Using a sample of $771.6 times 10^{6}$ $Upsilon(4S)$ decays collected by the Belle experiment at the KEKB $e^+e^-$ collider, we observe for the first time the transition $Upsilon(4S) to eta h_b(1P)$ with the branching fraction ${cal B}[Upsilon(4S) to
eta h_b(1P)]= (2.18 pm 0.11 pm 0.18) times 10^{-3}$ and we measure the $h_b(1P)$ mass $M_{h_{b}(1P)} = (9899.3 pm 0.4 pm 1.0)$ MeV/$c^{2}$, corresponding to the hyperfine splitting $Delta M_{mathrm HF}(1P) = (0.6 pm 0.4 pm 1.0)$ MeV/$c^{2}$. Using the transition $h_b(1P) to gamma eta_b(1S)$, we measure the $eta_b(1S)$ mass $M_{eta_{b}(1S)} = (9400.7 pm 1.7 pm 1.6)$ MeV/$c^{2}$, corresponding to $Delta M_{mathrm HF}(1S) = (59.6 pm 1.7 pm 1.6)$ MeV/$c^{2}$, the $eta_b(1S)$ width $Gamma_{eta_{b}(1S)} = (8 ^{+6}_{-5} pm 5)$ MeV/$c^{2}$ and the branching fraction ${cal B}[h_b(1P) to gamma eta_b(1S)]= (56 pm 8 pm 4) %$.
We present an extraction of azimuthal correlations between two pairs of charged pions detected in opposite jets from electron-positron annihilation. These correlations may arise from the dependence of the di-pion fragmentation on the polarization of
the parent quark in the process $e^+e^- rightarrow q bar{q}$. Due to the correlation of the quark polarizations, the cross-section of di-pion pair production, in which the pion pairs are detected in opposite jets in a dijet event, exhibits a modulation in the azimuthal angles of the planes containing the hadron pairs with respect to the production plane. The measurement of this modulation allows access to combinations of fragmentation functions that are sensitive to the quarks transverse polarization and helicity. Within our uncertainties we do not observe a significant signal from the previously unmeasured helicity dependent fragmentation function $G_1^perp$. This measurement uses a dataset of 938~fb$^{-1}$ collected by the Belle experiment at or near $sqrt{s}approx10.58$ GeV.
We report a measurement of the time-dependent CP asymmetry of B0->D(*)CP h0 decays, where the light neutral hadron h0 is a pi0, eta or omega meson, and the neutral D meson is reconstructed in the CP eigenstates K+ K-, K0S pi0 or K0S omega. The measur
ement is performed combining the final data samples collected at the Y(4S) resonance by the BaBar and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain ( 471 +/- 3 ) x 10^6 BB pairs recorded by the BaBar detector and ( 772 +/- 11 ) x 10^6, BB pairs recorded by the Belle detector. We measure the CP asymmetry parameters -eta_f S = +0.66 +/- 0.10 (stat.) +/- 0.06 (syst.) and C = -0.02 +/- 0.07 (stat.) +/- 0.03 (syst.). These results correspond to the first observation of CP violation in B0->D(*)CP h0 decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.
We report improved measurements of the product branching fractions ${mathcal B}(B^+rightarrowbar{D}^0 D_{s0}^{*+} (2317))times{mathcal B}( D_{s0} ^{*+}(2317)rightarrow D_s^{+}pi^0) =(8.0^{+1.3}_{-1.2} pm 1.1 pm 0.4)times 10^{-4}$ and ${mathcal B}(B^0
rightarrow D^- D_{s0} ^{*+}(2317))times{mathcal B}(D_{s0}^{*+}(2317)rightarrow D_s^{+}pi^0) =(10.2^{+1.3}_{-1.2} pm 1.0 pm 0.4)times 10^{-4}$, where the first errors are statistical, the second are systematic and the third are from $D$ and $D_s$ branching fractions. In addition, we report negative results from a search for hypothesized neutral ($Z^0$) and doubly charged ($Z^{++}$) isospin partners of the $D_{s0}^{*+}(2317)$ and provide upper limits on the product branching fractions ${mathcal B}(B^0 rightarrow D^0 z^0)times{mathcal B}(z^0rightarrow D_s^{+}pi^-)$ and ${mathcal B}(B^+rightarrow D^- z^{++})times{mathcal B}(z^{++}rightarrow D_s^{+}pi^+)$ that are more than an order of magnitude smaller than theoretical expectations for the hypotheses that the $D_{s0} ^{*+}(2317)$ is a member of an isospin triplet. The analysis uses a 711 fb$^{-1}$ data sample containing 772 million $Bbar{B}$ meson pairs collected at the $Upsilon(4S)$ resonance in the Belle detector at the KEKB collider.
We report a search for the charmless hadronic decay $B^0toeta pi^0$ with a data sample corresponding to an integrated luminosity of 694 $rm fb^{-1}$ containing $753times10^6$ $Bbar{B}$ pairs. The data were collected by the Belle experiment running on
the $Upsilon(4S)$ resonance at the KEKB $e^+e^-$ collider. We measure a branching fraction $mathcal{B}(B^0toetapi^0)=(4.1^{+1.7+0.5}_{-1.5-0.7})times 10^{-7}$, where the first uncertainty is statistical and the second is systematic. Our measurement gives an upper limit of $mathcal{B}(B^0toetapi^0)<6.5times 10^{-7}$ at 90% confidence level. The signal has a significance of $3.0$ standard deviations and constitutes the first evidence for this decay mode.
