19,610 research outputs found

    An improved study of the kappa resonance and the non-exotic ss wave πK\pi K scatterings up to s=2.1\sqrt{s}=2.1GeV of LASS data

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    We point out that the dispersion relation for the left hand cut integral presented in one of our previous paper (Nucl. Phys. {\bf A}733(2004)235) is actually free of subtraction constant, even for unequal mass elastic scatterings. A new fit to the LASS data~\cite{Aston} is performed and firm evidence for the existence of κ\kappa pole is found. The correct use of analyticity also put strong constraints on threshold parameters -- which are found to be in good agreement with those obtained from chiral theories. We also determined the pole parameters of K0∗(1430)K_0^*(1430) on the second sheet, and reconfirm the existence of K0∗(1950)K_0^*(1950) on the third sheet. We stress that the LASS data do not require them to have the twin pole structure of a typical Breit--Wigner resonance.Comment: 14 pages + 4 postscript figures; discussions largely expanded; references added; version to appear in NPA; title changed in the journa

    Ni/Ni3C Core-Shell Nanochains and Its Magnetic Properties: One-Step Synthesis at low temperature

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    One-dimensional Ni/Ni3C core-shell nanoball chains with an average diameter by around 30 nm were synthesized by means of a mild chemical solution method using a soft template of trioctylphosphineoxide (TOPO). It was revealed that the uniform Ni nanochains were capped with Ni3C thin shells by about 1 to 4 nm in thickness and each Ni core consists of polygrains. The coercivity of the core-shell nanochains is much enhanced (600 Oe at 5 K) and comparable with single Ni nanowires due to the one-dimensional shape anisotropy. Deriving from the distinctive structure of Ni core and Ni3C shell, this architecture may possess a possible bi-functionality. This unique architecture is also useful for the study on the magnetization reversal mechanism of one-dimensional magnetic nanostructure.Comment: 17 pages, 6 figur

    Suppressing longitudinal double-layer oscillations by using elliptically polarized laser pulses in the hole-boring radiation pressure acceleration regime

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    It is shown that well collimated mono-energetic ion beams with a large particle number can be generated in the hole-boring radiation pressure acceleration regime by using an elliptically polarized laser pulse with appropriate theoretically determined laser polarization ratio. Due to the J×B\bm{J}\times\bm{B} effect, the double-layer charge separation region is imbued with hot electrons that prevent ion pileup, thus suppressing the double-layer oscillations. The proposed mechanism is well confirmed by Particle-in-Cell simulations, and after suppressing the longitudinal double-layer oscillations, the ion beams driven by the elliptically polarized lasers own much better energy spectrum than those by circularly polarized lasers.Comment: 6 pages, 5 figures, Phys. Plasmas (2013) accepte

    The SO(5)\mathrm{SO}(5) Deconfined Phase Transition under the Fuzzy Sphere Microscope: Approximate Conformal Symmetry, Pseudo-Criticality, and Operator Spectrum

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    The deconfined quantum critical point (DQCP) is an example of phase transitions beyond the Landau symmetry breaking paradigm that attracts wide interest. However, its nature has not been settled after decades of study. In this paper, we apply the recently proposed fuzzy sphere regularization to study the SO(5)\mathrm{SO}(5) non-linear sigma model (NLσ\sigmaM) with a topological Wess-Zumino-Witten term, which serves as a dual description of the DQCP with an exact SO(5)\mathrm{SO}(5) symmetry. We demonstrate that the fuzzy sphere functions as a powerful microscope, magnifying and revealing a wealth of crucial information about the DQCP, ultimately paving the way towards its final answer. In particular, through exact diagonalization, we provide clear evidence that the DQCP exhibits approximate conformal symmetry. The evidence includes the existence of a conserved SO(5)\mathrm{SO}(5) symmetry current, a stress tensor, and integer-spaced levels between conformal primaries and their descendants. Most remarkably, we have identified 19 conformal primaries and their 82 descendants. Furthermore, by examining the renormalization group flow of the lowest symmetry singlet, we demonstrate that the DQCP is more likely pseudo-critical, with the approximate conformal symmetry plausibly emerging from nearby complex fixed points. Our computed primary spectrum also has important implications, including the conclusion that the SO(5)\mathrm{SO}(5) DQCP cannot describe a direct transition from the N\'eel to valence bond solid phase on the honeycomb lattice.Comment: 17 pages, 6 figures and 6 table
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