Spin and mass content of linearized Poincaré gauge theories

A unified gauge theory of massless and massive spin-2 fields is of considerable current interest. The Poincaré gauge theories with quadratic Lagrangian are linearized, and the conditions on the parameters are found which will lead to viable linear theories with massive gauge particles. As well as the 2⁺ massless gravitons coming from the translational gauge potential, the rotational gauge potentials, in the linearized limit, give rise to 2⁺ and 2⁻ particles of equal mass, as well as a massive pseudoscalar.     

Gauge Model with Massive Gravitons

Gauge theory of gravity is formulated based on principle of local gauge invariance. Because the model hasstrict local gravitational gauge symmetry, and gauge theory of gravity is a perturbatively renormalizable quantum model.However, in the original model, all gauge gravitons are massless. We want to ask whether there exist massive gravitonsin Nature. In this paper, we will propose a gauge model with massive gravitons. The mass term of gravitational gaugefield is introduced into the theory without violating the strict local gravitational gauge symmetry. Massive gravitons canbe considered to be possible origin of dark energy and dark matter in the Universe.     

Critical gravity in four dimensions

We study four-dimensional gravity theories that are rendered renormalizable by the inclusion of curvature-squared terms to the usual Einstein action with a cosmological constant. By choosing the parameters appropriately, the massive scalar mode can be eliminated and the massive spin-2 mode can become massless. This "critical" theory may be viewed as a four-dimensional analogue of chiral topologically massive gravity, or of critical "new massive gravity" with a cosmological constant, in three dimensions. We find that the on-shell energy for the remaining massless gravitons vanishes. There are also logarithmic spin-2 modes, which have positive energy. The mass and entropy of standard Schwarzschild-type black holes vanish. The critical theory might provide a consistent toy model for quantum gravity in four dimensions.     

Cosmic Acceleration in a Model of Interacting Massive Gravitons Dark Energy

We propose an alternative understanding of gravity, resulting from the extension of N. Wu’s gauge theory of gravity with massive gravitons, which are minimally coupled to massless gravitons. Based on this, we derive the equations of state for massive gravitons. We study the dynamics of these massive gravitons in a flat, homogeneous and isotropic Friedmann-Robertson-Walker (FRW) universe. We calculate the critical points of the massive graviton dark energy interacting with background perfect fluid. These calculations may have crucial implications for the massive gravitons and dark energy theories. They could, therefore, have important repercussions for current cosmological problems.     

Interaction Between Massive and Massless Gravitons by Perturbing Topological Field Theory

We test the Wu gauge theory of gravity with massive gravitons in the perturbing topological field theory framework.We show that the computation of the correlation function between massive and massless gravitons is reported up to 4-loop and appears to be unaffected by radiative correction.This result ensures the stability of the linking number between massive and massless gravitons with respect to the local perturbation,a result with potential wider applications in cosmology.     

The phase structure of Einstein–Cartan theory

In the Einstein–Cartan theory of torsion-free gravity coupling to massless fermions, the four-fermion interaction is induced and its strength is a function of the gravitational and gauge couplings, as well as the Immirzi parameter. We study the dynamics of the four-fermion interaction to determine whether effective bilinear terms of massive fermion fields are generated. Calculating one-particle-irreducible two-point functions of fermion fields, we identify three different phases and two critical points for phase transitions characterized by the strength of four-fermion interaction: (1) chiral symmetric phase for massive fermions in strong coupling regime; (2) chiral symmetric broken phase for massive fermions in intermediate coupling regime; (3) chiral symmetric phase for massless fermions in weak coupling regime. We discuss the scaling-invariant region for an effective theory of massive fermions coupled to torsion-free gravity in the low-energy limit.     

All spin-2 cubic vertices with two derivatives

In this paper we provide a complete list of spin-2 cubic interaction vertices with two derivatives. We work in (anti) de Sitter space with dimension d?4$d?4$ and arbitrary value of cosmological constante and use simple metric formalism without any auxiliary or Stueckelberg fields. We separately consider cases with one, two and three different spin-2 fields entering the vertex where each field may be massive, massless or partially massless one. The connection of our results with massive (bi)gravity theories is also briefly discussed.     

