We present the first search for the lepton-flavor-violating decay modes B0→KS0τ±ℓ∓ (ℓ=μ,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 τ decays to either light leptons, one charged hadron, or one charged hadron and a neutral pion. We find no evidence for B0→KS0τ±ℓ∓ decays and set 90% confidence level upper limits on the branching fractions in the range of [0.8,3.6]×10-5.
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2025). Search for Lepton-Flavor-Violating Decay Modes B0→KS0τ±ℓ∓ with Hadronic B Tagging at Belle and Belle II. PHYSICAL REVIEW LETTERS, 135(4), 041801-1-041801-8 [10.1103/yzvh-v3hm].
Search for Lepton-Flavor-Violating Decay Modes B0→KS0τ±ℓ∓ with Hadronic B Tagging at Belle and Belle II
Branchini, P.Membro del Collaboration Group
;Budano, A.Membro del Collaboration Group
;Bussino, S.Membro del Collaboration Group
;De Pietro, G.Membro del Collaboration Group
;Laurenza, M.Membro del Collaboration Group
;Martellini, C.Membro del Collaboration Group
;Martini, A.Membro del Collaboration Group
;
2025-01-01
Abstract
We present the first search for the lepton-flavor-violating decay modes B0→KS0τ±ℓ∓ (ℓ=μ,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 τ decays to either light leptons, one charged hadron, or one charged hadron and a neutral pion. We find no evidence for B0→KS0τ±ℓ∓ decays and set 90% confidence level upper limits on the branching fractions in the range of [0.8,3.6]×10-5.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


