38 research outputs found

    Minimization of the scalar Higgs potential in the Finite Supersymmetric Grand Unified Theory

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    Exact mathematical solution of the minimization conditions of scalar the Higgs potential of the Finite Supersymmetric Grand Unification Theory is proposed and extremal field configurations are found. Types of extrema are investigated and masses of the new Higgs particles arisen after electroweak symmetry breaking are derived analytically. The conditions for existing of physically acceptable minimum are given. As it appears, this minimum is simple generalization of the analogous solution in the Minimal Supersymmetric Standard Model. Phenomenological consequences are discussed briefly.Comment: Latex, 18 pages, 1 postscript figure (included at the end

    An approach to solve Slavnov-Taylor identity in D4 N=1 supergravity

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    We consider a particular solution to Slavnov-Taylor identity in four-dimensional supergravity. The consideration is performed for pure supergravity, no matter superfields are included. The solution is obtained by inserting dressing functions into ghost part of the classical action for supergravity.As a consequence, physical part of the effective action is local invariant with respect to diffeomorphism and structure groups of transformation for dressed effective superfields of vielbein and spin connection.Comment: 6 pages, minor changes, to appear in Mod.Phys.Lett.

    QCD effective action with dressing functions - consistency checks in the perturbative regime

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    In a previous paper, we presented solution to the Slavnov--Taylor identity for the QCD effective action, and argued that the action terms containing (anti)ghost fields are unique. These terms have the same form as those in the classical action, but the gluon and (anti)ghost effective fields are convoluted with gluon and ghost dressing functions G_A and G_c, the latter containing perturbative and nonperturbative effects (but not including the soliton-like vacuum effects). In the present work we show how the perturbative QCD (pQCD) can be incorporated into the framework of this action, and we present explicit one-loop pQCD expressions for G_A and G_c. We then go on to check the consistency of the obtained results by considering an antighost Dyson--Schwinger equation (DSE). By solving the relations that result from the Legendre transformation leading to the effective action, we obtain the effective fields as power expansions of sources. We check explicitly that the aforementioned one-loop functions G_A and G_c fulfil the antighost DSE at the linear source level. We further explicitly check that these one-loop G_A and G_c have the regularization-scale and momentum dependence consistent with the antighost DSE at the quadratic source level. These checks suggest that the the effective action with dressing functions represents a consistent framework for treating QCD, at least at the one-loop level.Comment: 17 pages, revtex4; dimensional regularization used instead of Pauli-Villars, the check of identity in the linear-in-sources Dyson-Schwinger equation now includes the finite part; conclusions unchanged; to appear in Phys.Rev.

    Difficulties of an Infrared Extension of Differential Renormalization

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    We investigate the possibility of generalizing differential renormalization of D.Z.Freedman, K.Johnson and J.I.Latorre in an invariant fashion to theories with infrared divergencies via an infrared R~\tilde{R} operation. Two-dimensional σ\sigma models and the four-dimensional ϕ4\phi^4 theory diagrams with exceptional momenta are used as examples, while dimensional renormalization serves as a test scheme for comparison. We write the basic differential identities of the method simultaneously in co-ordinate and momentum space, introducing two scales which remove ultraviolet and infrared singularities. The consistent set of Fourier-transformation formulae is derived. However, the values for tadpole-type Feynman integrals in higher orders of perturbation theory prove to be ambiguous, depending on the order of evaluation of the subgraphs. In two dimensions, even earlier than this ambiguity manifests itself, renormalization-group calculations based on infrared extension of differential renormalization lead to incorrect results. We conclude that the extended differential renormalization procedure does not perform the infrared R~\tilde{R} operation in a self-consistent way, as the original recipe does the ultraviolet RR operation.Comment: (minor changes have been made to make clear that no infrared problems occur in the original ultraviolet procedure of [1]; subsection 2.1 has been added to outline the ideas a simple example), 26 pages, LaTeX, JINR preprint E2-92-538, Dubna (Dec.1992

    Towards the two-loop Lcc vertex in Landau gauge

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    We are interested in the structure of the Lcc vertex in the Yang-Mills theory, where c is the ghost field and L the corresponding BRST auxiliary field. This vertex can give us information on other vertices, and the possible conformal structure of the theory should be reflected in the structure of this vertex. There are five two-loop contributions to the Lcc vertex in the Yang-Mills theory. We present here calculation of the first of the five contributions. The calculation has been performed in the position space. One main feature of the result is that it does not depend on any scale, ultraviolet or infrared. The result is expressed in terms of logarithms and Davydychev integral J(1,1,1) that are functions of the ratios of the intervals between points of effective fields in the position space. To perform the calculation we apply Gegenbauer polynomial technique and uniqueness method.Comment: 27 pp, 2 figures, Latex2e, revised version, to appear in IJMPA, references added, comments on nonsupersymmetric case adde

    Further results for the two-loop Lcc vertex in the Landau gauge

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    In the previous paper hep-th/0604112 we calculated the first of the five planar two-loop diagrams for the Lcc vertex of the general non-Abelian Yang-Mills theory, the vertex which allows us in principle to obtain all other vertices via the Slavnov-Taylor identity. The integrand of this first diagram has a simple Lorentz structure. In this letter we present the result for the second diagram, whose integrand has a complicated Lorentz structure. The calculation is performed in the D-dimensional Euclidean position space. We initially perform one of the two integrations in the position space and then reduce the Lorentz structure to D-dimensional scalar single integrals. Some of the latter are then calculated by the uniqueness method, others by the Gegenbauer polynomial technique. The result is independent of the ultraviolet and the infrared scale. It is expressed in terms of the squares of spacetime intervals between points of the effective fields in the position space -- it includes simple powers of these intervals, as well as logarithms and polylogarithms thereof, with some of the latter appearing within the Davydychev integral J(1,1,1). Concerning the rest of diagrams, we present the result for the contributions correponding to third, fourth and fifth diagrams without giving the details of calculation. The full result for the Lcc correlator of the effective action at the planar two-loop level is written explicitly for maximally supersymmetric Yang-Mills theory.Comment: 29 pages, 1 figure, minor changes; three references added, one new paragraph in Introduction added, Note Added is extended; to appear in JHE

    Comment on the ``ξ\theta-term renormalization in the (2+1)-dimensional CPN−1CP^{N-1} model with ξ\theta term''

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    It is found that the recently published first coefficient of nonzero ÎČ\beta-function for the Chern-Simons term in the 1/N1/N expansion of the CPN−1CP^{N-1} model is untrue numerically. The correct result is given. The main conclusions of Park's paper are not changed.Comment: 3 pages, LATE

    An approach to solve Slavnov-Taylor identities in nonsupersymmetric non-Abelian gauge theories

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    We present a way to solve Slavnov--Taylor identities in a general nonsupersymmetric theory. The solution can be parametrized by a limited number of functions of spacetime coordinates, so that all the effective fields are dressed by these functions via integral convolution. The solution restricts the ghost part of the effective action and gives predictions for the physical part of the effective action.Comment: revised version, section 3 is enlarged, 24 pages, Latex2e, no figures, version accepted by Phys. Rev.
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