Proton energy spectra in the nonmesonic weak decay of 12lambdaC and 28lambdaSi hypernuclei.
Numbers of protons per Gamma hypernuclear weak decay were measured as a function of proton energy above 40 MeV, explicitly identifying production of Gamma hypernuclei by the (pi+,K+) reaction. The ratios between the neutron-stimulated to proton-stimulated nonmesonic decay widths, Gamma((Lambda)n-->nn)/Gamma((Lambda)p-->np) ( = Gamma(n)/Gamma(p)) were extracted by fitting the proton energy spectra. The present result claims that the proton yields are suppressed and the Gamma(n)/Gamma(p) ratios are close to 1 both for 12LambdaC and 28LambdaSi in contradiction to theoretical expectations based on meson exchange models.
Hashimoto
O
O
Department of Physics, Tohoku University, Sendai 980-8578, Japan.
Ajimura
S
S
Aoki
K
K
Bhang
H
H
Hasegawa
T
T
Hotchi
H
H
Kim
Y D
YD
Kishimoto
T
T
Maeda
K
K
Noumi
H
H
Ohta
Y
Y
Omata
K
K
Outa
H
H
Park
H
H
Sato
Y
Y
Sekimoto
M
M
Shibata
T
T
Takahashi
T
T
Youn
M
M