Antisymmetric Tensor Field Research Articles

Reactions with pions and vector mesons in the sector of odd intrinsic parity

In chiral perturbation theory, the leading-order contribution to reactions with pions in the sector of odd intrinsic parity is defined by the Wess-Zumino-Witten structure. This structure is supplemented by a simple vector-meson Lagrangian where the vector mesons are described by antisymmetric tensor fields. With the rho-omega-pion coupling as the only parameter in the sector of odd intrinsic parity, i.e. without additional contact terms, one can achieve a proper description of the pion transition form factor and the three-pion production in electron-positron collisions.

Antisymmetric tensor Z p gauge symmetries in field theory and string theory

Abstract We consider discrete gauge symmetries in D dimensions arising as remnants of broken continuous gauge symmetries carried by general antisymmetric tensor fields, rather than by standard 1-forms. The lagrangian for such a general Z p gauge theory can be described in terms of a r-form gauge field made massive by a (r − 1)-form, or other dual realizations, that we also discuss. The theory contains charged topological defects of different dimensionalities, generalizing the familiar charged particles and strings in D = 4. We describe realizations in string theory compactifications with torsion cycles, or with background field strength fluxes. We also provide examples of non-abelian discrete groups, for which the group elements are associated with charged objects of different dimensionality.

Reactions with pions and vector mesons in the sector of odd intrinsic parity

The Wess-Zumino-Witten structure is supplemented by a simple vector-meson Lagrangian where the vector mesons are described by antisymmetric tensor fields. With the \rho-\omega-\pi{} coupling as the only parameter in the sector of odd intrinsic parity, i.e. without additional contact terms, one can achieve a proper description of the decay of an \omega-meson into three pions, the single- and double-virtual pion transition form factor and the three-pion production in electron-positron collisions.

Violation of CPT Invariance in the Early Universe and Leptogenesis/Baryogenesis

In this talk, I review some plausible scenarios entailing violation of CPT symmetry in the early Universe, due to space-time backgrounds which do not respect some of the assumptions for the validity of the CPT theorem (here considered will be Lorentz invariance and/or Unitarity). The key point in all these models is that the background induces different populations of fermions as compared to antifermions, and hence CPT Violation (CPTV), already in thermal equilibrium. Such populations may freeze out at various conditions depending on the details of the underlying microscopic model, thereby leading to leptogenesis and baryogenesis. Among the considered scenarios is a stringy one, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. We also discuss briefly (Lorentz Violating) CPTV models that go beyond the local effective lagrangian framework, such as a stochastic Finsler metric and D-particle foam. In the latter, the CPTV is induced by the interactions of stringy matter with populations of stochastically fluctuating point-like space-time defects (D-particles) that can be encountered in string/brane Cosmologies. The preferential rôle of neutrinos is singled out in this latter scenario as a consequence of gauge symmetry (charge) conservation.

Environmental CPT violation in an expanding Universe in string theory

We consider a model of an expanding Universe in string theory that yields ‘environmental’ CPT violation for fermions, in the sense of different dispersion relations for fermions and antifermions. These are induced by a cosmological background with constant torsion provided by the Kalb–Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. This effect induces different densities of neutrinos and antineutrinos while in chemical equilibrium, offering new scenarios for leptogenesis and baryogenesis even in the absence of CP violation.

CPT-violating leptogenesis induced by gravitational backgrounds

We explore leptogenesis induced by the propagation of neutrinos in non-trivial gravitational backgrounds that may characterise the Early Universe epochs of various theories, including string theory. The key point in all these models is that the background induces different populations of fermions as compared to antifermions, and hence CPT Violation (CPTV), already in thermal equilibrium. Depending on the model, then, such populations may freeze out at various conditions leading to leptogenesis and baryogenesis. Among the considered scenarios, is a stringy one, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. We also discuss CPTV models that go beyond the local effective lagrangian framework, such as a stochastic (Lorentz Violating) Finsler metric and D-particle foam, where the CPTV is due to populations of stochastically fluctuating point-like space-time defects that can be encountered in string/brane theory (D0 branes).

A Lorentz invariant doubled world-sheet theory

We propose a Lorentz invariant version of Tseytlin's doubled worldsheet theory that makes T-duality covariance of the string manifest. This theory can be derived as a gauge fixed version of Buscher's gauging procedure, in which the left-over gauge field component acts as a Lagrange multiplier. This description can naturally account for fractional linear O(D,D) transformations of the metric and b-field. It is capable of describing non-geometric backgrounds; geometric and non-geometric fluxes are encoded in the doubled anti-symmetric tensor field strength.

