{"paper":{"title":"Joint Multi-Period Fermi-LAT and LHAASO Constraints on Axion-Like Particles from Mrk 421 Using Profile Likelihood with Gaussian Copula Correlation","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Ao Wang, Chuyuan Yang, Guangbo Long, Huaizhen Li, Hushan Xu, Jiancheng Wang, Longhua Qin, Weiwei Na, Xiaogu Zhong, Yubin Li, Zunli Yuan","submitted_at":"2026-06-04T06:04:09Z","abstract_excerpt":"We construct a multi-epoch joint profile-likelihood framework to constrain axion-like particles (ALPs), employing a Gaussian copula ($\\rho=0.03$) to account for weak correlations among distinct observational periods. Different from traditional independent likelihood addition, our scheme globally optimizes nuisance parameters under the no-ALP hypothesis prior to profiling ALP mass $m_a$ and coupling $g_{a\\gamma}$, enhancing numerical stability and statistical consistency. Using five sets of simultaneous Fermi-LAT and LHAASO data of Mrk 421, we implement both two-zone hybrid and single-zone hadr"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.05738","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/2606.05738/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"}