Publications (247)554.1 Total impact

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ABSTRACT: We report on the first observations of $\bar{B}^0 \to D_1(2430)^0 \omega$, $\bar{B}^0 \to D_1(2420)^0 \omega$ and $\bar{B}^0 \to D^*_2(2460)^0 \omega$ decays. The $\bar{B}^0 \to D^{*+} \rho(1450)^$ decay is also observed. The branching fraction measurements are based on $(771.6 \pm 10.6)\times 10^6$ $B\bar{B}$ events collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. The fractions of longitudinal polarization of the $D^{**}$ states as well as partial wave fractions of the $D_1(2430)^0$ are obtained. We also set a $90\%$ confidence level upper limit for the product of branching fractions of $\mathcal{B}(\bar{B}^0 \to D^{*+} b_1(1235)^) \times \mathcal{B}(b_1(1235)^ \to \omega \pi^)$. The measurements show evidence of nontrivial finalstate interaction phases for the $\rho$like amplitudes. 
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ABSTRACT: We search for the decay B+ > l+ nu gamma with l+ = e+ or mu+ using the full Belle data set of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetricenergy e+e collider. We reconstruct one B meson in a hadronic decay mode and search for the B+ > l+ nu gamma decay in the remainder of the event. We observe no significant signal within the phase space of E_gamma^sig > 1 GeV and obtain upper limits of BR(B+ > e+ nu gamma) < 6.1 x 10^6, BR(B+ > mu+ nu gamma) < 3.4 x 10^6, and BR(B+ > l+ nu gamma) < 3.5 x 10^6 at 90 % credibility level. 
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ABSTRACT: We report improved measurements of the product branching fractions ${\mathcal B}(B^+\rightarrow\bar{D}^0 D_{s0}^{*+} (2317))\times{\mathcal B}( D_{s0} ^{*+}(2317)\rightarrow D_s^{+}\pi^0) =(8.0^{+1.3}_{1.2} \pm 1.1 \pm 0.4)\times 10^{4}$ 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 ${\mathcal B}(B^0 \rightarrow D^0 z^0)\times{\mathcal B}(z^0\rightarrow D_s^{+}\pi^)$ and ${\mathcal B}(B^+\rightarrow D^0 z^{++})\times{\mathcal B}(z^{++}\rightarrow D_s^{+}\pi^+)$ 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 $B\bar{B}$ meson pairs collected at the $\Upsilon(4S)$ resonance in the Belle detector at the KEKB collider. 
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ABSTRACT: We present an analysis of the semiinclusive decays $B_s \to D_s^ X \ell^+ \nu$ and $B_s \to D_s^{*} X \ell^+ \nu$, where $X$ denotes a final state that may consist of additional hadrons or photons and $\ell$ is an electron or muon. The studied $B_s$ decays are contained in the $121.4~{\rm fb}^{1}$ $\Upsilon(5S)$ data sample collected by the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. The branching fractions of the decays are measured to be $\mathcal{B}(B_s \to D_s^ X \ell^+ \nu) = [8.2 \pm 0.2 (\text{stat}) \pm 0.6 (\text{syst}) \pm 1.4 (\text{ext})]\%$ and $\mathcal{B}(B_s \to D_s^{*} X \ell^+ \nu) = [5.4 \pm 0.4 (\text{stat}) \pm 0.4 (\text{syst}) \pm 0.9 (\text{ext})]\%$, where the first two uncertainties are statistical and systematic and the last is due to external parameters. The measurement also provides an estimate of the $B_s^{(*)}\bar{B}_s^{(*)}$ production crosssection, $\sigma(e^+e^ \to B_s^{(*)}\bar{B}_s^{(*)}) = (57.1 \pm 1.5 (\text{stat}) \pm 4.3 (\text{syst}) \pm 4.2 (\text{ext}))\,{\rm pb}$, at the centerofmass energy $\sqrt{s} = 10.86\,{\rm GeV}$. 
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ABSTRACT: We report a search for the charmless hadronic decay B0 > \eta \pi^0 with a data sample corresponding to an integrated luminosity of 694 fb^{1} containing 753\times 10^6 B\bar{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^0\to\eta\pi^0)=(4.1^{+1.7+0.5}_{1.50.7})\times 10^{7}, where the first uncertainty is statistical and the second is systematic. Our measurement gives an upper limit of \mathcal{B}(B^0\to\eta\pi^0)<6.5\times 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. 
