{"paper":{"title":"Tree-level contributions to B -> Xs gamma","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Maciej Kaminski, Michal Poradzinski, Mikolaj Misiak","submitted_at":"2012-09-05T13:24:44Z","abstract_excerpt":"Weak radiative decay B -> X_s gamma is known to be a loop-generated process. However, it does receive tree-level contributions from CKM-suppressed b -> u ubar s gamma transitions. In the present paper, we evaluate such contributions together with similar ones from the QCD penguin operators. For a low value of the photon energy cutoff E_0 ~ m_b/20 that has often been used in the literature, they can enhance the inclusive branching ratio by more than 10%. For E_0 = 1.6 GeV or higher, the effect does not exceed 0.4%, which is due to phase-space suppression. Our perturbative results contain collin"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1209.0965","kind":"arxiv","version":3},"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"}