6,000 research outputs found

    Two loops calculation in chiral perturbation theory and the unitarization program of current algebra

    Get PDF
    In this paper we compare two loop Chiral Perturbation Theory (ChPT) calculation of pion-pion scattering with the unitarity second order correction to the current algebra soft-pion theorem. It is shown that both methods lead to the same analytic structure for the scattering amplitude.Comment: 13 pages, Revtex 3.0, no figures, submitted to Phys. Lett.

    Symmetry breaking patterns of the 3-3-1 model at finite temperature

    Get PDF
    We consider the minimal version of an extension of the standard electroweak model based on the SU(3)cĂ—SU(3)LĂ—U(1)XSU(3)_c \times SU(3)_L \times U(1)_X gauge symmetry (the 3-3-1 model). We analyze the most general potential constructed from three scalars in the triplet representation of SU(3)LSU(3)_L, whose neutral components develop nonzero vacuum expectation values, giving mass for all the model's massive particles. {}For different choices of parameters, we obtain the particle spectrum for the two symmetry breaking scales: one where the SU(3)LĂ—U(1)XSU(3)_L \times U(1)_X group is broken down to SU(2)LĂ—U(1)YSU(2)_L\times U(1)_Y and a lower scale similar to the standard model one. Within the considerations used, we show that the model encodes two first-order phase transitions, respecting the pattern of symmetry restoration. The last transition, corresponding to the standard electroweak one, is found to be very weak first-order, most likely turning second-order or a crossover in practice. However, the first transition in this model can be strongly first-order, which might happen at a temperature not too high above the second one. We determine the respective critical temperatures for symmetry restoration for the model.Comment: 13 pages, 8 figures. Minor changes to match published versio

    Unitarized pion-nucleon scattering amplitude from inverse amplitude method

    Full text link
    In a recent work on low energy pion-nucleon scattering, instead of using chiral perturbation theory (ChPT) amplitude, we started from a pion-nucleon {\it soft-pion} result and used elastic unitarity directly as a dynamical constraint to construct first-order unitarity corrected amplitudes. The resulting amplitudes are crossing symmetric but, as the ChPT ones, satisfy only approximate unitarity relation. In the present work, we reconsider our approach and we apply the inverse amplitude method (IAM) in order to access the energy resonance region. We present the resulting S- and P-wave phase shifts that are shown to be in qualitative agreement with experimental data.Comment: 6 pages, 3 figure

    Stationary Black Holes in a Generalized Three-Dimensional Theory of Gravity

    Get PDF
    We consider a generalized three-dimensional theory of gravity which is specified by two fields, the graviton and the dilaton, and one parameter. This theory contains, as particular cases, three-dimensional General Relativity and three-dimensional String Theory. Stationary black hole solutions are generated from the static ones using a simple coordinate transformation. The stationary black holes solutions thus obtained are locally equivalent to the corresponding static ones, but globally distinct. The mass and angular momentum of the stationary black hole solutions are computed using an extension of the Regge and Teitelboim formalism. The causal structure of the black holes is described.Comment: 12 pages, Late

    Explicit Soliton for the Laplacian Co-Flow on a Solvmanifold

    Full text link
    We apply the general Ansatz in geometric flows on homogeneous spaces proposed by Jorge Lauret for the Laplacian co-flow of invariant G2G_2-structures on a Lie group, finding an explicit soliton on a particular almost Abelian 77-manifold.Comment: Minor corrections, proof's Lemma 4.1 modified. To appear in the S\~ao Paulo Journal of mathematical scienc

    Analytical r-mode solution with gravitational radiation reaction force

    Full text link
    We present and discuss the analytical r-mode solution to the linearized hydrodynamic equations of a slowly rotating, Newtonian, barotropic, non-magnetized, perfect-fluid star in which the gravitational radiation reaction force is present.Comment: 3 pages, in Proceedings of the 5th International Workshop "New Worlds in Astroparticle Physics", Faro, Portugal, 8-10 January 200
    • …
    corecore