We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| from the decay B → Dℓνℓ using a 365 fb-1 e+e- → ϒ(4S) → BB¯ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one B meson is reconstructed in the modes B0 → D−(→ K+π−π−)ℓ+νℓ and B+ → D¯0( → K+π−)ℓ+νℓ, where ℓ denotes either an electron or a muon. Charge conjugation is implied. The second B meson in the ϒ(4S) event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable w = vB·vD, where vB and vD are the four-velocities of the B and D mesons. We measure the total decay branching fractions to be B(B0 → D−ℓ+νℓ) = (2.06 ± 0.05(stat) ± 0.10(sys))% and B(B+ → D¯0ℓ+νℓ) = (2.31 ± 0.04(stat) ± 0.09(sys))%. We probe lepton flavor universality by measuring B(B → Deνe)/B(B → Dμνμ) = 1.020 ± 0.020(stat) ± 0.022(sys). Fitting the partial decay branching fraction as a function of w and using the average of lattice QCD calculations of the B → D form factor, we obtain |Vcb| = (39.2 ± 0.4(stat) ± 0.6(sys) ± 0.5(th)) × 10−3.
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Ahn, Y., Aihara, H., et al. (2025). Determination of |V cb| using B → D ℓ νl decays at Belle II. PHYSICAL REVIEW D, 112(11), 112009-1-112009-15 [10.1103/vs8k-259v].
Determination of |V cb| using B → D ℓ νl decays at 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
;Salutari, L.Membro del Collaboration Group
;
2025-01-01
Abstract
We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| from the decay B → Dℓνℓ using a 365 fb-1 e+e- → ϒ(4S) → BB¯ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one B meson is reconstructed in the modes B0 → D−(→ K+π−π−)ℓ+νℓ and B+ → D¯0( → K+π−)ℓ+νℓ, where ℓ denotes either an electron or a muon. Charge conjugation is implied. The second B meson in the ϒ(4S) event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable w = vB·vD, where vB and vD are the four-velocities of the B and D mesons. We measure the total decay branching fractions to be B(B0 → D−ℓ+νℓ) = (2.06 ± 0.05(stat) ± 0.10(sys))% and B(B+ → D¯0ℓ+νℓ) = (2.31 ± 0.04(stat) ± 0.09(sys))%. We probe lepton flavor universality by measuring B(B → Deνe)/B(B → Dμνμ) = 1.020 ± 0.020(stat) ± 0.022(sys). Fitting the partial decay branching fraction as a function of w and using the average of lattice QCD calculations of the B → D form factor, we obtain |Vcb| = (39.2 ± 0.4(stat) ± 0.6(sys) ± 0.5(th)) × 10−3.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
