54,177 research outputs found

    Higher order self-dual models for spin-3 particles in D=2+1D=2+1

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    In D=2+1D=2+1 dimensions, elementary particles of a given helicity can be described by local Lagrangians (parity singlets). By means of a "soldering" procedure two opposite helicities can be joined together and give rise to massive spin-ss particles carrying both helicities ±s\pm s (parity doublets), such Lagrangians can also be used in D=3+1D=3+1 to describe massive spin-ss particles. From this point of view the parity singlets (self-dual models) in D=2+1D=2+1 are the building blocks of real massive elementary particles in D=3+1D=3+1. In the three cases s=1,3/2,2s=1,\, 3/2,\, 2 there are 2s2s self-dual models of order 1,2,,2s1,2, \cdots, 2s in derivatives. In the spin-3 case the 5th order model is missing in the literature. Here we deduce a 5th order spin-3 self-dual model and fill up this gap. It is shown to be ghost free by means of a master action which relates it with the top model of 6th order. We believe that our approach can be generalized to arbitrary integer spin-ss in order to obtain the models of order 2s2s and 2s12s-1. We also comment on the difficulties in relating the 5th order model with their lower order duals

    Natural waters in Amazonia. III. Ammonium molybdate-reactive silica

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    Natural waters of the Amazonian Tertiary formations along the Manaus-Itacoatjara Road were studied with respect to variations in average seasonal and yearly soluble silica content. In general the variations are small and concentrations very low, for all input fractions, i. e., rainfall, stemflow, and throughfall [about 90 percent of the total (470 analyses) lower than 1.0 mg/l]. While 90 percent of total ground water analyses (excluding well IV 3) have soluble silica concentrations lower than 1.5 mg/l, high rain forest stream waters are slightly higher (90 percent of all values lower than 2.0 mg/l). The Rio Negro waters show 90 percent of the total samples analyzed between 2.0 mg/l and 3.0 mg/l soluble silica

    Inert scalar dark matter in an extra dimension inspired model

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    In this paper we analyze a dark matter model inspired by theories with extra dimensions. The dark matter candidate corresponds to the first Kaluza-Klein mode of a real scalar added to the Standard Model. The tower of new particles enriches the calculation of the relic abundance. For large mass splitting, the model converges to the predictions of the inert singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. Moreover, the Kaluza-Klein zero mode can mix with the SM higgs and further constraints can be applied.Comment: 21 pages, 6 figures. We have improved the text and added references. Version published in JCA

    More on dual actions for massive spin-2 particles

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    Here we start from a dual version of Vasiliev's first order action for massless spin-2 particles (linearized first order Einstein-Hilbert) and derive, via Kaluza-Klein dimensional reduction from D+1D+1 to DD dimensions, a set of dual massive spin-2 models. This set includes the massive "BR" model, a spin-2 analogue of the spin-1 Cremmer-Scherk model. In our approach the linearized Riemann curvature emerges from a solution of a functional constraint. In D=2+1D=2+1 the BR model can be written as a linearized version of a new bimetric model for massive gravitons. We also have a new massive spin-2 model, in arbitrary dimensions, invariant under linearized diffeomorphisms. It is given in terms of a non symmetric rank-2 tensor and a mixed symmetry tensor.Comment: 18 pages, 0 figure
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