We present a search for the rare leptonic decays $B^+ to e^+ u_e$ and $B^+ to mu^+ u_mu$, using the full $Upsilon(4S)$ data sample of $772times 10^6$ $Bbar{B}$ pairs collected with the Belle detector at the $rm {small KEKB}$ asymmetric-energy $e^+
e^-$ collider. One of the $B$ mesons from the $Upsilon(4S) to Bbar{B}$ decay is fully reconstructed in a hadronic mode, while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as ${cal B}(B^+ to e^+ u_e)<3.5times 10^{-6}$ and ${cal B}(B^+ to mu^+ u_mu)<2.7 times 10^{-6}$ at 90$%$ confidence level.
We report a measurement of the amplitude ratio $r_S$ of $B^0 to D^0K^{*0}$ and $B^0 to bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $Dto K_S^0pi^+pi^-$ decays. Using the full data sample of $772times10^6$ $Bbar{B}$ pairs
collected at the $Upsilon(4S)$ resonance with the Belle detector at KEKB accelerator the upper limit is $r_S < 0.87$ at the 68 % confidence level. This result is the first measurement of $r_S$ with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of $r_S$ indicates the sensitivity of the decay to $phi_3$ because the statistical uncertainty is proportional to $1/r_S$. The $r_S$ result is obtained from observables ($x_pm$, $y_pm$) begin{eqnarray} x_- &=& +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} pm0.0 y_- &=& -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} pm0.1 x_+ &=& +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} pm0.1 y_+ &=& +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} pm0.1 , end{eqnarray} where $x_pm = r_S cos(delta_S pm phi_3)$, $y_pm = r_S sin(delta_S pm phi_3)$ and $phi_3 (delta_S)$ are the weak (strong) phase difference between $B^0 to D^0K^{*0}$ and $B^0 to bar{D^0}K^{*0}$. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on $c_i$ and $s_i$ parameters measured by CLEO.
We search for the decay $B_{s}^{0}rightarrowgammagamma$ and measure the branching fraction for $B_{s}^{0}rightarrowphigamma$ using 121.4~$textrm{fb}^{-1}$ of data collected at the $Upsilon(mathrm{5}S)$ resonance with the Belle detector at the KEKB as
ymmetric-energy $e^{+}e^{-}$ collider. The $B_{s}^{0}rightarrowphigamma$ branching fraction is measured to be $(3.6 pm 0.5 (mathrm{stat.}) pm 0.3 (mathrm{syst.}) pm 0.6 (f_{s})) times 10^{-5}$, where $f_{s}$ is the fraction of $B_{s}^{(*)}bar{B}_{s}^{(*)}$ in $bbar{b}$ events. Our result is in good agreement with the theoretical predictions as well as with a recent measurement from LHCb. We observe no statistically significant signal for the decay $B_{s}^{0}rightarrowgammagamma$ and set a $90%$ confidence-level upper limit on its branching fraction at $ 3.1 times 10^{-6}$. This constitutes a significant improvement over the previous result.
We report a measurement of the $B^0$ and $B^+$ meson decays to the $D_s^-K^0_S pi^+$ and $D_s^- K^+K^+$ final states, respectively, using $657 times 10^{6} Boverline{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KE
KB asymmetric-energy $e^+e^-$ collider. Using the $D_s^-to phipi^-$, $K^{*}(892)^0 K^-$ and $K^0_S K^-$ decay modes for the $D_s$ reconstruction, we measure the following branching fractions: ${cal B}(B^0to D_s^{-}K^0_Spi^+)=[0.47 pm 0.06 (mathrm {stat}) pm 0.05 (mathrm {syst})]times 10^{-4}$ and ${cal B}(B^+to D_s^-K^+K^+)= [0.93 pm 0.22 (mathrm {stat})pm 0.10 (mathrm {syst})]times 10^{-5}$. We find the ratio of the branching fraction of $B^+to D_s^-K^+K^+$ to that of the analogous Cabibbo favored $B^+to D_s^-K^+pi^+$ decay to be ${cal R}_{cal B} = 0.054 pm 0.013 ({rm stat}) pm 0.006 ({rm syst})$, which is consistent with the na{i}ve factorization model. We also observe a deviation from the three-body phase-space model for both studied decays.
We report a measurement of the branching fraction of $B^+ to tau^+ u_tau$ decays using a data sample of $772 times 10^6 B bar{B}$ pairs, collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider
. We reconstruct the accompanying $B$ meson in a semileptonic decay and detect the $B^+ to tau^+ u_tau$ candidate in the recoiling event. We obtain a branching fraction of ${cal B}(B^+ to tau^+ u_tau) = [1.25 pm 0.28 ({rm stat.}) pm 0.27({rm syst.})] times 10^{-4}$. This result is in good agreement with previous measurements and the expectation from calculations based on the Standard Model.
