{"paper":{"title":"$\\pi^+ \\pi^-$ and $\\pi^0 \\pi^0$ pair production in photon-photon and in ultraperipheral ultrarelativistic heavy ion collisions","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"nucl-th","authors_text":"Antoni Szczurek, Mariola K{\\l}usek-Gawenda","submitted_at":"2013-02-18T09:58:33Z","abstract_excerpt":"We discuss ${\\gamma}{\\gamma}\\to {\\pi}{\\pi}$ reactions, starting from the two-pion threshold up to about $\\sqrt{s_{{\\gamma}{\\gamma}}}$ = 6 GeV. We include the dipion continuum due to pion exchange (for ${\\pi}^+{\\pi}^-$) and ${\\rho}^\\pm$ exchange (for ${\\pi}^0{\\pi}^0$) as well as the dipion ${\\sigma}(600)$, $f_0(980)$ and $f_2(1270)$ s-channel resonances. We discuss also a possible contribution of less pronounced scalar resonances $f_0(1500)$ and $f_0(1710)$ as well as the tensor resonances $f'_2(1525)$, $f_2(1565)$ and $f_2(1950)$. We find that the inclusion of the spin-four $f_4(2050)$ resonan"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1302.4204","kind":"arxiv","version":2},"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"}