348 research outputs found

    Anapole moment of an exotic nucleus

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    We demonstrate that there is no appreciable enhancement of the anapole moment of 11^{11}Be. The effect of small energy intervals is compensated for by a small overlap of the halo neutron wave function with core.Comment: 5 pages, LaTe

    Evidence for CP Violation in B0 -> D+D- Decays

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    We report measurements of the branching fraction and CP violation parameters in B0 -> D+D- decays. The results are based on a data sample that contains 535 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain [1.97 +- 0.20 (stat) +- 0.20 (syst)] x 10^(-4) for the branching fraction of B0 -> D+D-. The measured values of the CP violation parameters are: S = -1.13 +- 0.37 +- 0.09, A = 0.91 +- 0.23 +- 0.06, where the first error is statistical and the second is systematic. We find evidence of CP violation in B0 -> D+D- at the 4.1 sigma confidence level. While the value of S is consistent with expectations from other measurements, the value of the parameter A favors large direct CP violation at the 3.2 sigma confidence level, in contradiction to Standard Model expectations.Comment: 12 pages, 3 figures, submitted to PR

    Search for CP Violation in the Decays D0KS0P0D^0\rightarrow K^0_S P^0

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    We have searched for CP violation in the decays D0KS0P0D^0\rightarrow K^0_S P^0 where P0P^0 denotes a neutral pseudo-scalar meson which is either a π0\pi^0, η\eta, or η\eta' using KEKB asymmetric-energy e+ee^+e^- collision data corresponding to an integrated luminosity of 791 fb1^{-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 D0KS0π0D^0\rightarrow K^0_S\pi^0 to date: ACPD0KS0π0=(0.28±0.19±0.10)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 D0KS0ηD^0\rightarrow K^0_S\eta and D0KS0ηD^0\rightarrow K^0_S\eta': ACPD0KS0η=(+0.54±0.51±0.16)A_{CP}^{D^0\rightarrow K^0_S\eta}=(+0.54\pm0.51\pm0.16)% and ACPD0KS0η=(+0.98±0.67±0.14)A_{CP}^{D^0\rightarrow K^0_S\eta'}=(+0.98\pm0.67\pm0.14)%, respectively

    Measurement Of |V_ub| From Inclusive Charmless Semileptonic B Decays

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    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

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

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    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

    Measurement of CP asymmetries in B0K0π0B^0 \to K^0\pi^0 decays

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    We report measurements of CP violation parameters in B0K0π0B^0 \to K^0 \pi^0 decays based on a data sample of 657×106BBˉ657 \times 10^6 B\bar{B} pairs collected with the Belle detector at the KEKB e+ee^+ e^- asymmetric-energy collider. We use B0KS0π0B^0 \to K^0_S \pi^0 decays for both mixing-induced and direct CPCP violating asymmetry measurements and B0KL0π0B^0 \to K^0_L \pi^0 decays for the direct CP violation measurement. The CP violation parameters obtained are sin2ϕ1eff=+0.67±0.31(stat)±0.08(syst)\sin 2 \phi_1^{\rm eff} = +0.67 \pm 0.31{(stat)} \pm 0.08 {(syst)} and AK0π0=+0.14±0.13(stat)±0.06(syst)\mathcal{A}_{K^0 \pi^0} = +0.14 \pm 0.13{(stat)} \pm 0.06 {(syst)}. The branching fraction of B0K0π0B^0 \to K^0 \pi^0 decay is measured to be B(B0K0π0)=(8.7±0.5(stat.)±0.6(syst.))×106\mathcal{B}(B^0 \to K^0 \pi^0) = (8.7\pm0.5 (\rm{stat.})\pm0.6 (\rm{syst.}))\times 10^{-6}. The observed AK0π0\mathcal{A}_{K^0 \pi^0} value differs by 1.9 standard deviations from the value expected from an isospin sum rule.Comment: 6 pages, 3 figure

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

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    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

    First Measurement of Inclusive B -> X_s eta Decays

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    We report a first measurement of inclusive B -> X_s eta decays, where X_s is a charmless state with unit strangeness. The measurement is based on a pseudo-inclusive reconstruction technique and uses a sample of 657 x 10^6 BB-bar pairs accumulated with the Belle detector at the KEKB e^+e^- collider. For M_{X_s} < 2.6 GeV/c^2, we measure a branching fraction of (26.1 +/- 3.0 (stat) +1.9 -2.1 (syst) +4.0 -7.1 (model)) x 10^-5 and a direct CP asymmetry of A_{CP} = -0.13 +/- 0.04 +0.02 -0.03. Over half of the signal occurs in the range M_{X_s} > 1.8 GeV/c^2.Comment: 6 pages, 1 figure, 1 table, submitted to Physical Review Letter

    Search for CP Violation in the Decay D+KS0K+D^+\rightarrow K^0_S K^+

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    We search for CP violation in the decay D+KS0K+D^+\rightarrow K^0_S K^+ using a data sample with an integrated luminosity of 977 fb1^{-1} collected with the Belle detector at the KEKB e+ee^+e^- asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in D+KS0K+D^+\rightarrow K^0_S K^+ decay is measured to be (0.25±0.28±0.14)(-0.25\pm0.28\pm0.14)%, which is the most sensitive measurement to date. After subtracting CP violation due to K0Kˉ0K^0-\bar{K}^0 mixing, the CP asymmetry in D+Kˉ0K+D^+\rightarrow\bar{K}^0 K^+ decay is found to be (+0.08±0.28±0.14)(+0.08\pm0.28\pm0.14)%.Comment: 15 pages, 4 figures, 1 table. Published in JHE

    Measurement of CP violating asymmetries in B^0 -> K^+K^- K^0_S decays with a time-dependent Dalitz approach

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    We report a measurement of CPCP violating asymmetries in B0(B0)K+KKS0B^0(\overline{B}^0) \to K^+ K^- K^0_S decays with a time-dependent Dalitz approach. This analysis is based on a data sample of 657×106657\times 10^6 BBB\overline{B} pairs accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct CPCP violation parameters, ϕ1eff\phi^{\rm eff}_1 and ACP{\cal A}_{CP} are obtained for B0ϕ(1020)KS0B^0 \to \phi(1020) K^0_S, B0f0(980)KS0B^0 \to f_0(980) K^0_S and other B0K+KKS0B^0 \to K^+ K^- K^0_S decays. We find four solutions that describe the data. There are \{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm 2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm 8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The values for the CPCP violating phase in B0ϕ(1020)KS0B^0\to \phi(1020) K^0_S are similar but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent ϕ1eff\phi^{\rm eff}_1 values for all three BB meson decay channels and none of them deviates significantly from the values measured in B(ccˉ)K0B \to (c\bar{c}) K^0 decays with the currently available statistics. In addition, we find no significant direct CPCP violation.Comment: submitted to PR
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