We present a search for the rare flavor-changing neutral-current decay B0→K∗0τ+τ- with data collected by the Belle II experiment at the SuperKEKB electron-positron collider. The analysis uses a 365 fb-1 data sample recorded at the center-of-mass energy of the ϒ(4S) resonance. One of the B mesons produced in the ϒ(4S)→B0B¯0 process is fully reconstructed in a hadronic decay mode, while its companion B meson is required to decay into a K∗0 and two τ leptons of opposite charge. The τ leptons are reconstructed in final states with a single electron, muon, charged pion or charged ρ meson, and additional neutrinos. We set an upper limit on the branching fraction of B(B0→K∗0τ+τ-)<1.8×10-3 at the 90% confidence level, which is the most stringent constraint reported to date.
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2025). Search for B0→K*0τ+τ− Decays at the Belle II Experiment. PHYSICAL REVIEW LETTERS, 135(15), 151801-1-151801-8 [10.1103/v1q3-9dy8].
Search for B0→K*0τ+τ− Decays at the Belle II Experiment
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 a search for the rare flavor-changing neutral-current decay B0→K∗0τ+τ- with data collected by the Belle II experiment at the SuperKEKB electron-positron collider. The analysis uses a 365 fb-1 data sample recorded at the center-of-mass energy of the ϒ(4S) resonance. One of the B mesons produced in the ϒ(4S)→B0B¯0 process is fully reconstructed in a hadronic decay mode, while its companion B meson is required to decay into a K∗0 and two τ leptons of opposite charge. The τ leptons are reconstructed in final states with a single electron, muon, charged pion or charged ρ meson, and additional neutrinos. We set an upper limit on the branching fraction of B(B0→K∗0τ+τ-)<1.8×10-3 at the 90% confidence level, which is the most stringent constraint reported to date.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
