{"arxiv_id":"hep-ph/0312067","title":"The triple collinear limit of one-loop QCD amplitudes","abstract":"We consider the singular behaviour of one-loop QCD matrix elements when several external partons become simultaneously parallel. We present a new factorization formula that describes the singular collinear behaviour directly in colour space. The collinear singularities are embodied in process-independent splitting matrices that depend on the momenta, flavours, spins and colours of the collinear partons. We give the general structure of the infrared and ultraviolet divergences of the one-loop splitting matrices. We also present explicit one-loop results for the triple collinear splitting, $q \\to q {\\bar Q} Q$, of a quark and a quark--antiquark pair of different flavours. The one-loop triple collinear splitting is one of the ingredients that can be used to compute the evolution of parton distributions at the next-to-next-to-leading order in QCD perturbation theory.","primary_cat":"hep-ph","cross_cats":[],"submitted_at":"2003-12-04T17:09:39+00:00","latest_version":2,"source":"arxiv","source_label":"arXiv","source_url":null,"has_pdf":true,"has_source":false,"verdict":"CONDITIONAL","confidence":"MODERATE","one_line_summary":"A colour-space factorization formula and an explicit one-loop result are given for the triple collinear limit q -> q Qbar Q of QCD amplitudes.","novelty_score":7.0,"correctness_risk":"medium","formal_verification":"none","upvotes":0,"downvotes":0,"pith_score":0.0,"inbound_count":26,"_links":{"html":"https://pith.science/paper/hep-ph/0312067","verdict":"/api/v1/verdicts/hep-ph/0312067"}}