A
bstract
We report a measurement of the electric dipole moment of the
τ
lepton (
dτ
) using an 833 fb
−
1
data sample collected near the Υ(4
S
) resonance, with the Belle detector at the KEKB ...asymmetric-energy
e
+
e
−
collider. Using an optimal observable method, we obtain the real and imaginary parts of
d
τ
as Re(
d
τ
) = (
−
0
.
62
±
0
.
63)
×
10
−
17
e
cm and Im(
d
τ
) = (
−
0
.
40
±
0
.
32)
×
10
−
17
e
cm, respectively. These results are consistent with null electric dipole moment at the present level of experimental sensitivity and improve the sensitivity by about a factor of three.
A
bstract
The first dedicated search for the
η
c
2
(1
D
) is carried out using the decays
B
+
→ η
c
2
(1
D
)
K
+
,
B
0
→
η
c
2
(1
D
)
K
S
0
,
B
0
→ η
c
2
(1
D
)
π
−
K
+
, and
B
+
→ η
c
2
(1
D
)
π
+
K
...S
0
with
η
c
2
(1
D
)
→ h
c
γ
. No significant signal is found. For the
η
c
2
(1
D
) mass range between 3795 and 3845 MeV
/c
2
, the branching-fraction upper limits are determined to be ℬ(
B
+
→ η
c
2
(1
D
)
K
+
)
×
ℬ(
η
c
2
(1
D
)
→ h
c
γ
)
<
3
.
7
×
10
−
5
, ℬ(
B
0
→ η
c
2
(1
D
)
K
0
)
×
ℬ(
η
c
2
(1
D
)
→ h
c
γ
)
<
3
.
5
×
10
−
5
, ℬ(
B
0
→ η
c
2
(1
D
)
π
−
K
+
)
×
ℬ(
η
c
2
(1
D
)
→ h
c
γ
)
<
1
.
0
×
10
−
4
, and ℬ(
B
+
→ η
c
2
(1
D
)
π
+
K
S
0
)
×
ℬ(
η
c
2
(1
D
)
→ h
c
γ
)
<
1
.
1
×
10
−
4
at 90% C.L. The analysis is based on the 711 fb
−
1
data sample collected on the ϒ(4
S
) resonance by the Belle detector, which operated at the KEKB asymmetric-energy
e
+
e
−
collider.
We study bottomonium production in association with an Formula omitted meson in Formula omitted annihilations near the Formula omitted, at a centre-of-mass energy of Formula omitted GeV. The results ...are based on the 121.4 fb Formula omitted data sample collected by the Belle experiment at the asymmetric-energy KEKB collider. Only the Formula omitted meson is reconstructed and the missing-mass spectrum of Formula omitted candidates is investigated. We observe the Formula omitted process and find evidence for the Formula omitted process, while no significant signals of Formula omitted, Formula omitted, nor Formula omitted are found. Cross sections for the studied processes are reported.
We report the first observation of the Ξc(2930)0 charmed-strange baryon with a significance greater than 5σ. The Ξc(2930)0 is found in its decay to K-Λc+ in B-→K-Λc+Λ¯c- decays. The measured mass and ...width are 2928.9±3.0(stat.)-12.0+0.9(syst.) MeV/c2 and 19.5±8.4(stat.)-7.9+5.9(syst.) MeV, respectively, and the product branching fraction is B(B-→Ξc(2930)0Λ¯c-)B(Ξc(2930)0→K-Λc+)=1.73±0.45(stat.)±0.21(syst.)×10-4. We also measure B(B-→K-Λc+Λ¯c-)=4.80±0.43(stat.)±0.60(syst.)×10-4 with improved precision, and search for the charmonium-like state Y(4660) and its spin partner, Yη, in the Λc+Λ¯c- invariant mass spectrum. No clear signals of the Y(4660) nor its spin partner are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of (772±11)×106BB¯ pairs collected at the Υ(4S) resonance by the Belle detector at the KEKB asymmetric energy electron–positron collider.
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