Gauge invariant and gauge fixed actions for various higher-spin fields from string field theory

We propose a systematic procedure for extracting gauge invariant and gauge fixed actions for various higher-spin gauge field theories from covariant bosonic open string field theory. By identifying minimal gauge invariant part for the original free string field theory action, we explicitly construct a class of covariantly gauge fixed actions with BRST and anti-BRST invariance. By expanding the actions with respect to the level N of string states, the actions for various massive fields including higher-spin fields are systematically obtained. As illustrating examples, we explicitly investigate the level N⩽3 part and obtain the consistent actions for massive graviton field, massive 3rd rank symmetric tensor field, or anti-symmetric field. We also investigate the tensionless limit of the actions and explicitly derive the gauge invariant and gauge fixed actions for general rank n symmetric and anti-symmetric tensor fields.

NONTRIVIAL GHOSTS AND SECOND-CLASS CONSTRAINTS

In a model in which a vector gauge field [Formula: see text] is coupled to an antisymmetric tensor field [Formula: see text] possessing a pseudoscalar mass, it has been shown that all physical degrees of freedom reside in the vector field. Upon quantizing this model using the Faddeev–Popov procedure, explicit calculation of the two-point functions 〈ϕϕ〉 and 〈Wϕ〉 at one-loop order seems to have yielded the puzzling result that the effective action generated by radiative effects has more physical degrees of freedom than the original classical action. In this paper we point out that this is not in fact a real effect, but rather appears to be a consequence of having ignored a "ghost" field arising from the contribution to the measure in the path integral arising from the presence of nontrivial second-class constraints. These ghost fields couple to the fields [Formula: see text] and [Formula: see text], which makes them distinct from other models involving ghosts arising from second-class constraints (such as massive Yang–Mills (YM) models) that have been considered, as in these other models such ghosts decouple. As an alternative to dealing with second-class constraints, we consider introducing a "Stueckelberg field" to eliminate second-class constraints in favor of first-class constraints and examine if it is possible to then use the Faddeev–Popov quantization procedure. In the Proca model, introduction of the Stueckelberg vector is equivalent to the Batalin–Fradkin–Tyutin (BFT) approach to converting second-class constraints to being first-class through the introduction of new variables. However, introduction of a Stueckelberg vector is not equivalent to the BFT approach for the vector–tensor model. In an appendix, the BFT procedure is applied to the pure tensor model and a novel gauge invariance is found. In addition, we also consider extending the Hamiltonian so that half of the second-class constraints become first-class and the other half become associated gauge conditions. We also find for this tensor-vector theory that when converting the phase space path integral to the configuration space path integral, a nontrivial contribution to the measure arises that is not manifestly covariant and which is not simply due to the presence of second-class constraints.

Gravitating tensor monopole in a Lorentz-violating field theory

We present a solution of the coupled Einstein and rank-two antisymmetric tensor field equations where Lorentz symmetry is spontaneously broken, and we discuss its observational signatures. Especially, the deflection angles have important qualitative differences between tensor and scalar monopoles. If a monopole were to be detected, it would be discriminated whether or not to correspond to a tensor one. This phenomenon might open up new directions in the search of Lorentz violation with future astrophysical observations.

All the fundamental massless bosonic fields in superstring theory

AbstractA systematic analysis of all the massless bosonic fields in superstring theory is carried out. Emphasis is put on the derivation of their propagators, their polarization aspects and the investigation of their underlying constraints as well as their number of degrees of freedom. The treatment is given in the presence of external sources, in the celebrated Coulomb gauge, ensuring the positivity of the formalism ‐ a result which is also established in the process. The challenge here is the investigation involved in the self‐dual fourth rank anti‐symmetric tensor field. No constraints are imposed on the external sources so that their components may be varied independently, thus the complete expressions of the propagators may be obtained. As emphasized in our earlier work, the latter condition is an important one in dynamical theories with constraints giving rise to modifications as Faddeev‐Popov factors. The analysis is carried out in 10 dimensions, not only because of the consistency requirement by the superstrings, but also in order to take into account of the self‐duality character of the fourth rank anti‐symmetric tensor field as spelled out in the paper.

A class of models with spontaneous compactification of the Freund-Rubin type and a nontrivial solution for the vector field

A theory of interacting gravity, vector, and antisymmetric third-rank tensor fields with self-consistent spontaneous compactification solutions of the Freund-Rubin type in seven-dimensional space-time is considered. A class of models is studied, which allow the same type of compactification and possess nontrivial solutions for the vector field. A subclass of the models is separated in which the four-dimensional Lorentz invariance is either unbroken or weakly broken.

Kalb–Ramond excitations in a thick-brane scenario with dilaton

We compute the full spectrum and eigenstates of the Kalb-Ramond field in a warped non-compact Randall-Sundrum -type five-dimensional spacetime in which the ordinary four-dimensional braneworld is represented by a sine-Gordon soliton. This 3-brane solution is fully consistent with both the warped gravitational field and bulk dilaton configurations. In such a background we embed a bulk antisymmetric tensor field and obtain, after reduction, an infinite tower of normalizable Kaluza-Klein massive components along with a zero-mode. The low lying mass eigenstates of the Kalb-Ramond field may be related to the axion pseudoscalar. This yields phenomenological implications on the space of parameters, particularly on the dilaton coupling constant. Both analytical and numerical results are given.