Cartan's contortion as a system of spin-2 and spin-0 fields

In several previous papers the author proposed to consider Cartan's contortion as a gauge field of Lorentz-group mediated by a massless spin-2 fields twin. In this article it is shown that these fields may be accompanied by a further pair of massive or massless spin-0 fields. Unfortunately, the study of the interaction of contortion with a Proca field shows that there is no reasonable macroscopic source generating the contortion. This defect is essential; the contortion mediated by standard fields can hardly exist in nature.     

Gravitational waves and massive tensor particles in thef-g theory of gravity

Starting from the generally covariant version of the Pauli-Fierz mass term, it is stressed that the tensor fields representing spin-2 particles, eigenstates of strong and gravitational interactions, are linear combinations of one massive and one massless state. This implies that any hadronic reaction, in which massive tensor particles are produced, can be regarded, at least in principle, also as an effective source of gravitons which may become very important in the early stages of the universe; conversely, any process in which gravitational radiation of sufficiently high energy is emitted, should be a source of strongly interacting tensor particles which decay into photons and neutrinos. These two effects could be used for producing and detecting gravitational waves.This essay was awarded an honorable mention (1985) by the Gravity Research Foundation—Ed.     

Spontaneous lorentz breaking and massive gravity

Theories with an extra spin-two field coupled to gravity admit a massive phase with broken Lorentz symmetry. While the equivalence principle is respected, the Newtonian potentials are in general modified, but they may be protected by a scale symmetry of the coupling term. The gravitational waves phenomenology is quite rich: two gravitons, one massive and one massless, oscillate and propagate with distinct velocities, different from the speed of light. A time of flight difference between gravitons and photons from a common source would provide a clear signal of this theory.     

Gauge theory of massless spin-(3/2) field in de Sitter space-time

On several levels of theoretical physics, especially particle physics and early universe cosmology, de Sitter space-time has become an attractive possibility. The principle of local gauge invariance governs all known fundamental interactions of elementary particles, from electromagnetism and weak interactions to strong interactions and gravity. This paper presents a procedure for defining the gauge-covariant derivative and gauge invariant Lagrangian density in de Sitter ambient space-time formalism. The gauge invariant field equation is then explicitly calculated in detail for a massless spin-(3/2) gauge field.     

Spin-3 topologically massive gravity

In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS₃ vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W₃ algebra and central charge cR=3l/G.     

Cubic interaction vertex of higher-spin fields with external electromagnetic field

We fulfill the detailed analysis of coupling the charged bosonic higher-spin fields to external constant electromagnetic field in first order in external field strength. Cubic interaction vertex of arbitrary massive and massless bosonic higher-spin fields with external field is found. Construction is based on deformation of free Lagrangian and free gauge transformations by terms linear in electromagnetic field strength. In massive case a formulation with Stueckelberg fields is used. We begin with the most general form of deformations for Lagrangian and gauge transformations, admissible by Lorentz covariance and gauge invariance and containing some number of arbitrary coefficients, and require the gauge invariance of the deformed theory in first order in strength. It yields the equations for the coefficients which are exactly solved. As a result, the complete interacting Lagrangian of arbitrary bosonic higher-spin fields with constant electromagnetic field in first order in electromagnetic strength is obtained. Causality of massive spin-2 and spin-3 fields propagation in the corresponding electromagnetic background is proved.     

HELAS and MadGraph/MadEvent with spin-2 particles

Fortran subroutines to calculate helicity amplitudes with massive spin-2 particles (massive gravitons), which couple to the standard model particles via the energy momentum tensor, are added to the HELAS (HELicity Amplitude Subroutines) library. They are coded in such a way that arbitrary scattering amplitudes with one graviton production and its decays can be generated automatically by MadGraph and MadEvent, after slight modifications. All the codes have been tested carefully by making use of the invariance of the helicity amplitudes under the gauge and general coordinate transformations.     

