Measurement of K^-_e3 branching ratio

2007/04/16 by V. I. Romanovsky, Romanovsky, V. I., S.A. Akimenko +46
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex

paper · pdf · doi:10.48550/arxiv.0704.2052

10 pages, 8 figures

openalex publication_date 2007/04/16 · arxiv created 2007/05/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The branching fraction for the decay K^- → π⁰ e ν is measured using in-flight decays detected with \bf ISTRA+ setup working at the 25 GeV negative secondary beam of the U-70 PS:\linebreak Br_K_e3= (5.124 ± 0.009 (stat) ± 0.029(norm) ± 0.030(syst))%. From this value the |V_us| element of the CKM matrix is extracted, using previously measured f₊(t) form factor: |V_us|=0.227 ± 0.002. The results are in agreement with recent measurements by BNL E865, FNAL KTeV, KLOE.

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