{"paper":{"title":"Unusual Near-horizon Cosmic-ray-like Events Observed by ANITA-IV","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"A. G. Vieregg, A. Ludwig, ANITA collaboration: P. W. Gorham, A. Novikov, A. Romero-Wolf, B. Dailey, B. D. Fox, B. F. Rauch, B. Hill, B. Rotter, B. Strutt, C. Deaconu, C. Hast, C. H. Chen, C. J. Naudet, C. Miki, D. Bhattacharya, D. Saltzberg, D. Seckel, E. Oberla, G. S. Varner, H. Schoorlemmer, J. J. Beatty, J. J. Huang, J. M. Clem, J. M. Roberts, J. Nam, J. Shiao, J. Stockham, J. W. H. Gordon, J. W. Russell, K. Belov, K. Hughes, K. McBride, L. Batten, L. Cremonesi, L. Macchiarulo, M. H. Israel, M. Olmedo, M. S. Sutherland, M. Stockham, O. Banerjee, P. Allison, P. Cao, P. Chen, P. F. Dowkontt, R. Hupe, R. J. Nichol, R. Prechelt, S. A. Wissel, S. H. Wang, S. Matsuno, S. Prohira, S. Stafford, S. Y. Hsu, T.C. Liu, V. Bugaev, W. R. Binns, Y. Chen","submitted_at":"2020-08-13T04:49:27Z","abstract_excerpt":"ANITA's fourth long-duration balloon flight in late 2016 detected 29 cosmic-ray (CR)-like events on a background of $0.37^{+0.27}_{-0.17}$ anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a characteristic phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous non-inverted polarity, a $p = 5.3 \\times 10^{-4}$ chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply-upcoming anomalous events similar to the two such events seen in prior flights."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2008.05690","kind":"arxiv","version":3},"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/2008.05690/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"}