{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"2f1cf22a893f2ad512c95171b504a4ea46d393f2c61f992a7388028990858ce6","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5713935226206badad55efaef2ace77306bd0d0aa0e0c96c87ecb383f9234ddb","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"aaeb8b81acee310466dae762af3fad9bae7b3b3626f2fd1a1c0aeed8a2c6b3fd","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"qft.massless-bootstrap.large-n-pion-kink","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Bounds on how massless pions can scatter when the number of colors is large show a sharp corner. Whether QCD with many colors lies exactly at that corner is unknown.","posed_since":"2022","precise":"Albert and Rastelli (JHEP 08 (2022) 151) bounded ratios of chiral-Lagrangian Wilson coefficients for massless pions in large-N confining gauge theories, using tree-level meson exchange, crossing, unitarity and Regge behavior, and found a kink on the exclusion boundary. Determine whether the large-N QCD values of these ratios (from lattice QCD at large N or other controlled methods) coincide with the kink, and what meson spectrum the extremal amplitude has.","problem_ref":"5713935226206badad55efaef2ace77306bd0d0aa0e0c96c87ecb383f9234ddb","references":"","settled_by":"Large-N lattice determination of the relevant Wilson-coefficient ratios compared with the kink location.","status_note":"Albert and Rastelli (2022) raised and critically examined the identification; Albert, Henriksson, Rastelli and Vichi (arXiv:2312.15013, 2023) found, under a spin-2 spectral assumption, an extremal amplitude with an apparent Regge trajectory close to real meson masses; no large-N lattice comparison settles it as of 2026.","title":"Does large-N QCD lie at the pion bootstrap kink?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"cbf79bee587ecdc89affe04734738808617665f35d74a71c28d79daaab81d847","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"70811e9f7c37864be1b1900e3ea16b9ef6e494834c9b17d9be1e15c60724d384","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"3TK-wyByxykOh0Kq-7ewBbsmsx7oiLF0e27K6l28-9Ipc3jOQA55A0uhMC9s5-VucXt2Wc1YeC8DB0X1XQUDBg"},"schema":"pubphys.envelope/1"},"record_hash":"cbf79bee587ecdc89affe04734738808617665f35d74a71c28d79daaab81d847","leaf_index":3654}