{"paper":{"title":"First measurement of a long-lived $\\pi^+ \\pi^-$ atom lifetime","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["nucl-ex"],"primary_cat":"hep-ex","authors_text":"A.Anania, A.Benelli, A.Dudarev, A.Gorin, A.Kulikov, A.Lamberto, A.Lanaro, A.Penzo, A.Romero Vidal, A.Ryazantsev, A.Sidorov, B.Adeva, C.Guaraldo, C.Mari\\~nas, D.Drijard, D.Dumitriu, D.Fluerasu, E.Kulish, F.Takeutchi, G.F.Rappazzo, J.Kluson, J.Martincik, J.Saborido, J.Schacher, J.Smolik, K.Gritsay, K.Okada, L.Afanasyev, L.Kruglova, L.Nemenov, M.Chiba, M.Gugiu, M.Hansroul, M.Kobayashi, M.Nikitin, M.Pentia, M.Plo, O.Gorchakov, P.Doskarova, P.Prusa, P.V.Chliapnikov, P.Zrelov, R.Lednicky, S.Aogaki, S.Horikawa, S.Trusov, T.Cechak, T.Trojek, T.Vrba, V.Brekhovskikh, V.Karpukhin, V.Kruglov, V.Olchevskii, V.Ovsiannikov, V.Rykalin, V.Yazkov, Y.Iwashita, Y.Yoshimura, Z.Hons","submitted_at":"2018-11-21T10:07:44Z","abstract_excerpt":"The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $\\pi^+\\pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\\textmu{}m thick platinum foil. Analysing the observed number of atomic pairs, $n_A^L= \\left.436^{+157}_{-61}\\right|_\\mathrm{tot}$, the lifetime of the 2$p$ state is found to be ${\\tau_{2p}=(\\left.0.45^{+1.08}_{-0.30}\\right|_\\mathrm{tot}) \\cdot10^{-11}}$s, not contradicting the corresponding QED $2p$ state lifetime ${\\tau_{2p}^\\mathrm{QED}=1.17 "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1811.08659","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}