{"paper":{"title":"Pion pair production in $e^+e^-$ annihilation","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Ivan Schmidt, Zhun Lu","submitted_at":"2006-03-20T22:02:53Z","abstract_excerpt":"We present an analysis of the process $e^+e^-\\to V^*\\to\\pi\\pi\\gamma$, where $V=\\gamma$ or $V=Z$ boson, in the kinematical region where $\\sqrt{s}$, the c.m. energy of the $e^+e^-$ pair, is large but much below the $Z$-pole. The subprocess $V^*\\to \\pi\\pi \\gamma$ can be described by the convolution of the hard scattering coefficient $V\\to q \\bar{q} \\gamma$ and the general distribution amplitude of two pions $q\\bar{q}\\to \\pi \\pi$. In the case of neutral pion production, $V=\\gamma$ is the dominant process, which can therefore be used to access the GPAs of the pion, especially their $C$-even parts. "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/0603151","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"}