A
bstract
We present measurements of absolute branching fractions of hadronic and lep-tonic
$ D_s^{+} $
decays to
K
−
K
+
π
+
,
$ {{\overline{K}}^0} $
K
+
,
ηπ
+
,
μ
+
ν
μ
and
τ
+
ν
τ
and report a ...search for the leptonic
$ D_s^{+} $
→
e
+
ν
e
decays. The results are obtained from a data sample of 913 fb
−1
collected at or near the
$ \varUpsilon $
(4
S
) and
$ \varUpsilon $
(5
S
) resonances with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider. The branching fractions of hadronic decays are measured to be
$ \begin{array}{*{20}{c}} {\mathcal{B}\left( {D_s^{+}\ \to\ {K^{-}}{K^{+}}{\pi^{+}}} \right) = \left( {5.06\pm 0.15\pm 0.21} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\ \to\ {{\overline{K}}^0}{K^{+}}} \right) = \left( {2.95\pm 0.11\pm 0.09} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\ \to\ \eta {\pi^{+}}} \right) = \left( {1.82\pm 0.14\pm 0.07} \right)\%,} \\ \end{array} $
where the first and second uncertainties are statistical and systematic, respectively. The branching fractions of leptonic decays are measured to be
$ \begin{array}{*{20}{c}} {\mathcal{B}\left( {D_s^{+}\ \to\ {\mu^{+}}{\nu_{\mu }}} \right)=\left( {0.531\pm 0.028\pm 0.020} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\to {\tau^{+}}{\nu_{\tau }}} \right)=\left( {5.70\pm 0.21_{-0.30}^{-0.31 }} \right)\%,} \\ \end{array} $
which are combined to determine the
$ D_s^{+} $
meson decay constant
$ {f_{{{D_s}}}=\left( {255.5\pm 4.2\pm 5.1} \right)\ \mathrm{MeV}. $
We find no significant signal for
$ D_s^{+} $
→
e
+
ν
e
decays and set an upper limit of
$ \mathcal{B}\left( {D_s^{+}\ \to\ {e^{+}}{\nu_e}} \right) $
<
1
.
0(0
.
83)
×
10
−4
at 95% (90%) confidence level.
Study of τ−→KSπ−ντ decay at Belle Epifanov, D.; Aihara, H.; Aulchenko, V. ...
Physics letters. B,
10/2007, Letnik:
654, Številka:
3-4
Journal Article
Recenzirano
We present a study of the decay τ−→KSπ−ντ using a 351 fb−1 data sample collected with the Belle detector. The analysis is based on 53,110 lepton-tagged signal events. The measured branching fraction ...B(τ−→KSπ−ντ)=(0.404±0.002(stat.)±0.013(syst.))% is consistent with the world average value and has better accuracy. An analysis of the KSπ− invariant mass spectrum reveals contributions from the K∗(892)− as well as other states. For the first time the K∗(892)− mass and width have been measured in τ decay: M(K∗(892)−)=(895.47±0.20(stat.)±0.44(syst.)±0.59(mod.)) MeV/c2, Γ(K∗(892)−)=(46.2±0.6(stat.)±1.0(syst.)±0.7(mod.)) MeV. The K∗(892)− mass is significantly different from the current world average value.
A
bstract
We present the first model-independent measurement of the CKM unitarity triangle angle
ϕ
3
using
B
±
→ D
(
K
S
0
π
+
π
−
π
0
)
K
±
decays, where
D
indicates either a
D
0
or
D
¯
0
meson. ...Measurements of the strong-phase difference of the
D →
K
S
0
π
+
π
−
π
0
amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772
×
10
6
B
B
¯
events collected at the Υ(4
S
) resonance. We obtain
ϕ
3
= (
5.7
−
8.8
+
10.2
±
3
.
5
±
5
.
7)
°
and the suppressed amplitude ratio
r
B
= 0
.
323
±
0
.
