{"paper":{"title":"Small Instantons and the Post-Inflationary QCD Axion in a Special Product GUT","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO","hep-th"],"primary_cat":"hep-ph","authors_text":"Junxuan Xu, Motoo Suzuki, Shihwen Hor, Yuichiro Nakai","submitted_at":"2025-04-02T18:00:02Z","abstract_excerpt":"We present a new framework of grand unification that is equipped with an axion solution to the strong CP problem without a domain wall problem when the Peccei-Quinn (PQ) symmetry is spontaneously broken after inflation. Our grand unified theory (GUT) is based on a symmetry breaking pattern, $SU(10) \\times SU(5)_1 \\rightarrow SU(5)_V \\supset SU(3)_C \\times SU(2)_L \\times U(1)_Y$, where $SU(5)_1$ and a special embedding of $SU(5)_2\\subset SU(10)$ are broken to a diagonal subgroup $SU(5)_V$. The model contains a vector-like pair of PQ-charged fermions that transform as (anti-)fundamental represen"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2504.02033","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2504.02033/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}