Evidence for a new resonance and search for the Y(4140) in γγ→ϕJ/ψ\gamma \gamma \to \phi J/\psi

The process \gamma \gamma \to \phi \jpsi is measured for \phi \jpsi masses between threshold and 5 GeV/${\it c}^2$, using a data sample of 825 fb$^{-1}$ collected with the Belle detector. A narrow peak of $8.8^{+4.2}_{-3.2}$ events, with a significance of 3.2 standard deviations including systematic uncertainty, is observed. The mass and natural width of the structure (named X(4350)) are measured to be $(4350.6^{+4.6}_{-5.1}(\rm{stat})\pm 0.7(\rm{syst})) \hbox{MeV}/{\it c}^2$ and $(13^{+18}_{-9}(\rm{stat})\pm 4(\rm{syst})) \hbox{MeV}$, respectively. The product of its two-photon decay width and branching fraction to \phi\jpsi is $(6.7^{+3.2}_{-2.4}(\rm{stat}) \pm 1.1(\rm{syst})) \hbox{eV}$ for $J^P=0^+$, or $(1.5^{+0.7}_{-0.6}(\rm{stat}) \pm 0.3(\rm{syst})) \hbox{eV}$ for $J^P=2^+$. No signal for the Y(4140)\to \phi \jpsi structure reported by the CDF Collaboration in B\to K^+ \phi \jpsi decays is observed, and limits of \Gamma_{\gamma \gamma}(Y(4140)) \BR(Y(4140)\to\phi \jpsi)<41 \hbox{eV} for $J^P=0^+$ or $<6.0 \hbox{eV}$ for $J^P=2^+$ are determined at the 90% C.L. This disfavors the scenario in which the Y(4140) is a $D_{s}^{\ast+} {D}_{s}^{\ast-}$ molecule.Comment: 9 pages, 3 figures, publication in Phys. Rev. Lett. 104, 112004, 201

First Observation of Radiative B^0 -> \phi K^0 \gamma Decays and Measurements of Their Time-Dependent CP Violation

We report the first observation of the radiative decay B^0 -> \phi K^0 \gamma using a data sample of 772 x 10^6 B B-bar pairs collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a signal of 37+/-8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is ${\cal B}(B^0 -> \phi K^0 \gamma) = (2.74\pm 0.60 \pm 0.32) \times 10^{-6}$, where the uncertainties are statistical and systematic, respectively. We also report the first measurements of time-dependent CP violation parameters: ${\mathcal S}_{\phi K_S^0 \gamma} = +0.74^{+0.72}_{-1.05} (stat)^{+0.10}_{-0.24} (syst)$ and ${\mathcal A}_{\phi K_S^0 \gamma} = +0.35 +/- 0.58 (stat)^{+0.23}_{-0.10} (syst)$. Furthermore, we measure ${\mathcal B}(B^+ -> \phi K^+ \gamma) = (2.48 +/- 0.30 +/- 0.24) x 10^{-6}$, ${\mathcal A}_{CP} = -0.03 +/- 0.11 +/- 0.08$ and find that the signal is concentrated in the M_{\phi K} mass region near threshold.Comment: 6 pages, 3 figures, Modified version is to be published in PRD(RC

Measurement of the CP-violation Parameter sin2ϕ1\phi_1 with a New Tagging Method at the Υ(5S)\Upsilon(5S) Resonance

We report a measurement of the CP-violation parameter sin2$\phi_1$ at the $\Upsilon(5S)$ resonance using a new tagging method, called "$B$-$\pi$ tagging." In $\Upsilon(5S)$ decays containing a neutral $B$ meson, a charged $B$, and a charged pion, the neutral $B$ is reconstructed in the $J/\psi K_S^0$ CP-eigenstate decay channel. The initial flavor of the neutral $B$ meson at the moment of the $\Upsilon(5S)$ decay is opposite to that of the charged $B$ and may thus be inferred from the charge of the pion without reconstructing the charged $B$. From the asymmetry between $B$-$\pi^+$ and $B$-$\pi^-$ tagged $J/\psi K_S^0$ yields, we determine sin2$\phi_1$ = 0.57 $\pm$ 0.58(stat) $\pm$ 0.06(syst). The results are based on 121 fb$^{-1}$ of data recorded by the Belle detector at the KEKB $e^+ e^-$ collider.Comment: 6 pages, 3 figures (submitted to PRL

