@article{oai:tsukuba.repo.nii.ac.jp:00051939,
 author = {原, 和彦 and HARA, Kazuhiko and 大川, 英希 and OKAWA, Hideki and 佐藤, 構二 and SATO, Koji and 受川, 史彦 and UKEGAWA, Fumihiko and ATLA Collaboration},
 issue = {5},
 journal = {Physical review D},
 month = {Mar},
 note = {A search for four-top-quark production, t￣tt￣t, is presented. It is based on proton-proton collision data with a center-of-mass energy √s=13??TeV collected by the ATLAS detector at the Large Hadron Collider during the years 2015 and 2016, corresponding to an integrated luminosity of 36.1??fb?1. Data are analyzed in both the single-lepton and opposite-sign dilepton channels, characterized by the presence of one or two isolated electrons or muons with high-transverse momentum and multiple jets. A data-driven method is used to estimate the dominant background from top-quark pair production in association with jets. No significant excess above the Standard Model expectation is observed. The result is combined with the previous same-sign dilepton and multilepton searches carried out by the ATLAS Collaboration and an observed (expected) upper limit of 5.3 (2.1) times the four-top-quark Standard Model cross section is obtained at 95% confidence level. Additionally, an upper limit on the anomalous four-top-quark production cross section is set in the context of an effective field theory model.},
 title = {Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in pp collisions at √s=13??TeV with the ATLAS detector},
 volume = {99},
 year = {2019},
 yomi = {ハラ, カズヒコ and オオカワ, ヒデキ and サトウ, コウジ and ウケガワ, フミヒコ}
}