Search for CP Violation in the Decays D0→KS0P0D^0\rightarrow K^0_S P^0

We have searched for CP violation in the decays $D^0\rightarrow K^0_S P^0$ where $P^0$ denotes a neutral pseudo-scalar meson which is either a $\pi^0$, $\eta$, or $\eta'$ using KEKB asymmetric-energy $e^+e^-$ collision data corresponding to an integrated luminosity of 791 fb$^{-1}$ collected with the Belle detector. No evidence of significant CP violation is observed. We report the most precise CP asymmetry measurement in the decay $D^0\rightarrow K^0_S\pi^0$ to date: $A_{CP}^{D^0\rightarrow K^0_S\pi^0}=(-0.28\pm0.19\pm0.10)$. We also report the first measurements of CP asymmetries in the decays $D^0\rightarrow K^0_S\eta$ and $D^0\rightarrow K^0_S\eta'$: $A_{CP}^{D^0\rightarrow K^0_S\eta}=(+0.54\pm0.51\pm0.16)$ and $A_{CP}^{D^0\rightarrow K^0_S\eta'}=(+0.98\pm0.67\pm0.14)$, respectively

Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle

The cross section for e^+e^- to pi^+pi^-J/psi between 3.8 and 5.5 GeV/c^2 is measured using a 548 fb^{-1} data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c^2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower mass side of the 4.25 GeV enhancement.Comment: 11 pages, 5 figures, 2 tables; version to appear in PR

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

Measurement of Inclusive Radiative B-meson Decays with a Photon Energy Threshold of 1.7 GeV

Using 605/fb of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B to X_s gamma. For the lower photon energy thresholds of 1.7, 1.8, 1.9 and 2.0GeV, as defined in the rest frame of the B-meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7GeV threshold we obtain the partial branching fraction BF(B to X_s gamma) = (3.45 +/- 0.15 +/- 0.40) x 10^-4, where the errors are statistical and systematic.Comment: 9 pages, 3 figures, 2 table

Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions

We report measurements of CP violation parameters in B0->Ks pi0 gamma transitions based on a data sample of 535x10^6 BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. One neutral B meson is fully reconstructed in the B0->Ks pi0 gamma mode. The flavor of the accompanying B meson is identified from its decay products. For a Ks pi0 invariant mass up to 1.8 GeV/c^2, we obtain S = -0.10 +- 0.31 +- 0.07 and A = -0.20 +- 0.20 +- 0.06. For a Ks pi0 invariant mass near the K*0(892) resonance, we obtain S = -0.32 +0.36-0.33 +-0.05 and A=-0.20 +-0.24 +-0.05.Comment: 6 pages, 3 figures, accepted by PR

Observation of Bs0→J/ψf0(980)B_s^0\to J/\psi f_0(980) and Evidence for Bs0→J/ψf0(1370)B_s^0\to J/\psi f_0(1370)

We report the first observation of $B_s^0\to J/\psi f_0(980)$ and first evidence for $B_s^0\to J/\psi f_0(1370)$, which are CP eigenstate decay modes. These results are obtained from $121.4\;\mathrm{fb}^{-1}$ of data collected at the $\Upsilon(5S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. We measure the branching fractions $\mathcal{B}(B_s^0\to J/\psi f_0(980);f_0(980)\to\pi^+\pi^-)=(1.16^{+0.31}_{-0.19}(\mathrm{stat.})^{+0.15}_{-0.17}(\mathrm{syst.})^{+0.26}_{-0.18}(N_{B_s^{(*)}\bar B_s^{(*)}})) \times 10^{-4}$ with a significance of $8.4\sigma$, and $\mathcal{B}(B_s^0\to J/\psi f_0(1370);f_0(1370)\to\pi^+\pi^-)=(0.34^{+0.11}_{-0.14}(\mathrm{stat.})^{+0.03}_{-0.02}(\mathrm{syst.})^{+0.08}_{-0.05}(N_{B_s^{(*)}\bar B_s^{(*)}})) \times 10^{-4}$ with a significance of $4.2\sigma$. The last error listed is due to uncertainty in the number of produced $B_s^{(*)}\bar B_s^{(*)}$ pairs.Comment: 5 pages, 2 figures, 2 tables, published in PR

Search for TeV Scale Physics in Heavy Flavour Decays

The subject of heavy flavour decays as probes for physics beyond the TeV scale is covered from the experimental perspective. Emphasis is placed on the more traditional Beyond the Standard Model topics that have potential for impact in the short term, with the physics explained. We do unabashedly promote our own phemonenology work.Comment: 10 pages, 9 figures (now fixed); Submitted for the SUSY07 proceeding

Measurement Of |V_ub| From Inclusive Charmless Semileptonic B Decays

We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the CKM matrix element |Vub|, using a multivariate analysis method to access ~90% of the B -> Xu l nu phase space. This approach dramatically reduces the theoretical uncertainties from the b-quark mass and non-perturbative QCD compared to all previous inclusive measurements. The results are based on a sample of 657 million B -Bbar pairs collected with the Belle detector. We find that Delta BR(B -> Xu l nu; p^*B_l>1.0 GeV/c=1.963 x (1 +/- 0.088(stat.) +/- 0.081(sys.)) x 10^-3. Corresponding values of |Vub| are extracted using several theoretical calculations.Comment: 9 pages, 1 figure, 2 tables. Published in PR

Observation of B0 to p pbar K*0 with a large K*0 polarization

We observe the decay B0 to p pbar K*0 with a branching fraction of (1.18^{+0.29}_{-0.25} (stat.) \pm 0.11 (syst.)) \times 10^{-6}. The statistical significance is 7.2 sigma for the signal in the low ppbar mass region. We study the decay dynamics of B0 to p pbar K*0 and compare it with B+ to p pbar K*+. The K*0 meson is found to be almost 100% polarized (with a fraction of (101 \pm 13 \pm 3)% in the helicity zero state), while the K*+ meson has a (32 \pm 17 \pm 9)% fraction in the helicity zero state. The direct CP asymmetries for B0 to p pbar K*0 and B+ to p pbar K*+ are measured to be -0.08\pm 0.20\pm 0.02 and -0.01\pm 0.19\pm 0.02, respectively. We also study the characteristics of the low mass ppbar enhancements near threshold and the associated angular distributions. In addition, we report improved measurements of the branching fractions BF(B+ to p pbar K*+) = (3.38^{+0.73}_{-0.60} \pm 0.39) \times 10^{-6} and BF(B0 to p pbar K0) = (2.51^{+0.35}_{-0.29} \pm 0.21) \times 10^{-6}, which supersede our previous measurements. These results are obtained from a 492 fb^{-1} data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+ e^- collider.Comment: 11 pages, 4 figures (8 figure files), submitted to Phys.Rev.Let

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