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ABSTRACT: We report a measurement of the branching fraction of B^+ > tau^+ nu_tau decays using a data sample of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetricenergy e^+e^ collider. We reconstruct the accompanying B meson in a semileptonic decay and detect the recoiling B candidate in the decay channel B^+ > tau^+ nu_tau. We obtain a branching fraction of BR(B^+ > tau^+ nu_tau) = [1.25 + 0.28 (stat.) + 0.27 (syst.)] x 10^4. This result is in good agreement with previous measurements and the expectation from the calculation based on the Standard Model. 
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ABSTRACT: We report a search for the rare charmless decay $B^+\rightarrow\overline{K}{}^{*0}K^{*+}$ using a data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. No statistically significant signal is found and a 90% confidencelevel upper limit is set on the decay branching fraction as $ \mathcal{B}(B^+\rightarrow\overline{K}{}^{*0}K^{*+}) <1.31\times 10^{6}$. 
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ABSTRACT: We report a search for $B$ decays to selected final states with the $\eta_c$ meson: $B^{\pm}\to K^{\pm}\eta_c\pi^+\pi^$, $B^{\pm}\to K^{\pm}\eta_c\omega$, $B^{\pm}\to K^{\pm}\eta_c\eta$ and $B^{\pm}\to K^{\pm}\eta_c\pi^0$. The analysis is based on $772\times 10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ 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 $(0.65.3)\times 10^{4}$. We also search for molecularstate candidates for the $D^0\bar{D}^{*0}\bar{D}^0D^{*0}$, $D^0\bar{D}^0+\bar{D}^0D^0$ and $D^{*0}\bar{D}^{*0}+\bar{D}^{*0}D^{*0}$ combinations, neutral partners of the $Z(3900)^{\pm}$ and $Z(4020)^{\pm}$, 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 $X$ and decay branching fractions of $X$ in the range $(0.66.9)\times 10^{5}$. 
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ABSTRACT: We report the measurement of the direct $CP$ asymmetry in the radiative $\bar{B}\rightarrow X_{s+d}\gamma$ decay using a data sample of $(772 \pm 11)\times 10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. The $CP$ asymmetry is measured as a function of the photon energy threshold. For $E^{\rm{*}}_{\gamma} \geq 2.1~{\rm{GeV}}$, where $E^{\rm{*}}_{\gamma}$ is the photon energy in the centerofmass frame, we obtain $\mathcal{A}_{CP}(\bar{B}\rightarrow X_{s+d}\gamma)= (2.2 \pm 3.9 \pm 0.9) \%$, consistent with the Standard Model prediction. 
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ABSTRACT: We report new measurements of $R_{\Upsilon\pi\pi}\equiv\sigma(e^+e^\to \Upsilon(n{\rm S})\pi^+\pi^)/\sigma^0_{\mu\mu}$ ($n$ = 1, 2, 3) and $R_b\equiv\sigma(e^+e^\to b\bar b)/\sigma^0_{\mu\mu}$ (where $\sigma^0_{\mu\mu}$ is the muonpair Born cross section) in the region $\sqrt{s} = 10.63$$11.05$ GeV, based on data collected with the Belle detector. Distributions in $R_{\Upsilon\pi\pi}$ and $R_b$ are fit for the masses and widths of the $\Upsilon(10860)$ and $\Upsilon(11020)$ resonances. Unlike $R_b$, which includes a large nonresonant $b\bar{b}$ component, we find that $R_{\Upsilon\pi\pi}$ is dominated by the two resonances. With $R_{\Upsilon\pi\pi}$ as the basis, the total rate at the $\Upsilon(10860)$ peak for known final states containing bottomonium(like) resonances is estimated. We find that $\Upsilon(10860)$ is essentially saturated by such modes, raising doubts about the validity of masses measured using $R_b$. With $R_{\Upsilon\pi\pi}$, we measure $M_{10860}=(10891.1\pm3.2^{+0.6}_{1.5})$ MeV/$c^2$ and $\Gamma_{10860}=(53.7^{+7.1}_{5.6}\,^{+0.9}_{5.4})$ MeV and report first measurements $M_{11020}=(10987.5^{+6.4}_{2.5}\,^{+9.0}_{2.1})$ MeV/$c^2$, $\Gamma_{11020}=(61^{+9}_{19}\,^{+2}_{20})$ MeV, and the relative phase $\phi_{\rm 11020}\phi_{\rm 10860} = (1.0\pm0.4\,^{+1.0}_{0.1})$ rad. 
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ABSTRACT: We search for the decay $B_{s}^{0}\rightarrow\gamma\gamma$ and measure the branching fraction for $B_{s}^{0}\rightarrow\phi\gamma$ using 121.4~$\textrm{fb}^{1}$ of data collected at the $\Upsilon(\mathrm{5}S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^{+}e^{}$ collider. The $B_{s}^{0}\rightarrow\phi\gamma$ 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 $b\bar{b}$ 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 $B_{s}^{0}\rightarrow\gamma\gamma$ and set a $90\%$ confidencelevel upper limit on its branching fraction at $ 3.1 \times 10^{6}$. This constitutes a significant improvement over the previous result. 
