Measurement of the Michel parameter rho in muon decay.
The TWIST Collaboration has measured the Michel parameter rho in normal muon decay, mu(+)--> e(+)nu(e)nu (mu). In the standard model, rho = 3/4. Deviations from this value imply mixing of left- and right-handed muon and electron couplings. We find rho=0.750 80+/-0.000 32(stat) +/- 0.000 97(syst) +/- 0.000 23, where the last uncertainty represents the dependence of rho on the Michel parameter eta. This result sets new limits on the W(L)-W(R) mixing angle in left-right symmetric models.
Musser
J R
JR
Texas A&M University, College Station, Texas 77843, USA.
Bayes
R
R
Davydov
Yu I
YI
Depommier
P
P
Doornbos
J
J
Faszer
W
W
Gagliardi
C A
CA
Gaponenko
A
A
Gill
D R
DR
Green
P
P
Gumplinger
P
P
Hasinoff
M D
MD
Henderson
R S
RS
Hu
J
J
Jamieson
B
B
Kitching
P
P
Koetke
D D
DD
Krushinsky
A A
AA
Lachin
Yu Yu
YY
Macdonald
J A
JA
MacDonald
R P
RP
Marshall
G M
GM
Mathie
E L
EL
Miasoedov
L V
LV
Mischke
R E
RE
Nord
P M
PM
Olchanski
K
K
Olin
A
A
Openshaw
R
R
Porcelli
T A
TA
Poutissou
J-M
JM
Poutissou
R
R
Quraan
M A
MA
Rodning
N L
NL
Selivanov
V
V
Sheffer
G
G
Shin
B
B
Sobratee
F
F
Stanislaus
T D S
TD
Tacik
R
R
Torokhov
V D
VD
Tribble
R E
RE
Vasiliev
M A
MA
Wright
D H
DH