9 Symmetry Violations and Quark Flavour Physics
563
1. Event numbers of up to 298 million events in the K e3 mode and 15 million events
in the K μ3 mode.
2. An apparatus design such that the decay products (π and electron) traverse only
minute amounts of matter (about 0.3–0.4 g cm −2 ), thus diminishing corrections
due to secondary interactions of these particles.
3. The precision of the K μ3 asymmetry measurements is a factor of 4 below the
value for K e3 , making a comparison between the two possible. Table 9.3 gives
the results; the average δ L = (3.316 ± 0.053) × 10 −3 .
The charge asymmetries for K e3 and K μ3 decays are equal to within 8%: δ
e
L /δ
μ
L =
1.04 ± 0.08. Assuming the validity of the = rule, which is supported by
the present experiments, we obtain e ε = (1.658 ± 0.026) × 10 −3 . If we use the
most precise tests of the = rule by the CPLEAR experiment [185], there is
a small correction
1 − |x| 2
|1 − x| 2 = 0.996 ± 0.012 .
(9.152)
9.5.5.7 Parameters of CP Violation in the K 0 System: m(ε /ε)
K S Lifetime We take the average of the older measurements combined with the two
most recent measurements by the kTeV collaboration, (0.8965 ± 0.0007) × 10 −10
s [180], and by the NA48 collaboration, (0.89598 ± 0.0007) × 10 −10 s [197]. Our
grand average is
τ S = (0.8959 ± 0.0004) × 10
−10 s .
(9.153)
Table 9.3 Charge asymmetry measurements in K l3 decays
Group and reference
Year Decay mode Result [×10 3 ]
δ [×10 3 ]
Columbia [164, 192]
1969 K e3
2.46 ± 0.59
Columbia–Harvard–CERN
[193]
1970 K e3
3.46 ± 0.33
K e3 average
San Diego–Berkeley [194]
1972 K e3
3.6 ± 1.8
3.322 ± 0.055
Princeton [186]
1973 K e3
3.18 ± 0.38
CERN–Heidelberg [187]
1974 K e3
3.41 ± 0.18
kTeV [188]
2002 K e3
3.322 ± 0.058 ± 0.047
NA48 [157]
2003 K e3
3.317 ± 0.070 ± 0.072
Brookhaven–Yale [190]
1973 K e3 + K μ3
3.33 ± 0.50
SLAC–Berkeley [165, 195]
1969 K μ3
5.8 ± 1.7
Berkeley [196]
1972 K μ3
6.0 ± 1.4
K μ3 average
Stanford [189]
1972 K μ3
2.78 ± 0.51
3.19 ± 0.24
CERN–Heidelberg [187]
1974 K μ3
3.13 ± 0.29
The K μ3 and K e3 average value is δ L = (3.316 ± 0.053) × 10 −3
563
1. Event numbers of up to 298 million events in the K e3 mode and 15 million events
in the K μ3 mode.
2. An apparatus design such that the decay products (π and electron) traverse only
minute amounts of matter (about 0.3–0.4 g cm −2 ), thus diminishing corrections
due to secondary interactions of these particles.
3. The precision of the K μ3 asymmetry measurements is a factor of 4 below the
value for K e3 , making a comparison between the two possible. Table 9.3 gives
the results; the average δ L = (3.316 ± 0.053) × 10 −3 .
The charge asymmetries for K e3 and K μ3 decays are equal to within 8%: δ
e
L /δ
μ
L =
1.04 ± 0.08. Assuming the validity of the = rule, which is supported by
the present experiments, we obtain e ε = (1.658 ± 0.026) × 10 −3 . If we use the
most precise tests of the = rule by the CPLEAR experiment [185], there is
a small correction
1 − |x| 2
|1 − x| 2 = 0.996 ± 0.012 .
(9.152)
9.5.5.7 Parameters of CP Violation in the K 0 System: m(ε /ε)
K S Lifetime We take the average of the older measurements combined with the two
most recent measurements by the kTeV collaboration, (0.8965 ± 0.0007) × 10 −10
s [180], and by the NA48 collaboration, (0.89598 ± 0.0007) × 10 −10 s [197]. Our
grand average is
τ S = (0.8959 ± 0.0004) × 10
−10 s .
(9.153)
Table 9.3 Charge asymmetry measurements in K l3 decays
Group and reference
Year Decay mode Result [×10 3 ]
δ [×10 3 ]
Columbia [164, 192]
1969 K e3
2.46 ± 0.59
Columbia–Harvard–CERN
[193]
1970 K e3
3.46 ± 0.33
K e3 average
San Diego–Berkeley [194]
1972 K e3
3.6 ± 1.8
3.322 ± 0.055
Princeton [186]
1973 K e3
3.18 ± 0.38
CERN–Heidelberg [187]
1974 K e3
3.41 ± 0.18
kTeV [188]
2002 K e3
3.322 ± 0.058 ± 0.047
NA48 [157]
2003 K e3
3.317 ± 0.070 ± 0.072
Brookhaven–Yale [190]
1973 K e3 + K μ3
3.33 ± 0.50
SLAC–Berkeley [165, 195]
1969 K μ3
5.8 ± 1.7
Berkeley [196]
1972 K μ3
6.0 ± 1.4
K μ3 average
Stanford [189]
1972 K μ3
2.78 ± 0.51
3.19 ± 0.24
CERN–Heidelberg [187]
1974 K μ3
3.13 ± 0.29
The K μ3 and K e3 average value is δ L = (3.316 ± 0.053) × 10 −3