We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element |𝑉𝑐⁢𝑏| from the decay 𝐵 →𝐷⁢ℓ⁢𝜈ℓ using a 365  fb−1 𝑒+⁢𝑒− →ϒ⁡(4⁢𝑆) →𝐵⁢ ¯𝐵 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+ →¯𝐷0⁡( →𝐾+⁢𝜋−)⁢ℓ+⁢𝜈ℓ, where ℓ denotes either an electron or a muon. Charge conjugation is implied. The second 𝐵 meson in the ϒ⁡(4⁢𝑆) 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+ →¯𝐷0⁢ℓ+⁢𝜈ℓ) =(2.31±0.04⁢(stat)±0.09⁢(sys))%. We probe lepton flavor universality by measuring ℬ⁡(𝐵 →𝐷⁢𝑒⁢𝜈𝑒)/ℬ⁡(𝐵 →𝐷⁢𝜇⁢𝜈𝜇) =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 |𝑉𝑐⁢𝑏| =(39.2±0.4⁢(stat)±0.6⁢(sys)±0.5⁢(th))×10−3.

Determination of |Vcb| using B -> D l nu decays at Belle II / Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Ahn, Y., Aihara, H., Akopov, N., Alghamdi, S., Alhakami, M., Aloisio, A., Amos, K., Angelsmark, M., Ky, N.A., Antonioli, C., Asner, D. m., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Ayad, R., et al.. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 112/2025:11(2025), pp. 112009.1-112009.15. [10.1103/vs8k-259v]

Determination of |Vcb| using B -> D l nu decays at Belle II

Gabrielli, A.;Ganiev, E.;Ghosh, D.;Manfredi, R.;Raiz, S.;Vitale, L.;
2025-01-01

Abstract

We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element |𝑉𝑐⁢𝑏| from the decay 𝐵 →𝐷⁢ℓ⁢𝜈ℓ using a 365  fb−1 𝑒+⁢𝑒− →ϒ⁡(4⁢𝑆) →𝐵⁢ ¯𝐵 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+ →¯𝐷0⁡( →𝐾+⁢𝜋−)⁢ℓ+⁢𝜈ℓ, where ℓ denotes either an electron or a muon. Charge conjugation is implied. The second 𝐵 meson in the ϒ⁡(4⁢𝑆) 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+ →¯𝐷0⁢ℓ+⁢𝜈ℓ) =(2.31±0.04⁢(stat)±0.09⁢(sys))%. We probe lepton flavor universality by measuring ℬ⁡(𝐵 →𝐷⁢𝑒⁢𝜈𝑒)/ℬ⁡(𝐵 →𝐷⁢𝜇⁢𝜈𝜇) =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 |𝑉𝑐⁢𝑏| =(39.2±0.4⁢(stat)±0.6⁢(sys)±0.5⁢(th))×10−3.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3123420
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