147
±
0
.
023
±
0
.
051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on
ϕ
3
is (
−
29
.
7
,
109
.
5)
°
, which is consistent with the current world average.
A
bstract
We report a search for
B
decays to selected final states with the
η
c
meson:
B
±
→
K
±
η
c
π
+
π
−
,
B
±
→
K
±
η
c
ω
,
B
±
→
K
±
η
c
η
and
B
±
→
K
±
η
c
π
0
. The analysis is based on 772 × ...10
6
B
B
¯
pairs collected at the Υ(4
S
) resonance with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider. We set 90% confidence level upper limits on the branching fractions of the studied
B
decay modes, independent of intermediate resonances, in the range (0
.
6–5
.
3) × 10
−4
. We also search for molecular-state candidates in the
D
0
D
¯
∗
0
−
D
¯
0
D
∗
0
,
D
0
D
¯
0
+
D
¯
0
D
0
and
D
∗
0
D
¯
∗
0
+
D
¯
∗
0
D
∗
0
combinations, neutral partners of the
Z
(3900)
±
and
Z
(4020)
±
, and a poorly understood state
X
(3915) as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range (0
.
6–6
.
9) × 10
−5
.
We report evidence for the charged charmed-strange baryon \(\Xi _{c}(2930)^+\) with a signal significance of 3.9 \(\sigma \) with systematic errors included. The charged \(\Xi _{c}(2930)^+\) is found ...in its decay to \(K_{S}^{0} \Lambda _{c}^+\) in the substructure of \(\bar{B}^{0} \rightarrow K^{0}_{S} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}\) decays. The measured mass and width are \(2942.3 \pm 4.4 ({\mathrm{stat.}}) \pm {1.5}({\mathrm{syst.}})\) MeV/ \(c^{2}\) and \(14.8 \pm 8.8({\mathrm{stat.}}) \pm {2.5}({\mathrm{syst.}})\) MeV, respectively, and the product branching fraction is \(\mathcal{B}(\bar{B}^{0} \rightarrow \Xi _c(2930)^{+} \bar{\Lambda }_{c}^{-}) \mathcal{B}(\Xi _c(2930)^{+}\rightarrow \bar{K}^{0} \Lambda _{c}^{+})=2.37 \pm 0.51 ({\mathrm{stat.}})\pm 0.31({\mathrm{syst.}})\times 10^{-4}\) . We also measure \(\mathcal{B}(\bar{B}^{0} \rightarrow \bar{K}^{0} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}) = 3.99 \pm 0.76({\mathrm{stat.}}) \pm 0.51({\mathrm{syst.}}) \times 10^{-4}\) with greater precision than previous experiments, and present the results of a search for the charmonium-like state Y(4660) and its spin partner, \(Y_{\eta }\) , in the \(\Lambda _{c}^{+}\bar{\Lambda }_{c}^{-}\) invariant mass spectrum. No clear signals of the Y(4660) or \(Y_{\eta }\) 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 \((772\pm 11)\times 10^{6} B\bar{B}\) pairs collected at the \(\Upsilon (4S)\) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
We study bottomonium production in association with an \(\eta \) meson in \(e^+e^-\) annihilations near the \(\varUpsilon (5S)\) , at a centre-of-mass energy of \(\sqrt{s}=10.866\) GeV. The results ...are based on the 121.4 fb \(^{-1}\) data sample collected by the Belle experiment at the asymmetric-energy KEKB collider. Only the \(\eta \) meson is reconstructed and the missing-mass spectrum of \(\eta \) candidates is investigated. We observe the \(e^+e^-\rightarrow \eta \varUpsilon _J(1D)\) process and find evidence for the \(e^+e^-\rightarrow \eta \varUpsilon (2S)\) process, while no significant signals of \(\varUpsilon (1S)\) , \(h_b(1P)\) , nor \(h_b(2P)\) are found. Cross sections for the studied processes are reported.
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