We report preliminary results on the analysis of the three-body Y(10860)=> B barB pi, Y(10860) => (B barB* + c.c.) pi and Y(10860)=> B* barB* pi decays including an observation of the Y(10860)=> ...Zb(10610)+- pi-+ => B barB*+c.c+- pi-+ and Y(10860)=> Zb(10650)+- pi-+ => B* barB*+- pi-+ decays as intermediate channels. We measure branching fractions of the three-body decays to be Br(Y(10860)=> B barB*+c.c.+- pi-+)=(28.3+-2.9+-4.6)x10^{-3} and Br(Y(10860)=> B* barB*+- pi-+)=(14.1+-1.9+-2.4)x10^{-3} and set 90% C.L. upper limit Br(Y(10860)=> B barB+- pi-+)<4.0x10^{-3}. We also report results on the amplitude analysis of the three-body Y(10860)=>Y(nS)pi+pi-, n=1,2,3 decays and the analysis of the internal structure of the three-body Y(10860)=>hb(mP)pi+pi-, m=1,2 decays. The results are based on a 121.4 1/fb data sample collected with the Belle detector at a center-of-mass energy near the Y(10860).
We report results on the studies of the \(e^+e^-\to B_s^{(*)}\bar{B}_s^{(*)}\) processes. The results are based on a \(121.4\) fb\(^{-1}\) data sample collected with the Belle detector at the ...center-of-mass energy near the \(\Upsilon(10860)\) peak and \(16.4\) fb\(^{-1}\) of data collected at 19 energy points in the range from 10.77 to 11.02 GeV. We observe a clear \(e^+e^-\to\Upsilon(10860)\to B_s^{(*)}\bar{B}_s^{(*)}\) signal, with no statistically significant signal of \(e^+e^-\to \Upsilon(11020)\to B_s^{(*)}\bar{B}_s^{(*)}\). The relative production ratio of \(B_s^*\bar{B}_s^*\), \(B_s\bar{B}_s^{*}\), and \(B_s\bar{B}_s\) final states at \(\sqrt{s}=10.866\) GeV is measured to be \(7:\) \(0.856\pm0.106(stat.)\pm0.053(syst.):\) \(0.645\pm0.094(stat.)^{+0.030}_{-0.033}(syst.)\). An angular analysis of the \(B_s^*\bar{B}_s^*\) final state produced at the \(\Upsilon(10860)\) peak is also performed.
We report a measurement of the time-integrated \(CP\) asymmetry in the neutral charm meson decay \(D^0 \to K^0_S K^0_S\) using 921~fb\(^{-1}\) data collected at the \(\Upsilon(4S)\) and ...\(\Upsilon(5S)\) resonances with the Belle detector at the KEKB asymmetric-energy \(e^+e^-\) collider. The observed asymmetry is $$ A_{CP}(D^0 \to K^0_S K^0_S) = (-0.02 \pm 1.53 \pm 0.17) \%, $$ where the first uncertainty is statistical and the second systematic. This latter uncertainty is dominated by the error of the normalisation channel. The result is consistent with Standard Model expectations and improves the uncertainty with respect to previous measurement of this quantity by more than a factor of three.
We report a search for \(B^{0}\to \eta \eta \) with a data sample corresponding to an integrated luminosity of \(698 \,{\rm fb}^{-1}\) containing \(753 \times 10^{6}\) \(B\bar{B}\) pairs collected at ...the \(\Upsilon(4S)\) resonance with the Belle detector at the KEKB asymmetric-energy \(e^{+}e^{-}\) collider. The branching fraction is measured to be \(\mathcal{B}(B^{0} \to \eta \eta ) = (7.6^{+2.7 +1.4}_{-2.3 -1.6}) \times 10^{-7}\) at the level of 3.3 standard deviations above zero, which provides the first evidence for the decay \(B^{0} \to \eta \eta\).
We report the first measurement of the \(\tau\) lepton polarization in the decay \({\bar B} \rightarrow D^* \tau^- {\bar\nu_{\tau}}\) as well as a new measurement of the ratio of the branching ...fractions \(R(D^{*}) = \mathcal{B}({\bar B} \rightarrow D^* \tau^- {\bar\nu_{\tau}}) / \mathcal{B}({\bar B} \rightarrow D^* \ell^- {\bar\nu_{\ell}})\), where \(\ell^-\) denotes an electron or a muon, with the decays \(\tau^- \rightarrow \pi^- \nu_{\tau}\) and \(\tau^- \rightarrow \rho^- \nu_{\tau}\). We use the full data sample of \(772 \times 10^6\) \(B{\bar B}\) pairs accumulated with the Belle detector at the KEKB electron-positron collider. Our preliminary results, \(R(D^*) = 0.276 \pm 0.034{\rm (stat.)} ^{+0.029} _{-0.026}{\rm (syst.)}\) and \(P_{\tau} = -0.44 \pm 0.47 {\rm (stat.)} ^{+0.20} _{-0.17} {\rm (syst.)}\), are consistent with the theoretical predictions of the Standard Model within \(0.6\) standard deviation.
Observation of B + → p Λ ¯ π + π − at Belle Wang, M.-Z.; Bakich, A. M.; Balagura, V. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
12/2009, Letnik:
80, Številka:
11
Journal Article
We report the first observation of Y(5S) -> Y(1,2S) pi0 pi0 decays. Evidence for the Zb0(10610) with 4.9sigma significance is found in a Dalitz plot analysis of Y(5S) -> Y(2S) pi0 pi0 decays. The ...results are obtained with a 121.4 fb^-1 data sample collected with the Belle detector at the Y(5S) resonance at the KEKB asymmetric-energy e+e- collider.
We present a measurement of angular observables, \(P_4'\), \(P_5'\), \(P_6'\), \(P_8'\), in the decay \(B^0 \to K^\ast(892)^0 \ell^+ \ell^-\), where \(\ell^+\ell^-\) is either \(e^+e^-\) or ...\(\mu^+\mu^-\). The analysis is performed on a data sample corresponding to an integrated luminosity of \(711~\mathrm{fb}^{-1}\) containing \(772\times 10^{6}\) \(B\bar B\) pairs, collected at the \(\Upsilon(4S)\) resonance with the Belle detector at the asymmetric-energy \(e^+e^-\) collider KEKB. Four angular observables, \(P_{4,5,6,8}'\) are extracted in five bins of the invariant mass squared of the lepton system, \(q^2\). We compare our results for \(P_{4,5,6,8}'\) with Standard Model predictions including the \(q^2\) region in which the LHCb collaboration reported the so-called \(P_5'\) anomaly.
We report a measurement of ratio \({\cal R}(D^*) = {\cal B}(\bar{B}^0 \rightarrow D^{*+} \tau^- \bar{\nu}_{\tau})/{\cal B}(\bar{B}^0 \rightarrow D^{*+} \ell^- \bar{\nu}_{\ell})\), where \(\ell\) ...denotes an electron or a muon. The results are based on a data sample containing \(772\times10^6\) \(B\bar{B}\) pairs recorded at the \(\Upsilon(4S)\) resonance with the Belle detector at the KEKB \(e^+ e^-\) collider. We select a sample of \(B^0 \bar{B}^0\) pairs by reconstructing both \(B\) mesons in semileptonic decays to \(D^{*\mp} \ell^{\pm}\). We measure \({\cal R}(D^*)= 0.302 \pm 0.030({\rm stat)} \pm 0.011({\rm syst)}\), which is within \(1.6 \sigma\) of the Standard Model theoretical expectation, where \(\sigma\) is the standard deviation including systematic uncertainties.
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