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Measurement of structure dependent radiative K+ → e+νγ decays using stopped positive kaons

Authors :
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
Source :
Physics Letters B, Vol 826, Iss, Pp 136913-(2022), Physics Letters
Publication Year :
2022
Publisher :
Elsevier, 2022.

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.

Details

Language :
English
ISSN :
03702693
Volume :
826
Database :
OpenAIRE
Journal :
Physics Letters B
Accession number :
edsair.doi.dedup.....64b28d6643f464054b23163dcb5034c6