Lanaro, R. Lednicky, C. Marinas, J. Martincik, L. Nemenov, M. Nikitin, K. Okada, V. Olchevskii, M. Pentia, A. Penzo, M. Plo, P. Prusa, G. Rappazzo, A. Romero Vidal, A. Ryazantsev, V. Rykalin, J. Saborido, J. Schacher, A. Sidorov, J. Smolik, F. Takeutchi, L. Tauscher, T. Trojek, S. Trusov, T. Urban, T. Vrba, V. Yazkov, Y. Yoshimura, M. Zhabitsky, P. Zrelov. 2017-07-07. Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length. https://doi.org/10.1103/physrevd.96.052002

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