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ABSTRACT: We use 772$\times 10^6$ $B \bar{B}$ meson pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector to measure the branching fraction for $\bar{B} \rightarrow X_s \gamma$. Our measurement uses a sumofexclusives approach in which 38 of the hadronic final states with strangeness equal to $+1$, denoted by $X_s$, are reconstructed. The inclusive branching fraction for $M_{X_s}<$ 2.8 GeV/$c^2$, which corresponds to a minimum photon energy of 1.9 GeV, is measured to be ${\cal B}(\bar{B} \rightarrow X_s \gamma)=(3.51\pm0.17\pm0.33)\times10^{4}$, where the first uncertainty is statistical and the second is systematic. 
Article: The Physics of the B Factories
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ABSTRACT: This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C.European Physical Journal C 11/2014; DOI:10.1140/epjc/s1005201430269 · 5.44 Impact Factor 
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ABSTRACT: 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 $657 \times 10^{6} B\overline{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. Using the $D_s^\to \phi\pi^$, $K^{*}(892)^0 K^$ and $K^0_S K^$ decay modes for the $D_s$ reconstruction, we measure the following branching fractions: ${\cal B}(B^0\to D_s^{}K^0_S\pi^+)=[0.47 \pm 0.06 (\mathrm {stat}) \pm 0.05 (\mathrm {syst})]\times 10^{4}$ 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 threebody phasespace model for both studied decays. 
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ABSTRACT: We report measurement of the cross section of $e^+e^\to \pi^+\pi^\psi(2S)$ between 4.0 and $5.5 {\rm GeV}$, based on an analysis of initial state radiation events in a $980 \rm fb^{1}$ data sample recorded with the Belle detector. The properties of the $Y(4360)$ and $Y(4660)$ states are determined. Fitting the mass spectrum of $\pi^+\pi^\psi(2S)$ with two coherent BreitWigner functions, we find two solutions with identical mass and width but different couplings to electronpositron pairs: $M_{Y(4360)} = (4347\pm 6\pm 3) {\rm MeV}/c^2$, $\Gamma_{Y(4360)} = (103\pm 9\pm 5) {\rm MeV}$, $M_{Y(4660)} = (4652\pm10\pm 8) {\rm MeV}/c^2$, $\Gamma_{Y(4660)} = (68\pm 11\pm 1) \rm MeV$; and ${\cal{B}}[Y(4360)\to \pi^+\pi^\psi(2S)]\cdot \Gamma_{Y(4360)}^{e^+e^} = (10.9\pm 0.6\pm 0.7) \rm eV$ and ${\cal{B}}[Y(4660)\to \pi^+\pi^\psi(2S)]\cdot \Gamma_{Y(4660)}^{e^+e^} = (8.1\pm 1.1\pm 0.5) \rm eV$ for one solution; or ${\cal{B}}[Y(4360)\to \pi^+\pi^\psi(2S)]\cdot \Gamma_{Y(4360)}^{e^+e^} = (9.2\pm 0.6\pm 0.6) \rm eV$ and ${\cal{B}}[Y(4660)\to \pi^+\pi^\psi(2S)]\cdot \Gamma_{Y(4660)}^{e^+e^} = (2.0\pm 0.3\pm 0.2) \rm eV$ for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at $4.05 {\rm GeV}/c^2$ is observed in the $\pi^{\pm}\psi(2S)$ intermediate state in the $Y(4360)$ decays. 
Article: Observation of e^{+}e^{}→π^{+}π^{}π^{0}χ_{bJ} and Search for X_{b}→ωϒ(1S) at sqrt[s]=10.867 GeV.
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ABSTRACT: The e^{+}e^{}→π^{+}π^{}π^{0}χ_{bJ} (J=0,1,2) processes are studied using a 118 fb^{1} data sample acquired with the Belle detector at a centerofmass energy of 10.867 GeV. Unambiguous π^{+}π^{}π^{0}χ_{bJ} (J=1,2), ωχ_{b1} signals are observed, and indication for ωχ_{b2} is seen, both for the first time, and the corresponding cross section measurements are presented. No significant π^{+}π^{}π^{0}χ_{b0} or ωχ_{b0} signals are observed, and 90% confidence level upper limits on the cross sections for these two processes are obtained. In the π^{+}π^{}π^{0} invariant mass spectrum, significant nonω signals are also observed. We search for the X(3872)like state (named X_{b}) decaying into ωϒ(1S); no significant signal is observed with a mass between 10.55 and 10.65 GeV/c^{2}.Physical Review Letters 10/2014; 113(14):142001. · 7.73 Impact Factor 
