Hayrapetyan, A.Tumasyan, A.Adam, W.Andrejkovic, J. W.Bergauer, T.Chatterjee, S.Damanakis, K.2026-04-252026-04-2520250031-90071079-7114https://doi.org/10.1103/PhysRevLett.134.131802https://hdl.handle.net/11486/8428A search is presented for fractionally charged particles with charges below 1e, using their small energy loss in the tracking detector as a key variable to observe a signal. The analyzed dataset corresponds to an integrated luminosity of 138 fb(-1) of proton-proton collisions collected at root s = 13 TeV in 2016-2018 at the CERN LHC. This is the first search at the LHC for new particles with a charge between e/3 and 0.9e, including an extension of previous results at a charge of 2e/3. Masses up to 640 GeV and charges as low as e/3 are excluded at 95% confidence level. These are the most stringent limits to date for the considered Drell-Yan-like production mode.eninfo:eu-repo/semantics/openAccessArticle1341310.1103/PhysRevLett.134.131802402503892-s2.0-105003767734Q1WOS:001498371200001Q10000-0003-3249-92080000-0003-0392-86910000-0001-9726-49150000-0003-2898-69000000-0002-0793-56640009-0005-9590-99580000-0003-1124-8450