Tree level gravity—scalar matter interactions in analogy with Fermi theory of weak interactions using only a massive vector field

In this paper we work in perturbative quantum gravity coupled to scalar matter at tree level and we introduce a new effective model in analogy with the Fermi theory of weak interaction and in relation with a previous work where we have studied only the gravity and its self-interaction. This is an extension of the I.T.B. model (Intermediate-Tensor-Boson) for gravity also to gravitationally interacting scalar matter. We show that in a particular gauge the infinite series of interactions containing n gravitons and two scalars could be rewritten in terms of only two Lagrangians containing a massive field, the graviton and, obviously, the scalar field. Using the S-matrix we obtain that the low energy limit of the amplitude reproduces the local Lagrangian for the scalar coupled to gravity.     

SU(2) × SU(2) Electroweak Theory II: Chiral and Vector Fields on the Physical Vacuum

In this letter a discussion is offered on how symmetry breaking of a theory with twisted bundle of two chiral SU(2) bundles leads to a set of gauge potentials from each group on the physical vacuum that are vector and chiral. The result is that symmetry breaking of this theory leads to massive A ³ transverse modes of the 3-photon along with electromagnetic photons plus the massive neutral and charged weakly interacting bosons. The electromagnetic sector is demonstrated to be a massless vector field and the remainder is a broken chiral field theory.     

Gravitational divergences of the electromagnetic interactions of massive vector particles

In a search for the explanation of the finite quantum gravity corrections to anomalous moments we examined a spontaneous broken O(3) model with Yang-Mills particles and Higgs scalars coupled to gravitons. We found several new cancellations which prove that the coupling of all these particles together does not produce new counterterms apart from these which are known to exist in the subsystems and the cosmological term. The finiteness of the anomalous magnetic moment of a massive spin-1 particle is necessary for this to be valid. The finiteness of the anomalous quadrupole moment is a consequence of a known cancellation in the Einstein-Yang-Mills system. We also checked infrared finiteness and showed how to treat logarithmically divergent massless integrals in dimensional regularization.     

Charged tensor matter fields and Lorentz symmetry violation via spontaneous symmetry breaking

We consider a model with a charged vector field along with a Cremmer-Scherk-Kalb-Ramond (CSKR) matter field coupled to a U(1) gauge potential. We obtain a natural Lorentz symmetry violation due to the local U(1) spontaneous symmetry breaking mechanism triggered by the imaginary part of the vector matter. The choice of the unitary gauge leads to the decoupling of the gauge-KR sector from the Higgs-KR sector. The excitation spectrum is carefully analyzed and the physical modes are identified. We propose an identification of the neutral massive spin-1 Higgs-like field with the massive Z boson of the so-called mirror matter models.Received: 30 October 2003, Revised: 16 March 2004, Published online: 23 June 2004     

Topologically massive gauge theories

Gauge vector and gravity models are studied in three-dimensional space-time, where novel, gauge invariant, P and T odd terms of topological origin give rise to masses for the gauge fields. In the vector case, the massless Maxwell excitation, which is spinless, becomes massive with spin 1. When interacting with fermions, the quantum theory is infrared and ultraviolet finite in perturbation theory. For non-Abelian models, topological considerations lead to a quantization condition on the dimensionless coupling constant-mass ratio. Ordinary Einstein gravity is trivial, but when augmented by our mass term, it acquires a propagating, massive, spin 2 mode. This theory is ghost-free and causal, although of third-derivative order. Quantum calculations are presented in both the Abelian and non-Abelian vector models, to exhibit some of the delicate aspects of infrared behavior, and regularization dependence.     

Mass spectrum of the M4×SD solution in Euler invariant type higher derivative gravity

The mass spectrum is computed in Euler invariant type higher derivative gravity theory in the case that the space-time is dimensionally reduced to the four-dimensional Minkowski space × D-dimensional sphere. It is shown at the linearized level that after the compactification there appear massless gravitons, massive spin-two particles, massless vectors and one massive scalar mode. All the vectors are massless and the masses of massive spin-two particles are proportional to the S^D eigenvalues of the laplacian. Classical stability is shown to depend only on three parameters.