{"paper":{"title":"Bounding the effect of penguin diagrams in $a_{CP}(B^0 \\to \\pi^+\\pi^-)$","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Helen R. Quinn, Yuval Grossman","submitted_at":"1997-12-08T22:14:36Z","abstract_excerpt":"A clean determination of the angle $\\alpha$ of the unitary triangle from $B\\to \\pi\\pi$ decays requires an isospin analysis. If the $B \\to \\pi^0\\pi^0$ and $\\bar B \\to \\pi^0\\pi^0$ decay rates are small it may be hard to carry out this analysis. Here we show that an upper bound on the error on $\\sin 2\\alpha$ due to penguin diagram effects can be obtained using only the measured rate $\\BR(B^\\pm \\to \\pi^\\pm \\pi^0)$ and an upper bound on the combined rate $\\BR(B \\to \\pi^0 \\pi^0) + \\BR(\\bar B \\to \\pi^0 \\pi^0)$. Since no b flavor tagging is needed to measure this combined rate, the bound that can be a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/9712306","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"}