introduction-weak-interaction-volume-one

after which time the nuclei had become depolarized, and a heat-exchange
gas was allowed to enter the sample chamber . The first few runs of th e
experiment were sufficient to demonstrate a definite asymmetry in th e
spatial distribution of decay electrons, and to indicate that A wa s
negative, implying that beta particles were preferentially emitted i n
the direction opposite to that of the nuclear spin . Further experiment s
were performed to demonstrate that the anisotropy was not, for example ,
due to distortions in the magnetic field of cerium magnesium nitrat el.
The variation in observed results for electron velocities betwee n
0 .4 and 0 .8 was measured, and was found to agree with the formula (3 .7 .4) .
Since the 60Co decay (3 .7 .3) is a pure Gamow-Teller transition, we writ e
A = -2 (Re(C~ CA) )I(IGA I 2 + ICAI2)
implying
A
'--1 ,
(3 .7 .5 )
Cl (3 .7 .6)
We note that, since the ratio is evidently not pure imaginary, th CAICA
e
experiment of Wu et al . established not only parity nonconservation, bu t
also charge conjugation noninvariance .
Having considered parity noninvariance in a pure Gamow-Teller transition ,
we now examine its effect on the neutron decay, which is a mixed r
transition . Since this is an - 'g -+ 4- process, we write I
r
MGT I f5",
M = 1 . We now define a number of parameters, and simplify them o n
the assumption that the interaction occuring in neutron decay has th e
form V,A : (53 )
I GVI 2 + 3 IGA I 2 , (3 .7 .7a )
al = I GV I 2
IGAI2
, (3 .7 .7b )
AY = -2 ( GA I 2 + Re(GV GA ) ) (3 .7 .7c )
BY
2
2 (IGA I
r Re(GV GA'')) , (3 .7 .7d )
D5 _ 2 Im (GV
(3 .7 .7e )
1 . Formula : 2 Ce(NO 3 ) 3 . 3 Hg(NO3 ) 2 24 H2O