Search for CP Violation in D Meson Decays to phi pi+

We search for CP violation in Cabibbo-suppressed charged D meson decays by measuring the difference between the CP violating asymmetries for the Cabibbo-suppressed decays D+ -> K+K-pi+ and the Cabibbo-favored decays Ds -> K+K-pi+ in the K+K- mass region of the phi resonance. Using 955/fb of data collected with the Belle detector we obtain A_CP(D+ -> phi pi+) = (+0.51 +- 0.28 +- 0.05)%. The measurement improves the sensitivity of previous searches by more than a factor of five. We find no evidence for direct CP violation.Comment: submitted to PR

Observation of X(3872)→J/ψγX(3872)\to J/\psi \gamma and search for X(3872)→ψ′γX(3872)\to\psi'\gamma in B decays

We report a study of $B\to (J/\psi \gamma) K$ and $B\to (\psi' \gamma)K$ decay modes using $772\times 10^{6}$ $B\bar{B}$ events collected at the \Upsilon(4S)$resonance with the Belle detector at the KEKB energy-asymmetric$e^+ e^-$collider. We observe$X(3872) \to J/\psi \gamma$and report the first evidence for$\chi_{c2} \to J/\psi \gamma$in$B\to (X_{c\bar{c}}\gamma) K$decays, while in a search for$X(3872) \to \psi' \gamma$no significant signal is found. We measure the branching fractions,$\mathcal{B}(B^{\pm} \to X(3872) K^{\pm}) \mathcal{B}(X(3872) \to J/\psi\gamma)$$=$$(1.78^{+0.48}_{-0.44}\pm 0.12)\times 10^{-6}$,$\mathcal{B} (B^{\pm} \to\chi_{c2} K^{\pm})$$=$$(1.11^{+0.36}_{-0.34} \pm 0.09) \times 10^{-5}$,$\mathcal{B}(B^{\pm} \to X(3872) K^{\pm}) \mathcal{B}(X(3872) \to \psi'\gamma)$$<$$3.45\times 10^{-6}$ (upper limit at 90% C.L.) and also provide upper limits for other searches.Comment: 6 pages, 3 figure

Search for charmonium and charmonium-like states in \Upsilon(2S) radiative decays

Using a sample of 158 million \Upsilon(2S) events collected with the Belle detector, charmonium and charmonium-like states with even charge parity are searched for in \Upsilon(2S) radiative decays. No significant \chi_{cJ} or \eta_c signal is observed and the following upper limits at 90% confidence level (C.L.) are obtained: BR(\Upsilon(2S)\to \gamma \chi_{c0})< 1.0 \times 10^{-4}, BR(\Upsilon(2S) \to \gamma \chi_{c1})<3.6 \times 10^{-6}, BR(\Upsilon(2S) \to \gamma \chi_{c2})<1.5 \times 10^{-5}, and BR(\Upsilon(2S) \to \gamma \eta_c)< 2.7 \times 10^{-5}. No significant signal of any charmonium-like state is observed, and we obtain the limits \BR(\Upsilon(2S)\to \gamma X(3872))\times\BR(X(3872)\to\pi^+\pi^-J/\psi)< 0.8 \times 10^{-6}, BR(\Upsilon(2S) \to \gamma X(3872))\times BR(X(3872)\to\pi^+\pi^-\pi^0 J/\psi)< 2.4\times 10^{-6}, BR(\Upsilon(2S) \to \gamma X(3915))\times BR(X(3915)\to\omega J/\psi)< 2.8\times 10^{-6}, BR(\Upsilon(2S) \to \gamma Y(4140))\times BR(Y(4140)\to\phi J/\psi)) < 1.2\times 10^{-6}, and BR(\Upsilon(2S) \to \gamma X(4350))\times BR(X(4350)\to\phi J/\psi))< 1.3\times 10^{-6} at 90% C.L.Comment: 7 pages, 6 figures, 1 tabl

Observation of B+ -> Dbar*0 tau+ nu_tau and Evidence for B+ -> Dbar^0 tau+ nu_tau at Belle

