Here, we search for CP violation in the singly-Cabibbo-suppressed decay D0 → K+K–π+π– using data corresponding to an integrated luminosity of 988 fb–1 collected by the Belle detector at the KEKB e+e– ...collider. We measure a set of five kinematically dependent CP asymmetries, of which four asymmetries are measured for the first time. The set of asymmetry measurements can be sensitive to CP violation via interference between the different partial-wave contributions to the decay and performed on other pseudoscalar decays. We find no evidence of CP violation.
We study charmless hadronic decays of charged B mesons to the final states KS0KS0K± and KS0KS0π± using a 711 fb−1 data sample that contains 772×106 BB¯ pairs and was collected at the ϒ(4S) resonance ...with the Belle detector at the KEKB asymmetric-energy e+e− collider. For B±→KS0KS0K±, the measured branching fraction and direct CP asymmetry are 10.42±0.43(stat)±0.22(syst)×10−6 and +1.6±3.9(stat)±0.9(syst)%, respectively. In the absence of a statistically significant signal for B±→KS0KS0π±, we obtain a 90% confidence-level upper limit on its branching fraction as 8.7×10−7.
We report the first measurement of the T-odd moments in the decay D0→KS0π+π−π0 from a data sample corresponding to an integrated luminosity of 966 fb−1 collected by the Belle experiment at the KEKB ...asymmetric-energy e+e− collider. From these moments we determine the CP-violation-sensitive asymmetry aCPT-odd=−0.28±1.38(stat.)−0.76+0.23(syst.)×10−3, which is consistent with no CP violation. In addition, we perform aCPT−odd measurements in different regions of the D0→KS0π+π−π0 phase space; these are also consistent with no CP violation.
We present a measurement of the branching fraction and the longitudinal polarization fraction of B0->p+p- decays, as well as the time-dependent CP violating parameters in decays into longitudinally ...polarized p+p- pairs with Belle's final data set of 772x106 BB pairs, at the Y(4S) resonance, collected at the asymmetric-energy e+e- collider KEKB.
We report a new measurement of the exclusive e+e−→D(*)±D*∓ cross sections as a function of the center-of-mass energy from the D(*)±D*∓ threshold through s=6.0 GeV, using the initial-state radiation ...technique. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 951 fb−1. The accuracy of the cross section measurement is increased by a factor of 2 over the first Belle study. We perform the first angular analysis of the e+e−→D*±D*∓ process and decompose this exclusive cross section into three components corresponding to the D* helicities.
Using data collected in the Belle experiment at the KEKB asymmetric-energy e+e - collider we search for transitions ?(4S) ? ?b(1S)?, ?(5S) ? ?b(1S)? and ?(5S) ? ?b(2S)?. No significant signals are ...observed and we set 90% confidence level upper limits on the corresponding visible cross sections: 0.2 pb, 0.4 pb and 1.9 pb, respectively
Observation of ϒ(2S)→γη_{b}(1S) Decay Fulsom, B G; Pedlar, T K; Adachi, I ...
Physical review letters,
2018-Dec-07, 20181207, Letnik:
121, Številka:
23
Journal Article
Recenzirano
We report the observation of ϒ(2S)→γη_{b}(1S) decay based on an analysis of the inclusive photon spectrum of 24.7 fb^{-1} of e^{+}e^{-} collisions at the ϒ(2S) center-of-mass energy collected with ...the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure a branching fraction of Bϒ(2S)→γη_{b}(1S)=(6.1_{-0.7-0.6}^{+0.6+0.9})×10^{-4} and derive an η_{b}(1S) mass of 9394.8_{-3.1-2.7}^{+2.7+4.5} MeV/c^{2}, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.
The first dedicated search for the ηc2(1D) is carried out using the decays B+ → ηc2(1D)K+, B0 → ηc2(1D)K$0\atop{S}$, B0 → ηc2(1D)π-K+, and B+ → ηc2(1D)π +K$0\atop{S}$ with ηc2(1D) → hcγ. No ...significant signal is found. For the ηc2(1D) mass range between 3795 and 3845 MeV/c2, the branching-fraction upper limits are determined to be B(B+ → ηc2(1D)K+) × B(ηc2(1D) → hcγ) < 3.7 × 10-5 , B(B0 → ηc2(1D)K$0\atop{S}$) × B(ηc2(1D) → hcγ) < 3.5 × 10-5, B(B0 → ηc2(1D)π-K+) × B(ηc2(1D) → hcγ) < 1.0 × 10-4, and B(B+ → ηc2(1D)π+K$0\atop{S}$) × B(ηc2(1D) → hcγ) < 1.1 × 10-4 at 90% C. L. The analysis is based on the 711 fb-1 data sample collected on the Υ(4S) resonance by the Belle detector, which operated at the KEKB asymmetric-energy e+e- collider.
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
.
Abstract
We present a measurement of the Michel parameters of the $\tau$ lepton, $\bar{\eta}$ and $\xi\kappa$, in the radiative leptonic decay $\tau^- \rightarrow \ell^- \nu_{\tau} \bar{\nu}_{\ell} ...\gamma$ using 711 f$\mathrm{b}^{-1}$ of collision data collected with the Belle detector at the KEKB $e^+e^-$ collider. The Michel parameters are measured in an unbinned maximum likelihood fit to the kinematic distribution of $e^+e^-\rightarrow\tau^+\tau^-\rightarrow (\pi^+\pi^0 \bar{\nu}_\tau)(\ell^-\nu_{\tau}\bar{\nu}_{\ell}\gamma)$$(\ell=e$ or $\mu)$. The measured values of the Michel parameters are $\bar{\eta} = -1.3 \pm 1.5 \pm 0.8$ and $\xi\kappa = 0.5 \pm 0.4 \pm 0.2$, where the first error is statistical and the second is systematic. This is the first measurement of these parameters. These results are consistent with the Standard Model predictions within their uncertainties, and constrain the coupling constants of the generalized weak interaction.
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