270 research outputs found

    Trace Anomaly of Proton Mass with Vector Meson Near-Thresholds Photoproduction Data

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    Trace anomalous contribution to proton mass is particularly important in understanding the QCD mass structure. The value and the scale-dependent of the trace anomalous energy of the strong interaction are still not clear in combination of theories and experiments. In this paper, we explore the near-threshold photoproduction data of ϕ\phi and J/ψ\psi to study the quantum anomalous energy in QCD and its scale-dependence. The vector-meson-dominance model and the van der Waals interaction between the vector meson and the proton are used. We find that the quantum anomalous energy to the proton mass is scale-dependent and it can be described as Ma=0.25exp(A/μ2)MNM_a=0.25\exp(-A/\mu^2)M_N with A=0.101±0.029A=0.101\pm0.029 GeV2^2. The empirical result is consistent with the LQCD calculation at μ2=4\mu^2=4 GeV2^2. Finally, the corresponding evolution equation for trace anomaly part is given by our calculation.Comment: 6 pages, 4 figures, Corrected spelling mistake

    Non-equilibrium dynamics of simple spherical spin models

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    We investigate the non-equilibrium dynamics of spherical spin models with two-spin interactions. For the exactly solvable models of the d-dimensional spherical ferromagnet and the spherical Sherrington-Kirkpatrick model the asymptotic dynamics has for large times and for large waiting times the same formal structure. In the limit of large waiting times we find in both models an intermediate time scale, scaling as a power of the waiting time with an exponent smaller than one, and thus separating the time-translation invariant short-time dynamics from the aging regime. It is this time scale on which the fluctuation-dissipation regime is violated. Aging in these models is similar to that observed in spin glasses at the level of correlation functions, but different at the level of response functions, and thus different at the level of experimentally accessible quantities like the thermoremanent magnetization.Comment: 8 pages, 1 eps figur

    Resonant quantum coherence of magnetization at excited states in nanospin systems with different crystal symmetries

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    The quantum interference effects induced by the Wess-Zumino term, or Berry phase are studied theoretically in resonant quantum coherence of magnetization vector between degenerate excited states in nanometer-scale single-domain ferromagnets in the absence of an external magnetic field. By applying the periodic instanton method in the spin-coherent-state path integral, we evaluate the low-lying tunnel splittings between degenerate excited states of neighboring wells. And the low-lying energy level spectrum of m-th excited states are obtained with the help of the Bloch theorem in one-dimensional periodic potential.Comment: 23 pages, final version and accepted by Eur. Phys. J.

    Size-dependent spin-reorientation transition in Nd2Fe14B nanoparticles

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    Nd2Fe14B magnetic nanoparticles have been successfully produced using a surfactant-assisted ball milling technique. The nanoparticles with different size about 6, 20 and 300 nm were obtained by a size-selection process. Spin-reorientation transition temperature of the NdFeB nanoparticles was then determined by measuring the temperature dependence of DC and AC magnetic susceptibility. It was found that the spin-reorientation transition temperature (Tsr) of the nanoparticles is strongly size dependent, i.e., Tsr of the 300 nm particles is lower than that of raw materials and a significant decrease was observed in the 20 nm particles

    Efficient ID-based Signature Without Trusted PKG

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    In this paper, we introduce the exact concept of ID-based signature without trusted Private Key Generator (PKG), which solves the key escrow problem through binding two partially public keys with a same identity. In this scheme, PKG is prevented from forging a legal user’s signature because he only generates the partially private key. Using Gap Diffie-Hellman (GDH) groups, we construct an efficient ID-based signature scheme without trusted PKG, which security relies on the hardness of the Computation Diffie-Hellman Problem (CDHP). More precisely, under the random oracle model, our scheme is proved to be secure against existential forgery on adaptively chosen message and ID attack, which is a natural ID-based version of the standard adaptively chosen message attack, assuming CDHP is intractable. Our scheme not only eliminates the inherent key escrow problem but also has a higher efficiency than the existing schemes

    Naja naja atra

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    Systemic lupus erythematosus (SLE) is an autoimmune disease and effective therapy for this pathology is currently unavailable. We previously reported that oral administration of Naja naja atra venom (NNAV) had anti-inflammatory and immune regulatory actions. We speculated that NNAV may have therapeutic effects in MRL/lpr SLE mice. Twelve-week-old MRL/lpr mice received oral administration of NNAV (20, 40, and 80 μg/kg) or Tripterygium wilfordii polyglycosidium (10 mg/kg) daily for 16 weeks. The effects of NNAV on SLE manifestations, including skin erythema, proteinuria, and anxiety-like behaviors, were assessed with visual inspection and Multistix 8 SG strips and open field test, respectively. The pathology of spleen and kidney was examined with H&E staining. The changes in autoimmune antibodies and cytokines were determined with ELISA kits. The results showed that NNAV protected against the manifestation of SLE, including skin erythema and proteinuria. In addition, although no apparent histological change was found in liver and heart in MRL/lpr SLE mice, NNAV reduced the levels of glutamate pyruvate transaminase and creatine kinase. Furthermore, NNAV increased serum C3 and reduced concentrations of circulating globulin, anti-dsDNA antibody, and inflammatory cytokines IL-6 and TNF-α. NNAV also reduced lymphadenopathy and renal injury. These results suggest that NNAV may have therapeutic values in the treatment of SLE by inhibiting autoimmune responses
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