We present measurements of B+ -> Dbar*0 tau+ nu_tau and B+ -> Dbar^0 tau+ nu_tau decays in a data sample of 657 x 10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find 446^{+58}_{-56} events of the decay B+ -> Dbar*0 tau+ nu_tau with a significance of 8.1 standard deviations, and 146^{+42}_{-41} events of the decay B+ -> Dbar0 tau+ nu_tau with a significance of 3.5 standard deviations. The latter signal provides the first evidence for this decay mode. The measured branching fractions are B(B+ -> Dbar*0 tau+ nu_tau)=(2.12^{+0.28}_{-0.27} (stat) +- 0.29 (syst)) % and B(B+ -> Dbar0 tau+ nu_tau)=(0.77 +- 0.22 (stat) +- 0.12 (syst)) %.Comment: 6 pages, 4 figures, submitted to Phys. Rev. Let

Bounds on the width, mass difference and other properties of X(3872) --> pi+pi-J/psi decays

We present results from a study of X(3872) --> pi+pi- J/psi decays produced via exclusive B--> K X(3872) decays. We determine the mass to be M_X(3872)= (3871.84\pm 0.27 (stat)\pm 0.19 (syst)) MeV, a 90% CL upper limit on the natural width of Gamma_X(3872) K+X(3872))xBf(X(3872)-->pi+pi-J/psi)=(8.61 \pm 0.82(stat) \pm 0.52 (syst)) x10^{-6}, and a ratio of branching fractions Bf(B0--> K0 X(3872))/BF(B+--> K+ X(3872))=0.50\pm 0.14(stat)\pm0.04(syst). The difference in mass between the X(3872)-->pi+pi-J/psi signals in B+ and B0 decays is Delta M_{X(3872)= (-0.69 \pm 0.97 (stat)} \pm 0.19 (syst)) MeV. A search for a charged partner of the X(3872) in the decays Bbar0-->K- X+ or B+-->K0X+, X+-->pi+pi0 J/psi resulted in upper limits on the product branching fractions for these processes that are well below expectations for the case that the X(3872) is the neutral member of an isospin triplet. In addition, we examine possible J^{PC} quantum number assignments for the X(3872) based on comparisons of angular correlations between final state particles in X(3872)-->pi+pi-J/psi decays with simulated data for J^{PC} values of 1^{++} and 2^{-+}. We examine the influence of rho-omega interference in the M(pi+pi-) spectrum. The analysis is based on a 711fb^{-1} data sample that contains 772 million BBbar meson pairs collected at the Upsilon(4S) resonance in the Belle detector at the KEKB e+e- collider.Comment: 15 pages, 10 figures and 6 tables. Submitted to Physical Review

Measurement of D+→KS0K+D^+ \to K_S^0 K^+ and Ds+→KS0π+D^+_s \to K_S^0 \pi^+ branching ratios

We report an improved measurement of $D^+ \to K_S^0 K^+$ and $D^+_s\to K_S^0 \pi^+$ branching ratios using 605 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The measured branching ratios with respect to the Cabibbo-favored modes are $\mathcal{B}(D^+ \to K_S^0 K^+)/\mathcal{B}(D^+ \to K_S^0 \pi^+)$ = 0.1899$\pm0.0011\pm$0.0022 and $\mathcal{B}(D^+_s \to K_S^0 \pi^+)/\mathcal{B}(D^+_s \to K_S^0 K^+)$ = 0.0803$\pm0.0024\pm$0.0019 where the first uncertainties are statistical and the second are systematic

Dalitz analysis of B --> K pi psi' decays and the Z(4430)+

From a Dalitz plot analysis of B --> K pi psi' decays, we find a signal for Z(4430)+ --> pi+ psi' with a mass M= (4443(+15-12)(+19-13))MeV/c^2, width Gamma= (107(+86-43)(+74-56))MeV, product branching fraction BR(B0 --> K- Z(4430)+) x BR(Z(4430)+ --> pi+ psi')= (3.2(+1.8-0.9)(+5.3-1.6)) x 10^{-5}, and significance of 6.4sigma that agrees with previous Belle measurements based on the same data sample. In addition, we determine the branching fraction BR(B^0 --> K*(892)^0 psi')= (5.52(+0.35-0.32)(+0.53-0.58)) x 10^{-4} and the fraction of K*(892)^0 mesons that are longitudinally polarized f_L= 44.8(+4.0-2.7)(+4.0-5.3)%. These results are obtained from a 605fb^{-1} data sample that contains 657 million B-anti-B pairs collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider.Comment: Final version published in PRD(RC