{"paper":{"title":"Non-uniqueness of restitution coefficients in oblique impacts of discs, even in cases of unique normal restitution","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.soft","authors_text":"Dominik Krengel","submitted_at":"2026-08-07T00:44:55Z","abstract_excerpt":"We investigate the different coefficients of restitution $e$ of a dissipative, frictional disc as a function of the impact angle $\\theta$ and the friction coefficient $\\mu$. We observe a non-monotonic, non-linear behaviour of $e_{\\mathrm{T}}$ and $e_{\\mathrm{kin}}$ with a clear minimum at $\\mu$-dependent values of $\\theta$ and a convergence for all $\\mu$ at large $\\theta$, bounded by the cases of pure rolling and pure sliding. Changing the dissipative normal interaction affects the $\\mu$ convergence at large $\\theta$ and leads to a convergence at low $\\theta$. The presence of initial angular v"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.06675","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/2608.06675/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"}