Conference Presentation

PUBDB-2025-03748

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Measurements of semileptonic and leptonic B decays at Belle II

Martinov, T.Extern*DESY* ; Belle II Collaboration (Collaboration author)DESY*

2025

Abstract: Introduction● New Belle II leptonic and semileptonic results using the full Run 1 dataset of365 fb -1 or 390M BB̅ pairs collected at an e+ e- centre-of-mass energy at theY(4S) resonance mass (10.58 GeV)● One new leptonic B decay result○ Measurement of the B + → τ ν branching fraction with a hadronic tagging method■ See Giovanni Gaudino’s YSF talk this evening for more details● Two new semileptonic B decay results○ Determination of |V cb| using B → D l ν decays with an inclusive tagging method○ Test of lepton flavour universality with measurements of R(D + ) and R(D∗+ ) usingsemileptonic B tagging■ First result using semileptonic B tagging !■ First combined R(D) and R(D*) Belle II measurement

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Contributing Institute(s):

1. BELLE II Experiment (BELLE)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)

Experiment(s):

1. KEK: BELLE I/II

Appears in the scientific report 2025

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