Physics Letters B (Mar 2022)
Measurement of structure dependent radiative K+ → e+νγ decays using stopped positive kaons
- H. Ito,
- A. Kobayashi,
- S. Bianchin,
- T. Cao,
- C. Djalali,
- D.H. Dongwi,
- T. Gautam,
- D. Gill,
- M.D. Hasinoff,
- K. Horie,
- Y. Igarashi,
- J. Imazato,
- N. Kalantarians,
- H. Kawai,
- S. Kimura,
- S. Kodama,
- M. Kohl,
- H. Lu,
- O. Mineev,
- P. Monaghan,
- S. Shimizu,
- S. Strauch,
- M. Tabata,
- R. Tanuma,
- A. Toyoda,
- H. Yamazaki,
- N. Yershov
Affiliations
- H. Ito
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- A. Kobayashi
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- S. Bianchin
- TRIUMF, Vancouver, BC, V6T 2A3, Canada
- T. Cao
- Physics Department, Hampton University, VA 23668, USA
- C. Djalali
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
- D.H. Dongwi
- Physics Department, Hampton University, VA 23668, USA
- T. Gautam
- Physics Department, Hampton University, VA 23668, USA
- D. Gill
- TRIUMF, Vancouver, BC, V6T 2A3, Canada
- M.D. Hasinoff
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
- K. Horie
- Department of Physics, Osaka University, Osaka, 560-0043, Japan
- Y. Igarashi
- High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
- J. Imazato
- High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
- N. Kalantarians
- Physics Department, Hampton University, VA 23668, USA
- H. Kawai
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- S. Kimura
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- S. Kodama
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- M. Kohl
- Physics Department, Hampton University, VA 23668, USA
- H. Lu
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
- O. Mineev
- Institute for Nuclear Research, Moscow, 117312, Russia
- P. Monaghan
- Physics Department, Hampton University, VA 23668, USA
- S. Shimizu
- Department of Physics, Osaka University, Osaka, 560-0043, Japan; Corresponding author.
- S. Strauch
- Department of Physics, University of South Carolina, USA
- M. Tabata
- Department of Physics, Chiba University, Chiba, 263-8522, Japan
- R. Tanuma
- Department of Physics, Rikkyo University, Toshima, 171-8501, Japan
- A. Toyoda
- High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
- H. Yamazaki
- High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
- N. Yershov
- Institute for Nuclear Research, Moscow, 117312, Russia
- Journal volume & issue
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Vol. 826
p. 136913
Abstract
The structure dependent radiative K+→e+νγ (Ke2γSD+) decay was investigated with stopped positive kaons. The e+ momentum spectra containing 574±30 Ke2γSD+ events with a K+→μ+ν (Kμ2) background of 28±19 events were measured with and without a photon in coincidence and analyzed with Monte Carlo simulations for acceptance and detector response to extract the ratio of the branching ratio of the Ke2γSD+ decay and the K+→e+ν decay including the internal bremsstrahlung process (Ke2(γ)). A value of Br(Ke2γSD+)/Br(Ke2(γ))=1.12±0.07stat±0.04syst was obtained. This indicates a partial branching ratio, Br(Ke2γSD+,pe>200MeV/c,Eγ>10MeV)/Br(Kμ2)=(1.85±0.11stat±0.07syst)×10−5, which is 25% (∼2.5σ) higher than the previous experimental result.
