23,623 research outputs found

    Orbifold quantum D-modules associated to weighted projective spaces

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    We construct in an abstract fashion the orbifold quantum cohomology (quantum orbifold cohomology) of weighted projective space, starting from the orbifold quantum differential operator. We obtain the product, grading, and intersection form by making use of the associated self-adjoint D-module and the Birkhoff factorization procedure. The method extends to the more difficult case of Fano hypersurfaces in weighted projective space. However, in contrast to the case of weighted projective space itself or a Fano hypersurface in projective space, a "small Birkhoff cell" can appear in the construction; we give an example of this phenomenon.Comment: 24 pages. The main modification in this (final) version is the description of an ambiguity in the example of section 5, which was omitted from the original versio

    Triangle singularities in B−→K−π−Ds0+B^-\rightarrow K^-\pi^-D_{s0}^+ and B−→K−π−Ds1+B^-\rightarrow K^-\pi^-D_{s1}^+

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    We study the appearance of structures in the decay of the B−B^- into K−π−Ds0+(2317)K^- \pi^- D_{s0}^+(2317) and K−π−Ds1+(2460)K^- \pi^- D_{s1}^+(2460) final states by forming invariant mass distributions of π−Ds0+\pi^- D_{s0}^+ and π−Ds1+\pi^- D_{s1}^+ pairs, respectively. The structure in the distribution is associated to the kinematical triangle singularity that appears when the B−→K−K∗ 0D0B^- \to K^- K^{*\,0} D^0 (B−→K−K∗ 0D∗ 0B^- \to K^- K^{*\,0} D^{*\,0}) decay process is followed by the decay of the K∗ 0K^{*\,0} into π−K+\pi^- K^+ and the subsequent rescattering of the K+D0K^+ D^0 (K+D∗ 0K^+ D^{*\,0}) pair forming the Ds0+(2317)D_{s0}^+(2317) (Ds1+(2460)D_{s1}^+(2460)) resonance. We find this type of non-resonant peaks at 2850 MeV in the invariant mass of π−Ds0\pi^- D_{s0} pairs from B−→K−π−Ds0+(2317)B^- \to K^- \pi^- D_{s0}^+(2317) decays and around 3000 MeV in the invariant mass of π−Ds1+\pi^- D_{s1}^+ pairs from B−→K−π−Ds1+(2460)B^- \to K^- \pi^- D_{s1}^+(2460) decays. By employing the measured branching ratios of the B−→K−K∗ 0D0B^- \to K^- K^{*\,0} D^0 and B−→K−K∗ 0D∗ 0B^- \to K^- K^{*\,0} D^{*\,0} decays, we predict the branching ratios for the processes B−B^- into K−π−Ds0+(2317)K^- \pi^-D_{s0}^+(2317) and K−π−Ds1+(2460)K^- \pi^- D_{s1}^+(2460), in the vicinity of the triangle singularity peak, to be about 8×10−68\times10^{-6} and 1×10−61\times 10^{-6}, respectively. The observation of this reaction would also give extra support to the molecular picture of the Ds0+(2317)D_{s0}^+(2317) and Ds1+(2460)D_{s1}^+(2460).Comment: 18 pages, 15 figures, accepted version for publication in Eur. Phys. J.

    An investigation of children's peer trust across culture: is the composition of peer trust universal?

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    The components of children's trust in same-gender peers (trust beliefs, ascribed trustworthiness, and dyadic reciprocal trust) were examined in samples of 8- to 11-year-olds from the UK, Italy, and Japan. Trust was assessed by children's ratings of the extent to which same-gender classmates kept promises and kept secrets. Social relations analyses confirmed that children from each country showed significant: (a) actor variance demonstrating reliable individual differences in trust beliefs, (b) partner variance demonstrating reliable individual differences in ascribed trustworthiness, and (c ) relationship variance demonstrating unique relationships between interaction partners. Cultural differences in trust beliefs and ascribed trustworthiness also emerged and these differences were attributed to the tendency for children from cultures that value societal goals to share personal information with the peer group

    Riccati Solutions of Discrete Painlev\'e Equations with Weyl Group Symmetry of Type E8(1)E_8^{(1)}

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    We present a special solutions of the discrete Painlev\'e equations associated with A0(1)A_0^{(1)}, A0(1)∗A_0^{(1)*} and A0(1)∗∗A_0^{(1)**}-surface. These solutions can be expressed by solutions of linear difference equations. Here the A0(1)A_0^{(1)}-surface discrete Painlev\'e equation is the most generic difference equation, as all discrete Painlev\'e equations can be obtained by its degeneration limit. These special solutions exist when the parameters of the discrete Painlev\'e equation satisfy a particular constraint. We consider that these special functions belong to the hypergeometric family although they seems to go beyond the known discrete and qq-discrete hypergeometric functions. We also discuss the degeneration scheme of these solutions.Comment: 22 page

    Single domain YBCO/Ag bulk superconductors fabricated by seeded infiltration and growth

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    We have applied the seeded infiltration and growth (IG) technique to the processing of samples containing Ag in an attempt to fabricate Ag-doped Y-Ba-Cu-O (YBCO) bulk superconductors with enhanced mechanical properties. The IG technique has been used successfully to grow bulk Ag-doped YBCO superconductors of up to 25 mm in diameter in the form of single grains. The distribution of Ag in the parent Y-123 matrix fabricated by the IG technique is observed to be at least as uniform as that in samples grown by conventional top seeded melt growth (TSMG). Fine Y-211 particles were observed to be embedded within the Y-123 matrix for the IG processed samples, leading to a high critical current density, Jc, of over 70 kA/cm2 at 77.3 K in self-field. The distribution of Y-211 in the IG sample microstructure, however, is inhomogeneous, which leads to a variation in the spatial distribution of Jc throughout the bulk matrix. A maximum-trapped field of around 0.43 T at 1.2 mm above the sample surface (i.e. including 0.7 mm for the sensor mould thickness) is observed at liquid nitrogen temperature, despite the relatively small grain size of the sample (20 mm diameter × 7 mm thickness)

    Neutron Skin Thickness of 90Zr Determined By Charge Exchange Reactions

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    Charge exchange spin-dipole (SD) excitations of 90Zr are studied by the 90Zr(p,n) and 90Zr(n,p) reactions at 300 MeV. A multipole decomposition technique is employed to obtain the SD strength distributions in the cross section spectra. For the first time, a model-independent SD sum rule value is obtained: 148+/-12 fm^2. The neutron skin thickness of 90Zr is determined to be 0.07+/-0.04 fm from the SD sum rule value.Comment: 4 pages, 2 figures, submitted to Phys. Rev.
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