Aad, G.Abbott, B.Beddall, Andrew JohnÇetin, Serkant AliÖztürk, SertaçŞimşek, Sinem2025-04-182025-04-182024Aad, G., Aakvaag, E., Abbott, B., Abeling, K., Abicht, N. J., Abidi, S. H., ... & Baines, J. T. (2024). Search for Nearly Mass-Degenerate Higgsinos Using Low-Momentum Mildly Displaced Tracks in pp Collisions at s= 13 TeV with the ATLAS Detector. Physical review letters, 132(2401.14046).00319007http://dx.doi.org/10.1103/PhysRevLett.132.221801https://hdl.handle.net/20.500.12713/7198Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is Formula Presented. This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using Formula Presented of proton-proton collision data at Formula Presented collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from 0.3 to 0.9 GeV is excluded at 95% confidence level, with a maximum reach of approximately 170 GeV in the Higgsino mass.eninfo:eu-repo/semantics/openAccessArticle13222124WOS:0012718511000012-s2.0-85196807349Q110.1103/PhysRevLett.132.221801Q1