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ABSTRACT: Using data samples of $102\times10^6$ $\Upsilon(1S)$ and $158\times10^6$ $\Upsilon(2S)$ events collected with the Belle detector, a first experimental search has been made for doublecharmonium production in the exclusive decays $\Upsilon(1S,2S)\rightarrow J/\psi(\psi')+X$, where $X=\eta_c$, $\chi_{cJ} (J=~0,~1,~2)$, $\eta_c(2S)$, and X(3940). No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/\psi$ or $\psi'$ except for the evidence of $\chi_{c1}$ production with a significance of $4.6\sigma$ for $\Upsilon(1S)\rightarrow J/\psi+\chi_{c1}$. The measured branching fraction $\BR(\Upsilon(1S)\rightarrow J/\psi+\chi_{c1})$ is $(3.98\pm1.24(\rm stat.)\pm0.22 (\rm syst.))\times10^{6}$. The 90% confidence level upper limits on the branching fractions of the other modes having a significance of less than $3\sigma$ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach. 
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ABSTRACT: We report a measurement of the branching fraction of $B^+ \to \tau^+ \nu_\tau$ 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 asymmetricenergy $e^+e^$ collider. We reconstruct the accompanying $B$ meson in a semileptonic decay and detect the $B^+ \to \tau^+ \nu_\tau$ candidate in the recoiling event. We obtain a branching fraction of ${\cal B}(B^+ \to \tau^+ \nu_\tau) = [1.25 \pm 0.28 ({\rm stat.}) \pm 0.27({\rm syst.})] \times 10^{4}$. This result is in good agreement with previous measurements and the expectation from calculations based on the Standard Model. 
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ABSTRACT: We present the results of an amplitude analysis of B0 > J/psi K+ pi decays. A new charged charmoniumlike state Zc(4200)+ decaying to J/psi pi+ is observed with a significance of 6.2 sigma. The mass and width of the Zc(4200)+ are 4196 +3129 +1713 MeV/c^2 and 370 +7070 +70132 MeV, respectively; the preferred assignment of the quantum numbers is J^P = 1^+. In addition, we find evidence for Zc(4430)+ > J/psi pi+. The analysis is based on a 711 fb^1 data sample collected by the Belle detector at the asymmetricenergy e+ e collider KEKB. 
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ABSTRACT: We report a search for charmless hadronic decays of neutral $B$ mesons to $\eta' K^{*}(892)^{0}$. The results are based on a 711fb$^{1}$ data sample that contains $772\times 10^6 B\overline{B}$ pairs, collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^$ collider. We observe the decay for the first time with a significance of 5.0 standard deviations and obtain its branching fraction ${\cal B}[B^0\to\eta' K^{*}(892)^{0}]=[2.6\pm0.7{\rm (stat)}\pm0.2{\rm (syst)}]\times 10^{6}$. We also measure the $CP$ violating asymmetry as ${\cal A}_{CP}[B^0\to\eta' K^{*}(892)^{0}]=0.22\pm0.29{\rm (stat)}\pm0.07{\rm syst}$.
Publication Stats
3k  Citations  
554.10  Total Impact Points  
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Institutions

2007–2014

Charles University in Prague
 • Faculty of Mathematics and Physics
 • Institute of Particle and Nuclear Physics
Praha, Praha, Czech Republic


2013

University of Illinois, UrbanaChampaign
Urbana, Illinois, United States 
Nara Women's University
Nara, Nara, Japan 
High Energy Accelerator Research Organization
 Institute of Particle and Nuclear Studies
Tsukuba, Ibaraki, Japan


2012

Jožef Stefan Institute
Lubliano, Ljubljana, Slovenia 
Tohoku University
 Research Center for Electron Photon Science
Sendai, Kagoshimaken, Japan 
Institute for Theoretical and Experimental Physics
Moskva, Moscow, Russia 
National Taiwan University
 Department of Physics
Taipei, Taipei, Taiwan


2011–2012

University of Seoul
Sŏul, Seoul, South Korea 
Università di Pisa
 Department of Physics "E.Fermi"
Pisa, Tuscany, Italy


2010–2012

University of Freiburg
 Faculty of Mathematics and Physics
Freiburg, Lower Saxony, Germany 
Technische Universität Dortmund
 Chair of Experimental Physics I
Dortmund, North RhineWestphalia, Germany 
University of Cincinnati
 Department of Physics
Cincinnati, Ohio, United States
