We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients A{sub 9}/A{sub 7} and A{sub 10}/A{sub 7} in B{yields}K{sup *}l{sup +}l{sup -}, where l ...represents an electron or a muon. We find evidence for the forward-backward asymmetry with a significance of 3.4{sigma}. The results are obtained from a data sample containing 386x10{sup 6} BB pairs that were collected on the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider.
We present a search for the decays B+→μ+νμ and B+→e+νe in a 253 fb−1 data sample collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy B factory. We find no ...significant evidence for a signal and set 90% confidence level upper limits of B(B+→μ+νμ)<1.7×10−6 and B(B+→e+νe)<9.8×10−7.
The angular distributions of the baryon–antibaryon low-mass enhancements seen in the charmless three-body baryonic
B decays
B
+
→
p
p
¯
K
+
,
B
0
→
p
p
¯
K
S
0
and
B
0
→
p
Λ
¯
π
−
are reported. A ...quark fragmentation interpretation is supported, while the gluonic resonance picture is disfavored. Searches for the
Θ
+
and
Θ
+
+
pentaquarks in the relevant decay modes and possible glueball states
G
with
2.2
GeV
/
c
2
<
M
p
p
¯
<
2.4
GeV
/
c
2
in the
p
p
¯
systems give null results. We set upper limits on the products of branching fractions,
B
(
B
0
→
Θ
+
p
¯
)
B
(
Θ
+
→
p
K
S
0
)
<
2.3
×
10
−7
,
B
(
B
+
→
Θ
+
+
p
¯
)
B
(
Θ
+
+
→
p
K
+
)
<
9.1
×
10
−8
, and
B
(
B
+
→
G
K
+
)
B
(
G
→
p
p
¯
)
<
4.1
×
10
−7
at the 90% confidence level. The analysis is based on a 140 fb
−1 data sample recorded on the
ϒ
(
4
S
)
resonance with the Belle detector at the KEKB asymmetric energy
e
+
e
−
collider.
We report measurements of the branching fraction and CP violation parameters in B(0)-->D+ D- decays. The results are based on a data sample that contains 535 x 10(6) BB pairs collected at the ...Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain 1.97+/-0.20(stat) +/- 0.20(syst) x 10(-4) for the branching fraction of B0-->D+D-. The measured values of the CP violation parameters are S=-1.13+/-0.37+/-0.09, A=0.91+/-0.23+/-0.06, where the first error is statistical and the second is systematic. We find evidence of CP violation in B0-->D+D- at the 4.1sigma confidence level. While the value of S is consistent with expectations from other measurements, the value of the parameter A favors large direct CP violation at the 3.2sigma confidence level, in contradiction to standard model expectations.
We report results of a search for the invisible decay of the Upsilon(1S) via the Upsilon(3S)-->pi+ pi- Upsilon(1S) transition using a data sample of 2.9 fb-1 at the Upsilon(3S) resonance. The data ...were collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. No signal is found, and an upper limit for the branching fraction at the 90% confidence level is determined to be B(Upsilon(1S)-->invisible)<2.5 x 10(-3).
Observation of B decays to two kaons Abe, K; Aihara, H; Anipko, D ...
Physical review letters,
05/2007, Letnik:
98, Številka:
18
Journal Article
Recenzirano
Using 449x10(6) BBover pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider, we observe clear signals for B(+)-->Kover (0)K(+) and B(0)-->Kover (0)K(0) decays with ...5.3sigma and 6.0sigma significance, respectively. We measure the branching fractions B(B(+)-->Kover (0)K(+))=(1.22(-0.28-0.16)(+0.32+0.13))x10(-6) and B(B(0)-->Kover (0)K(0))=(0.87(-0.20)(+0.25)+/-0.09)x10(-6), and partial-rate asymmetries A(CP)(B(+)-->Kover (0)K(+))=0.13(-0.24)(+0.23)+/-0.02 and A(CP)(B(0)-->Kover (0)K(0))=-0.58(-0.66)(+0.73)+/-0.04. From a simultaneous fit, we also obtain B(B(+)-->K(0)pi(+))=(22.8(-0.7)(+0.8)+/-1.3)x10(-6) and A(CP)(B(+)-->K(0)pi(+))=0.03+/-0.03+/-0.01. The first and second error in the branching fractions and the partial-rate asymmetries are statistical and systematic, respectively. No signal is observed for B(0)-->K(+)K(-) decays, and for this branching fraction, we set an upper limit of 4.1x10(-7) at the 90% confidence level.
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