16106369
The Euler–Lagrange Cohomology and General Volume-Preserving Systems
We briefly introduce the concept of Euler–Lagrange cohomology groups on a symplectic manifold (ℳ2n, ω) and systematically present the general form of volume-preserving equations on the manifold from the cohomological point of view. It is shown that for every volume-preserving flow generated by these equations there is an important two-form that plays the analog role with the Hamiltonian in the Hamilton mechanics. In addition, the ordinary canonical equations with Hamiltonian H are included as a special case with the two-form . The other volume preserving systems on (ℳ2n, ω) are studied. The relations between our approach and Feng–Shang's volume-preserving systems as well as the Nambu mechanics are also explored.
115169240
The principle of relativity and the special relativity triple
Abstract Based on the principle of relativity and the postulate on universal invariant constants ( c , l ) as well as Einstein's isotropy conditions, three kinds of special relativity form a triple with a common Lorentz group as isotropy group under full Umov–Weyl–Fock–Lorentz transformations among inertial motions.
122921314
Smooth U(1) Gauge Potentials on the de Sitter Spacetime
Using the methods of Lie groups and Lie algebras, we solved U(1) gauge potentials on the de Sitter background. Resulted gauge potentials are smooth on the whole spacetime, satisfying the Lorentz gauge condition. It is shown that electromagnetic fields on the de Sitter background could not be source free.
119056121
A study of antineutrino spectra from spent nuclear fuel at Daya Bay
The Daya Bay Reactor Antineutrino Experiment is designed to determine the as yet unknown neutrino mixing angle, θ13, by measuring the disappearance of electron antineutrinos from several nuclear reactor cores. The projected sensitivity in sin2 (2θ13) of better than 0.01 at a 90% CL should be achieved after three years of data-taking. Antineutrinos emitted from spent nuclear fuel (SNF) distort the soft part of the energy spectrum. In this article, a calculation of the antineutrino spectra from the long-life isotopes in SNF is performed. A non-equilibrium generation of long half-life isotopes during the running time of the reactor is also analyzed. Finally, we show that the antineutrino event rate contribution from SNF, which has been stored in the SNF pool for several years, may be non-negligible.
118403311
Geometry and optics calibration of WFCTA prototype telescopes using star light
The Large High Altitude Air Shower Observatory project is proposed to study high energy gamma ray astronomy ( 40 GeV-1 PeV ) and cosmic ray physics ( 20 TeV-1 EeV ). The wide field of view Cherenkov telescope array, as a component of the LHAASO project, will be used to study energy spectrum and compositions of cosmic ray by measuring the total Cherenkov light generated by air showers and shower maximum depth. Two prototype telescopes have been in operation since 2008. The pointing accuracy of each telescope is crucial to the direction reconstruction of the primary particles. On the other hand the primary energy reconstruction relies on the shape of the Cherenkov image on the camera and the unrecorded photons due to the imperfect connections between photomultiplier tubes. UV bright stars are used as point-like objects to calibrate the pointing and to study the optical properties of the camera, the spot size and the fractions of unrecorded photons in the insensitive areas of the camera.
16242259
Conformal Triality of de Sitter, Minkowski and Anti-de Sitter Spaces
We describe how conformal Minkowski, dS- and AdS-spaces can be united into a single submanifold [N] of RP^5. It is the set of generators of the null cone in M^{2,4}. Conformal transformations on the Mink-, dS- and AdS-spaces are induced by O(2,4) linear transformations on M^{2,4}. We also describe how Weyl transformations and conformal transformations can be resulted in on [N]. In such a picture we give a description of how the conformal Mink-, dS- and AdS-spaces as well as [N] are mapped from one to another by conformal maps. This implies that a CFT in one space can be translated into a CFT in another. As a consequence, the AdS/CFT-correspondence should be extended.
118116548
GeV excess in the Milky Way: Depending on Diffuse Galactic gamma ray Emission template?
University of Chinese Academy of Sciences, Yuquan Road 19, Beijing, 100049, China.(Dated: June 27, 2014)Several groups have analyzed the publicly-available Fermi-LAT data and reported a spatiallyextended gamma rays excess of around 1−3 GeV from the region surrounding the Galactic Centerthat might originate from annihilation of dark matter particles with a rest mass m