{"paper":{"title":"Observation of Strong $\\phi$-meson Directed Flow at High Baryon Density","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":["hep-ex","nucl-th"],"primary_cat":"nucl-ex","authors_text":"The STAR Collaboration","submitted_at":"2026-06-04T04:21:39Z","abstract_excerpt":"We report the first observation of a large directed flow ($v_1$) of $\\phi$ mesons in mid-central Au+Au collisions at $\\sqrt{s_{\\mathrm{NN}}}=3.0$-4.5 GeV, together with the $\\sqrt{s_{\\mathrm{NN}}}=7.7$ GeV collider-energy result for the collision-energy dependence, measured by the STAR experiment at RHIC. Despite its mesonic nature, the $\\phi$-meson $v_{1}$ exhibits a magnitude comparable to that of protons and $\\Lambda$ baryons, and is significantly larger (by a factor of $\\gtrsim3$) than that of $K^0_S$ mesons at the lowest energies. The midrapidity slope $dv_1/dy$ shows a pronounced energy "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.05694","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/2606.05694/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"}