{"paper":{"title":"Study of a Narrow pi+ pi- Peak at about 755 MeV/c**2 in pbar n --> 2 pi+ 3 pi- Annihilation at Rest","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"Mario Gaspero","submitted_at":"2010-05-13T17:48:03Z","abstract_excerpt":"A narrow peak in the pi+ pi- mass distribution was seen by the Rome-Syracuse Collaboration in pbar n --> 2 pi+ 3 pi- annihilation at rest in 1970.  It was ignored for 40 years.  The reanalysis of this peak finds that it has the mass 757.4 +- 2.8_stat +- 1.1_sys MeV/c**2 and a width consistent with the experimental resolution.  The evidence of the peak is 5.2 standard deviations.  The peak is generated in (1.03 +- 0.21_stat +- 0.21_sys)% of the pbar n annihilations at rest.  No spin analysis is possible with the statistics of the experiment but there are arguments suggesting that it has JP = 0+"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1005.2381","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"}