We report measurements of the branching fractions and CP asymmetries for B(±)→ηh(±) (h=K or π) and the observation of the decay B(0)→ηK(0) from the final data sample of 772×10(6) B ̅B pairs collected ...with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured branching fractions are B(B(±)→ηK(±))=(2.12±0.23±0.11)×10(-6), B(B(±)→ηπ(±))=(4.07±0.26±0.21)×10(-6), and B(B(0)→ηK(0))=(1.27(-0.29)(+0.33)±0.08)×10(-6), where the last decay is observed for the first time with a significance of 5.4 standard deviations (σ). We also find evidence for CP violation in the charged B modes, A(CP)(B(±)→ηK(±))=-0.38±0.11±0.01 and A(CP)(B(±)→ηπ(±))=-0.19±0.06±0.01 with significances of 3.8 σ and 3.0 σ, respectively. For all measurements, the first and second uncertainties are statistical and systematic, respectively.
The NA48 experiment at CERN has performed a new measurement of direct CP violation, based on data taken in 1997 by simultaneously collecting
K
L
and
K
S
decays into
π
0
π
0 and
π
+
π
−. The result ...for the CP violating parameter
Re
(ε
′/ε)
is (18.5±4.5(stat)±5.8(syst))×10
−4.
We investigate the decays
D
0
→
π
−
ℓ
+
ν
and
D
0
→
K
−
ℓ
+
ν
, where
ℓ is
e or
μ, using approximately 7 fb
−1 of data collected with the CLEO III detector. We find
R
0
=
B
(
D
0
→
π
−
e
+
ν
)
/
B
(
...D
0
→
K
−
e
+
ν
)
=
0.082
±
0.006
±
0.005
. Fits of the kinematic distributions provide parameters describing their form factors. Combining the form factor results with
R
0
gives
|
f
+
π
(
0
)
|
2
|
V
c
d
|
2
/
|
f
+
K
(
0
)
|
2
|
V
c
s
|
2
=
0.038
−
0.007
−
0.003
+
0.006
+
0.005
.
The general properties needed in targets (sources) for high precision, high accuracy measurements are reviewed. The application of these principles to the problem of developing targets for the ...Fission TPC is described. Longer term issues, such as the availability of actinide materials, improved knowledge of energy losses and straggling and the stability of targets during irradiation are also discussed.
A
bstract
We search for
CP
violation in the decay
${D^{+}}\to K_S^0{K^{+}}$
using a data sample with an integrated luminosity of 977 fb
−1
collected with the Belle detector at the KEKB
e
+
e
−
...asymmetric-energy collider. No
CP
violation has been observed and the
CP
asymmetry in
${D^{+}}\to K_S^0{K^{+}}$
decay is measured to be (−0.25 ± 0.28 ± 0.14)%, which is the most sensitive measurement to date. After subtracting
CP
violation due to
${K^0}-{{\overline{K}}^0}$
mixing, the
CP
asymmetry in
${D^{+}}\to {{\overline{K}}^0}{K^{+}}$
decay is found to be (+0.08 ± 0.28 ± 0.14)%.
We search for lepton-flavor-violating and lepton-number-violating τ decays into a lepton (ℓ = electron or muon) and two charged mesons (h, h' = π± or K±) using 854 fb-1 of data collected with the ...Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain 90% confidence level upper limits on the τ → ℓhh' branching fractions in the range (2.0-8.4)×10-8. These results improve upon our previously published upper limits by factors of about 1.8 on average.
A fission TPC is being developed to measure the energy-dependent neutron induced fission cross sections of the major and minor actinides to an accuracy of better than 1%. Achieving such an accuracy ...will depend in part, on the ability of the TPC to provide precise tracking and identification of charged particles. A measurement of the α-decay to spontaneous fission branching ratio of 252Cf used to benchmark the performance of the TPC will be discussed.
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