Gauge Field Localization Research Articles

Study on Kalb–Ramond field localization in f(T) gravity theory with a noncanonical scalar field

In this paper, we investigate the localization of five-dimensional tensor gauge fields called Kalb–Ramond fields in the modified teleparallel braneworld models. The aforementioned branes are generated by gravity coupled to a real scalar field with nonstandard kinetic terms. For two specific forms of the noncanonical expressions, background scalar field solutions are particularly discussed in the presence of different forms of [Formula: see text] gravity. By applying nonminimal coupling functions in the tensor gauge field action, it is shown that massless zero modes of Kalb–Ramond gauge fields can be localized on the [Formula: see text] branes with noncanonical scalar fields. We also find that potentials of Kalb–Ramond massive modes are volcano-like regarding the equation of motion in the supersymmetric quantum mechanic scenario. Furthermore, the effects of parameters that control the deviation of the usual teleparallel theory are considered on the massless Kaluza–Klein mode and effective potential.

Localization of abelian gauge fields with Stueckelberg-like geometrical coupling on f(T, B)-thick brane

In the context of f(T, B) modified teleparallel gravity, we investigate the influence of torsion scalar T and boundary term B on the confinement of both the gauge vector and Kalb–Ramond fields. Both fields require a suitable coupling in five-dimensional braneworld scenarios to yield a normalizable zero mode. We propose a Stueckelberg-like geometrical coupling that non-minimally couples the fields to the torsion scalar and boundary term. To set up our braneworld models, we use the first-order formalism in which two kinds of superpotential are taken: sine-Gordon and phi ^{4}-deformed. The geometrical coupling is used to produce a localized zero mode. Moreover, we analyze the massive spectrum for both fields and obtain possible resonant massive modes. Furthermore, we do not find tachyonic modes leading to a consistent thick brane.

Gauge field localization in branes: coupling to a scalar function and coupling to torsion in teleparallel gravity scenario

This paper is aimed at investigating the behavior of gauge vector and tensor fields on thick brane in f(T) gravity. This thick brane is not capable of providing a normalizable zero mode for both gauge and Kalb Ramond fields. To overcome this problem, we propose two distinct types of gauge-invariant couplings. In the first coupling, the fields are minimally coupled to the scalar field responsible for generating the thick brane. In the second coupling, we use the geometric coupling in which the fields are non-minimally coupled to torsion. Another issue that we investigate is resonant modes, which allow us to understand the massive spectrum of fields. Indeed we note that an internal structure appears for the Kalb–Ramond massive solutions and both couplings show resonant modes of the massive spectrum.

Gauge field localization in the linear dilaton background

We study dynamical self-localization of gauge theories in higher dimensions. Specifically, we consider a 5D U(1) gauge theory in the linear dilaton (clockwork) background, with anisotropic gauge couplings along the transverse (fifth) direction and the longitudinal (four-dimensional) directions. By using lattice techniques, we calculate the space plaquettes and the helicity moduli and we determine the phase diagram of the model. We find strong evidence that the model exhibits a new phase, a layer phase, where the four-dimensional physics decouples from the five-dimensional dynamics. The layer phase corresponds to a strong force along the fifth direction and a Coulomb phase along the four-dimensional longitudinal directions. This is in accordance with the clockwork mechanism where light particles with exponentially suppressed interactions are generated in theories with no fundamental small parameters.

Universal aspects of U(1) gauge field localization on branes in D-dimensions

In this work, we study the general properties of the D-vector field localization on (D − d − 1)-brane with co-dimension d. We consider a conformally flat metric with the warp factor depending only on the transverse extra dimensions. We employ the geometrical coupling mechanism and find an analytical solution for the U(1) gauge field valid for any warp factor. Using this solution we find that the only condition necessary for localization is that the bulk geometry is asymptotically AdS. Therefore, our solution has an universal validity for any warp factor and is independent of the particular model considered. We also show that the model has no tachyonic modes. Finally, we study the scalar components of the D-vector field. As a general result, we show that if we consider the coupling with the tensor and the Ricci scalar in higher co-dimensions, there is an indication that both sectors will be localized. As a concrete example, the above techniques are applied for the intersecting brane model. We obtain that the branes introduce boundary conditions that fix all parameters of the model in such a way that both sectors, gauge and scalar fields, are confined.

Localization of the Standard Model via the Higgs mechanism and a finite electroweak monopole from non-compact five dimensions

We propose a minimal and self-contained model in non-compact flat five dimensions which localizes the Standard Model (SM) on a domain wall. Localization of gauge fields is achieved by the condensation of Higgs field via a Higgs dependent gauge kinetic term in five-dimensional Lagrangian. The domain wall connecting vacua with unbroken gauge symmetry drives the Higgs condensation which provides both electroweak symmetry breaking and gauge field localization at the same time. Our model predicts higher-dimensional interactions $|H|^{2n}(F_{\mu\nu})^2$ in the low-energy effective theory. This leads to two expectations: The one is a new tree-level contribution to $H \to \gamma\gamma$ ($H \to gg$) decay whose signature is testable in future LHC experiment. The other is a finite electroweak monopole which may be accessible to the MoEDAL experiment. Interactions of translational Nambu-Goldstone boson is shown to satisfy a low-energy theorem.

