54,034 research outputs found

    Heavy quark spin symmetric molecular states from Dˉ(∗)Σc(∗){\bar D}^{(*)}\Sigma_c^{(*)} and other coupled channels in the light of the recent LHCb pentaquarks

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    We consider the Dˉ(∗)Σc(∗){\bar D}^{(*)}\Sigma_c^{(*)} states, together with J/ψNJ/\psi N and other coupled channels, and take an interaction consistent with heavy quark spin symmetry, with the dynamical input obtained from an extension of the local hidden gauge approach. By fitting only one parameter to the recent three pentaquark states reported by the LHCb collaboration, we can reproduce the three of them in base to the mass and the width, providing for them the quantum numbers and approximate molecular structure as 1/2−1/2^- DˉΣc\bar{D} \Sigma_c, 1/2−1/2^- Dˉ∗Σc\bar{D}^* \Sigma_c, and 3/2−3/2^- Dˉ∗Σc\bar{D}^* \Sigma_c, and isospin I=1/2I=1/2. We find another state around 4374 MeV, of 3/2−3/2^- DˉΣc∗\bar{D} \Sigma_c^* structure, for which indications appear in the experimental spectrum. Two other near degenerate states of 1/2−1/2^- Dˉ∗Σc∗\bar{D}^* \Sigma_c^* and 3/2−3/2^- Dˉ∗Σc∗\bar{D}^* \Sigma_c^* nature are also found around 4520 MeV, which although less clear, are not incompatible with the observed spectrum. In addition, a 5/2−5/2^- Dˉ∗Σc∗\bar D^* \Sigma_c^* state at the same energy appears, which however does not couple to J/ψpJ/\psi p in S−S-wave, and hence it is not expected to show up in the LHCb experiment.Comment: 8 page

    Stray field and superconducting surface spin valve effect in La0.7_{0.7}Ca0.3_{0.3}MnO3_3/YBa2_2Cu3_3O7−δ_{7-\delta} bilayers

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    Electronic transport and magnetization measurements were performed on La0.7_{0.7}Ca0.3_{0.3}MnO3_3/YBa2_2Cu3_3O7−δ_{7-\delta} (LCMO/YBCO) bilayers below the superconducting transition temperature in order to study the interaction between magnetism and superconductivity. This study shows that a substantial number of weakly pinned vortices are induced in the YBCO layer by the large out-of-plane stray field in the domain walls. Their motion gives rise to large dissipation peaks at the coercive field. The angular dependent magnetoresistance (MR) data reveal the interaction between the stripe domain structure present in the LCMO layer and the vortices and anti-vortices induced in the YBCO layer by the out-of-plane stray field. In addition, this study shows that a superconducting surface spin valve effect is present in these bilayers as a result of the relative orientation between the magnetization at the LCMO/YBCO interface and the magnetization in the interior of the LCMO layer that can be tuned by the rotation of a small HH. This latter finding will facilitate the development of superconductive magnetoresistive memory devices. These low-magnetic field MR data, furthermore, suggest that triplet superconductivity is induced in the LCMO layer, which is consistent with recent reports of triplet superconductivity in LCMO/YBCO/LCMO trilayers and LCMO/YBCO bilayers.Comment: 14 pages, 3 figure

    Superconducting Surface Impedance under Radiofrequency Field

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    Based on BCS theory with moving Cooper pairs, the electron states distribution at 0K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor under radiofrequency (RF) field. We present the numerical results for Nb and compare these with representative RF field-dependent effective surface resistance measurements from a 1.5 GHz resonant structure

    Non-Universality of Transverse Momentum Dependent Parton Distributions at Small-x

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    We study the universality issue of the transverse momentum dependent parton distributions at small-x, by comparing the initial/final state interaction effects in dijet-correlation in pA collisions with those in deep inelastic lepton nucleus scattering. We demonstrate the non-universality by performing an explicit calculation in a particular model where the multiple gauge boson exchange contributions are summed up to all orders. We comment on the implications of our results on the theoretical interpretation of di-hadron correlation in dA collisions in terms of the saturation phenomena in deep inelastic lepton nucleus scattering.Comment: 11 pages, 3 figure

    B\"{a}cklund transformations for the constrained dispersionless hierarchies and dispersionless hierarchies with self-consistent sources

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    The B\"{a}cklund transformations between the constrained dispersionless KP hierarchy (cdKPH) and the constrained dispersionless mKP hieararchy (cdmKPH) and between the dispersionless KP hieararchy with self-consistent sources (dKPHSCS) and the dispersionless mKP hieararchy with self-consistent sources (dmKPHSCS) are constructed. The auto-B\"{a}cklund transformations for the cdmKPH and for the dmKPHSCS are also formulated.Comment: 11 page

    Shifting the Quantum-Classical Boundary: Theory and Experiment for Statistically Classical Optical Fields

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    The growing recognition that entanglement is not exclusively a quantum property, and does not even originate with Schr\"odinger's famous remark about it [Proc. Camb. Phil. Soc. 31, 555 (1935)], prompts examination of its role in marking the quantum-classical boundary. We have done this by subjecting correlations of classical optical fields to new Bell-analysis experiments, and report here values of the Bell parameter greater than B=2.54{\cal B} = 2.54. This is many standard deviations outside the limit B=2{\cal B} = 2 established by the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality [Phys. Rev. Lett. 23, 880 (1969)], in agreement with our theoretical classical prediction, and not far from the Tsirelson limit B=2.828...{\cal B} = 2.828.... These results cast a new light on the standard quantum-classical boundary description, and suggest a reinterpretation of it.Comment: Comments and Remarks are warmly welcome! arXiv admin note: text overlap with arXiv:1406.333
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