611 research outputs found

    The signal of Z±(4430)Z^\pm(4430) in nucleon-antinucleon scattering

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    We study the production of Z±(4430)Z^\pm(4430) at a nucleon-antinucleon scattering experiment. Considering the PANDA experiment to be an ideal platform to explore the production of the charmonium and charmonim-like states, we suggest the forthcoming PANDA experiment to pay attention to the production of Z±(4430)Z^\pm(4430).Comment: 6 pages, 15 figures. Published version in EPJ

    Understanding the newly observed Y(4008) by Belle

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    Very recently a new enhancement around 4.05 GeV was observed by Belle experiment. In this short note, we discuss some possible assignments for this enhancement, i.e. ψ(3S)\psi(3S) and DDˉD^*\bar{D}^* molecular state. In these two assignments, Y(4008) can decay into J/ψπ0π0J/\psi\pi^0\pi^0 with comparable branching ratio with that of Y(4008)J/ψπ+πY(4008)\to J/\psi\pi^+\pi^-. Thus one suggests high energy experimentalists to look for Y(4008) in J/ψπ0π0J/\psi\pi^0\pi^0 channel. Furthermore one proposes further experiments to search missing channel DDˉD\bar{D}, DDˉ+h.c.D\bar{D}^*+h.c. and especially χcJπ+ππ0\chi_{cJ}\pi^+\pi^-\pi^0 and ηcπ+ππ0\eta_c\pi^+\pi^-\pi^0, which will be helpful to distinguish ψ(3S)\psi(3S) and DDˉD^*\bar{D}^* molecular state assignments for this new enhancement.Comment: 4 pages, 5 figures. Typos correcte

    Non-Markovian dynamics in a spin star system: The failure of thermalization

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    In most cases, a small system weakly interacting with a thermal bath will finally reach the thermal state with the temperature of the bath. We show that this intuitive picture is not always true by a spin star model where non-Markov effect predominates in the whole dynamical process. The spin star system consists a central spin homogeneously interacting with an ensemble of identical noninteracting spins. We find that the correlation time of the bath is infinite, which implies that the bath has a perfect memory, and that the dynamical evolution of the central spin must be non- Markovian. A direct consequence is that the final state of the central spin is not the thermal state equilibrium with the bath, but a steady state which depends on its initial state.Comment: 8 page

    Magnetic rogue wave in a perpendicular anisotropic ferromagnetic nanowire with spin-transfer torque

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    We present the current controlled motion of dynamic soliton embedded in spin wave background in ferromagnetic nanowire. With the stronger breather character we get the novel magnetic rogue wave and clarify its formation mechanism. The generation of magnetic rogue wave is mainly arose from the accumulation of energy and magnons toward to its central part. We also observe that the spin-polarized current can control the exchange rate of magnons between envelope soliton and background, and the critical current condition is obtained analytically. Even more interesting is that the spin-transfer torque plays the completely opposite role for the cases of below and above the critical value.Comment: 5 figure

    Semileptonic decays of Bs1B_{s1}, Bs2B_{s2}^*, Bs0B_{s0} and Bs1B_{s1}'

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    Stimulated by recent observations of the excited bottom-strange mesons Bs1B_{s1} and Bs2B_{s2}^*, we calculate the semileptonic decays Bs0,Bs1,Bs1,Bs2[Ds(1968),Ds(2112),DsJ(2317),DsJ(2460)]νˉB_{s0}, B_{s1}^{\prime}, B_{s1}, B_{s2}^*\to [D_s(1968), D_{s}^*(2112), D_{sJ}(2317), D_{sJ}(2460)]\ell\bar{\nu}, which is relevant for the exploration of the potential of searching these semileptonic decays in experiment.Comment: 11 pages, 3 figures, 9 tables. More discussion added, some descriptions changed. The version to appear in EPJ

    f0(980) meson as a K bar K molecule in a phenomenological Lagrangian approach

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    We discuss a possible interpretation of the f0(980) meson as a hadronic molecule - a bound state of K and bar K mesons. Using a phenomenological Lagrangian approach we calculate the strong f0(980) to pi pi and electromagnetic f0(980) to gamma gamma decays. The compositeness condition provides a self-consistent method to determine the coupling constant between f0 and its constituents, K and bar K. Form factors governing the decays of the f0(980) are calculated by evaluating the kaon loop integrals. The predicted f0(980) to pi pi and f0(980) to gamma gamma decay widths are in good agreement with available data and results of other theoretical approaches.Comment: 21 pages, 11 figures, revised version accepted for publication in Eur. Phys. J.

    Influence of Yb:YAG laser beam parameters on Haynes 188 weld fusion zone microstructure and mechanical properties

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    The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm1, and spot sizes between 160 and 320 lm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min�1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties

    Parity nonconserving cold neutron-parahydrogen interactions

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    Three pion dominated observables of the parity nonconserving interactions between the cold neutrons and parahydrogen are calculated. The transversely polarized neutron spin rotation, unpolarized neutron longitudinal polarization, and photon-asymmetry of the radiative polarized neutron capture are considered. For the numerical evaluation of the observables, the strong interactions are taken into account by the Reid93 potential and the parity nonconserving interactions by the DDH model along with the two-pion exchange.Comment: 17 pages, 2 figure

    The 3D Structure of N132D in the LMC: A Late-Stage Young Supernova Remnant

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    We have used the Wide Field Spectrograph (WiFeS) on the 2.3m telescope at Siding Spring Observatory to map the [O III] 5007{\AA} dynamics of the young oxygen-rich supernova remnant N132D in the Large Magellanic Cloud. From the resultant data cube, we have been able to reconstruct the full 3D structure of the system of [O III] filaments. The majority of the ejecta form a ring of ~12pc in diameter inclined at an angle of 25 degrees to the line of sight. We conclude that SNR N132D is approaching the end of the reverse shock phase before entering the fully thermalized Sedov phase of evolution. We speculate that the ring of oxygen-rich material comes from ejecta in the equatorial plane of a bipolar explosion, and that the overall shape of the SNR is strongly influenced by the pre-supernova mass loss from the progenitor star. We find tantalizing evidence of a polar jet associated with a very fast oxygen-rich knot, and clear evidence that the central star has interacted with one or more dense clouds in the surrounding ISM.Comment: Accepted for Publication in Astrophysics & Space Science, 18pp, 8 figure
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