Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 2 de 2
Filter
Add more filters










Database
Language
Publication year range
1.
Phys Rev Lett ; 131(21): 211801, 2023 Nov 24.
Article in English | MEDLINE | ID: mdl-38072600

ABSTRACT

The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element V_{ub} using inclusive and exclusive decays is performed with the full Belle data set at the ϒ(4S) resonance, corresponding to an integrated luminosity of 711 fb^{-1}. We analyze collision events in which one B meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic X_{u} system of the semileptonic b→uℓν[over ¯]_{ℓ} decay. We separate exclusive B→πℓν[over ¯]_{ℓ} decays from other inclusive B→X_{u}ℓν[over ¯]_{ℓ} and backgrounds with a two-dimensional fit that utilizes the number of charged pions in the X_{u} system and the four-momentum transfer q^{2} between the B and X_{u} systems. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the B→πℓν[over ¯]_{ℓ} form factor, we determine |V_{ub}^{excl}|=(3.78±0.23±0.16±0.14)×10^{-3} and |V_{ub}^{incl}|=(3.88±0.20±0.31±0.09)×10^{-3}, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of |V_{ub}^{excl}|/|V_{ub}^{incl}|=0.97±0.12 is compatible with unity.

2.
Phys Rev Lett ; 130(26): 261802, 2023 Jun 30.
Article in English | MEDLINE | ID: mdl-37450824

ABSTRACT

We present a search for the lepton flavor violating decays B^{+}→K^{+}τ^{±}ℓ^{∓}, with ℓ=(e,µ), using the full data sample of 772×10^{6} BB[over ¯] pairs recorded by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. We find no evidence for B^{±}→K^{±}τℓ decays and set upper limits on their branching fractions at the 90% confidence level in the (1-3)×10^{-5} range. The obtained limits are the world's best results.

SELECTION OF CITATIONS
SEARCH DETAIL
...