Precise measurement of the pi+-->pi0 e+nu branching ratio.
Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare pi(+)-->pi(0)e(+)nu (pi(beta)) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed pi(beta) decays to the number of observed pi(+)-->e(+)nu (pi(e2)) decays. We find the value of Gamma(pi(+)-->pi(0)e(+)nu)/Gamma(total)=[1.036+/-0.004(stat)+/-0.004(syst)+/-0.003(pi(e2))]x10(-8), where the first uncertainty is statistical, the second systematic, and the third is the pi(e2) branching ratio uncertainty. Our result agrees well with the standard model prediction.
Pocanić
D
D
Department of Physics, University of Virginia, Charlottesville, VA 22904-4714, USA. pocanic@virginia.edu
Frlez
E
E
Baranov
V A
VA
Bertl
W
W
Brönnimann
Ch
Ch
Bychkov
M
M
Crawford
J F
JF
Daum
M
M
Khomutov
N V
NV
Korenchenko
A S
AS
Korenchenko
S M
SM
Kozlowski
T
T
Kravchuk
N P
NP
Kuchinsky
N A
NA
Li
W
W
Minehart
R C
RC
Mzhavia
D
D
Ritchie
B G
BG
Ritt
S
S
Rozhdestvensky
A M
AM
Sidorkin
V V
VV
Smith
L C
LC
Supek
I
I
Tsamalaidze
Z
Z
VanDevender
B A
BA
Wang
Y
Y
Wirtz
H-P
HP
Ziock
K O H
KO