The $ \mathcal{N} = 4 $ effective action of type IIA supergravity compactified on SU(2)-structure manifolds

We study compactifications of type IIA supergravity on six-dimensional manifolds with SU(2) structure and compute the low-energy effective action in terms of the non-trivial intrinsic torsion. The consistency with gauged N=4 supergravity is established and the gauge group is determined. Depending on the structure of the intrinsic torsion, antisymmetric tensor fields can become massive.

Cosmology inp-brane systems

We present time-dependent solutions in the higher-dimensional gravity which are related to supergravity in the particular cases. Here, we consider p-branes with a cosmological constant and the intersections of two and more branes. The dynamical description of p-branes can be naturally obtained as the extension of static solutions. In the presence of a cosmological constant, we find accelerating solutions if the dilaton is not dynamical. In the case of intersecting branes, the field equations normally indicate that time-dependent solutions in supergravity can be found if only one harmonic function in the metric depends on time. However, if the special relation between dilaton couplings to antisymmetric tensor field strengths is satisfied, one can find a new class of solutions where all harmonic functions depend on time. We then apply our new solutions to study cosmology, with and without performing compactifications.

Antisymmetric tensor fields in a generalized Randall–Sundrum scenario

Bulk antisymmetric tensor fields of different ranks have been studied in the context of a generalized Randall–Sundrum model with a non-vanishing induced cosmological constant on the visible brane. It is shown that instead of the usual exponential suppression of the couplings of the zero modes of these bulk fields with the brane fermions in the original Randall–Sundrum model, here the couplings are proportional to the brane cosmological constant. Thus in an era of large cosmological constant these fields have significant role in physical phenomena because of their enhanced couplings with the visible brane fermions.

LOW ENERGY ACTION OF "COVARIANT" SUPERSTRING FIELD THEORY IN THE NS–NS pp-WAVE BACKGROUND

Exact construction of superstring field theory in some background fields is very important. We construct the low energy NS–NS sector of superstring field action in the pp-wave background with the flux of NS–NS antisymmetric tensor field (NS–NS pp-wave) without gauge fixing up to the second-order where the action is worldsheet BRST invariant. Here we use the word "covariant" in a invariant theory for a symmetric transformation of the pp-wave background which is not the Lorentz transformation in the flat background. Moreover, we prove the exact correspondence between this low energy action and the second-order perturbation of supergravity action in the same background. We also prove the correspondence of the gauge transformation in both the actions. This construction is based on the BRST first quantization of superstrings in the pp-wave background in our previous paper.

Lie Derivatives along Antisymmetric Tensors, and the M-Theory Superalgebra

Free differential algebras (FDAs) provide an algebraic setting for field theories with antisymmetric tensors. The “presentation” of FDAs generalizes the Cartan-Maurer equations of ordinary Lie algebras, by incorporating p-form potentials. An extended Lie derivative along antisymmetric tensor fields can be defined and used to recover a Lie algebra dual to the FDA that encodes all the symmetries of the theory including those gauged by the p-forms. The general method is applied to the FDA of D = 11 supergravity: the resulting dual Lie superalgebra contains the M-theory supersymmetry anticommutators in presence of 2-branes. MSC 2010: 53Z05, 83F50.

Theory and phenomenology of spin-1 chiral particles

We consider all possible finite representations of the Lorentz group and their association with the spin properties of the particles. It is shown that, for a given nontrivial spin, there exist several nonequivalent representations differing in chirality, which in the massless case correspond to different particles with different helicities. A spin-1 case, which includes the standard field description by the vector-potential and a non-standard one by the second rank antisymmetric tensor field, is considered in detail. The first field transforms under the real representation (1/2,1/2), while the second one does so under the chiral representations (1,0) and (0,1). By considering spin-1 hadron resonances as an example, it is shown that these two fields describe two different types of particles existing in nature. This idea is further applied to the construction of the Standard Model extension using a new type of spin-1 chiral particles. Its phenomenological consequences are studied in detail.

Bulk antisymmetric tensor fields coupled to a dilaton in a Randall-Sundrum model

A string-inspired 3-form-dilaton-gravity model is studied in a Randall-Sundrum brane world scenario. As expected, the rank-3 antisymmetric field is exponentially suppressed. For each mass level, the mass spectrum is bigger than the one for the Kalb-Ramond field. The coupling between the dilaton and the massless Kaluza-Klein mode of the 3-form is calculated and the coupling constant of the cubic interactions obtained numerically. This coupling are of the order of Tev$^{-1}$, therefore there exist a possibility to find some signal of it at Tev scale.