20.500.12556/RUL-178825 Search for lepton-flavor-violating decay modes $B^0 \to K^0_S \tau^{\pm}\ell^{\mp}$ with hadronic B tagging at Belle and Belle II We present the first search for the lepton-flavor-violating decay modes $B^0 \to K^0_S\tau^{\pm}\ell^{\mp}(\ell = \mu, e)$ using the 711 and 365 fb$^{-1}$ data samples recorded by the Belle and Belle II detectors, respectively. We use a hadronic $B$-tagging technique to fully reconstruct a $B$ meson and search for signal decays in the system recoiling against the tagged meson, considering $\tau$ decays to either light leptons, one charged hadron, or one charged hadron and a neutral pion. We find no evidence for $B^0 \to K^0_S\tau^{\pm}\ell^{\mp}$ decays and set 90 % confidence level upper limits on the branching fractions in the range of [0.8,3.6] × 10$^{-5}$. experimental physics physics of elementary particles particle decays eksperimentalna fizika fizika osnovnih delcev razpadi delcev true false true Angleški jezik Slovenski jezik Članek v reviji 2026-01-30 10:01:35 2026-01-30 10:01:36 2026-02-01 04:37:57 0000-00-00 00:00:00 2025 0 0 Str. 041801-1-041801-8 iss. 4 Vol. 135 Jul. 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.1 0031-9007 10.1103/yzvh-v3hm 266690819 yzvh-v3hm_(1).pdf yzvh-v3hm_(1).pdf 1 5AF0043CF23A5F81AF1A249028338F41 92bb615856c6f674deb48bbb952028c55b4702c77017c468832f7885d40273ae 277224f3-fdbc-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226829 https://journals.aps.org/prl/abstract/10.1103/yzvh-v3hm 0 307da683-fdbc-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226830 Fakulteta za matematiko in fiziko 0 0 0