576
K. Kleinknecht and U. Uwer
Fig. 9.21 Time sequence of
published measurements of
the parameter e(ε /ε) of
direct CP violation. The
experiments at CERN are
marked by filled circles and
the experiments at Fermilab
are marked by open squares.
The kTeV result from 2003 is
a reanalysis of the data from
the kTeV 1999 result (see
[204] and also
[180, 200–203])
9.5.6.6 Conclusions About Direct CP Violation, e(ε /ε) and the
Wu–Yang Triangle
The two experiments kTeV and NA48 have definitively confirmed the original
observation of the NA31 team that direct CP violation exists. The results of all
published experiments on // are shown in Fig. 9.21. Therefore, CP violation as
observed in the K meson system is a part of the weak interaction due to weak quark
mixing. Exotic, new interactions such as the superweak interaction are not needed.
We therefore have a very precise experimental result for ε /ε. The theoretical
calculations of ε /ε within the Standard Model, however, are still not very precise.
This does not change the main conclusion of the experiments that ε is different
from zero and positive, i.e. direct CP violation exists.
If we take into account the four relevant experiments NA31, E731, NA48, and
kTeV, the weighted average comes out to be
ε
ε
= (16.7 ± 1.6) × 10
−4 .
(9.175)
The consistency of the result is not completely satisfactory, since χ 2 /ndf = 6.3/3.
If the phase of ε as defined in (9.92), arg ε = (42.3 ± 1.5) ◦ [149], is inferred, then
a more precise value for the component of ε transverse to ε can be derived.
We have done a complete fit to the Wu–Yang triangle (9.90), using as input
ε
ε
= (16.7 ± 1.6) × 10
−4 , e ε = (1.658 ± 0.0265) × 10
−3 ,
Φ +− = 43.3
◦
± 0.4
◦ , Φ 00 − Φ +− = (0.36 ± 0.43)
◦ ,
|η +− | = (2.230 ± 0.006) × 10
−3 , |η 00 | = (2.225 ± 0.007) × 10
−3 ,
arg ε = 43.4 ± 0.1
◦ , arg ε
= 42.3
◦
± 1.5
◦ .
K. Kleinknecht and U. Uwer
Fig. 9.21 Time sequence of
published measurements of
the parameter e(ε /ε) of
direct CP violation. The
experiments at CERN are
marked by filled circles and
the experiments at Fermilab
are marked by open squares.
The kTeV result from 2003 is
a reanalysis of the data from
the kTeV 1999 result (see
[204] and also
[180, 200–203])
9.5.6.6 Conclusions About Direct CP Violation, e(ε /ε) and the
Wu–Yang Triangle
The two experiments kTeV and NA48 have definitively confirmed the original
observation of the NA31 team that direct CP violation exists. The results of all
published experiments on // are shown in Fig. 9.21. Therefore, CP violation as
observed in the K meson system is a part of the weak interaction due to weak quark
mixing. Exotic, new interactions such as the superweak interaction are not needed.
We therefore have a very precise experimental result for ε /ε. The theoretical
calculations of ε /ε within the Standard Model, however, are still not very precise.
This does not change the main conclusion of the experiments that ε is different
from zero and positive, i.e. direct CP violation exists.
If we take into account the four relevant experiments NA31, E731, NA48, and
kTeV, the weighted average comes out to be
ε
ε
= (16.7 ± 1.6) × 10
−4 .
(9.175)
The consistency of the result is not completely satisfactory, since χ 2 /ndf = 6.3/3.
If the phase of ε as defined in (9.92), arg ε = (42.3 ± 1.5) ◦ [149], is inferred, then
a more precise value for the component of ε transverse to ε can be derived.
We have done a complete fit to the Wu–Yang triangle (9.90), using as input
ε
ε
= (16.7 ± 1.6) × 10
−4 , e ε = (1.658 ± 0.0265) × 10
−3 ,
Φ +− = 43.3
◦
± 0.4
◦ , Φ 00 − Φ +− = (0.36 ± 0.43)
◦ ,
|η +− | = (2.230 ± 0.006) × 10
−3 , |η 00 | = (2.225 ± 0.007) × 10
−3 ,
arg ε = 43.4 ± 0.1
◦ , arg ε
= 42.3
◦
± 1.5
◦ .