Localized non-Abelian gauge fields in non-compact extra dimensions

Dynamical localization of non-Abelian gauge fields in non-compact flat $D$ dimensions is worked out. The localization takes place via a field-dependent gauge kinetic term when a field condenses in a finite region of spacetime. Such a situation typically arises in the presence of topological solitons. We construct four-dimensional low-energy effective Lagrangian up to the quadratic order in a universal manner applicable to any spacetime dimensions. We devise an extension of the $R_\xi$ gauge to separate physical and unphysical modes clearly. Out of the D-dimensional non-Abelian gauge fields, the physical massless modes reside only in the four-dimensional components, whereas they are absent in the extra-dimensional components. The universality of non-Abelian gauge charges holds due to the unbroken four-dimensional gauge invariance. We illustrate our methods with models in $D=5$ (domain walls), in $D=6$ (vortices), and in $D=7$.

Non-Abelian gauge field localization on walls and geometric Higgs mechanism

Combining the semi-classical localization mechanism for gauge fields with $N$ domain wall background in a simple $SU(N)$ gauge theory in five space-time dimensions we investigate the geometric Higgs mechanism, where a spontaneous breakdown of the gauge symmetry comes from splitting of domain walls. The mass spectra are investigated in detail for the phenomenologically interesting case $SU(5) \to SU(3)\times SU(2)\times U(1)$ which is realized on a split configuration of coincident triplet and doublet of domain walls. We derive a low energy effective theory in a generic background using the moduli approximation, where all non-linear interactions between effective fields are captured up to two derivatives. We observe novel similarities between domain walls in our model and D-branes in superstring theories.

Gauge Field Localization on Deformed Branes

In this paper, we utilise the Chumbes-Holf da Silva-Hott (CHH) mechanism to investigate the issue of gauge field localization on a deformed brane constructed with one scalar field, which can be coupled to gravity minimally or non-minimally. The study of deformed defects is important because they contain internal structures which may have implications in braneworld models. With the CHH mechanism, we find that the massless zero mode of gauge field, in the case of minimal or non-minimal coupling is localized on the brane. Moreover, in the case of non-minimal coupling, it is shown that, when the non-minimal coupling constant is larger than its critical value, then the zero mode is localized on each sub brane.

Localization of abelian gauge fields on thick branes

In this work, we explore a mechanism for abelian gauge field localization on thick branes based on a five-dimensional Stueckelberg-like action. A normalizable zero mode is found through the identification of a suitable coupling function between the brane and the gauge field. The same mechanism is studied for the localization of the abelian Kalb--Ramond field.

Gauge field localization on the brane through geometrical coupling

In this paper we consider a geometrical Yukawa coupling as a solution to the problem of gauge field localization. We show that upon dimensional reduction the vector field component of the field is localized but the scalar component (A5) is not. We show this for any smooth version of the Randall–Sundrum model. The covariant version of the model with geometrical coupling simplifies the generalization to smooth versions generated by topological defects. This kind of model has been considered some time ago, but there it has been introduced with two free parameters in order to get a localized solution which satisfy the boundary conditions: a mass term in five dimensions and a coupling with the brane. The boundary condition fixes one of them and the model is left with one free parameter M. First we show that by considering a Yukawa coupling with the Ricci scalar it is possible to unify these two parameters into just one fixed by the boundary condition. With this we get a consistent model with no free parameters and the mass term can be interpreted as a coupling to the cosmological constant.

Vector and fermion fields on a bouncing brane with a decreasing warp factor in a string-like defect

In a recent work, a model has been proposed where a brane is made of a scalar field with bounce-type configurations and embedded in a bulk with a string-like metric. This model produces an AdS scenario where the components of the energy–momentum tensor are finite and have its positivity ensured by a suitable choice of the bounce configurations. In the present work, we study the issue of gauge and fermion field localization in this scenario. In contrast with the five-dimensional case here the gauge field is localized without the dilaton contribution. Nevertheless, it is remarkable that the localization of the fermion field depends on the introduction of a minimal coupling with the angular component of the gauge field, which differs clearly from five-dimensional scenarios. Furthermore, we perform a qualitative analysis of the fermionic massive modes and conclude that only left-handed fermions could be localized in the brane.

More on divergences in brane world models

In this paper a model in a space-time with compact extra dimension is presented, describing five-dimensional fermion fields interacting with an electromagnetic field localized on a brane. This model can be considered as a toy model for examining possible consequences of the localization of gauge fields on a brane. It is shown that in the limit of infinite extra dimension, the lowest-order amplitudes of some processes in the resulting four-dimensional effective theory are divergent. Such a ``localization catastrophe'' can be inherent to more realistic brane world models with infinite extra dimensions.

Gauge field localization on the Bloch brane

We present new results on the localization of gauge fields in thick brane models. The four-dimensional observable universe is considered to be a topological defect which is generated by two scalar fields coupled with gravity embedded in a five-dimensional space-time. Like other thick brane models, the Bloch brane setup is not capable of supporting gauge field localization. In order to circumvent this problem we include the dilaton field and, as a result, obtain normalizable solutions. In addition, by writing the equations of motion as Schroedinger-like equations, we have found new kinds of resonances in the massive spectrum which appear also for heavy modes. This is in sharp contrast to what is commonly found in previous analog studies, where only light modes become resonant. At specific energies, the wave solutions exhibit very high amplitudes within the membrane. The influence of the dilaton coupling and of the internal structure on the resonant modes are also discussed.

Localization of matter fields and non-Abelian gauge fields on domain walls

We propose a method for simultaneous localization of non-Abelian gauge fields and matter fields with minimal interaction on domain walls using U(N)c gauge theory with SU(N)L × SU(N)R × U(1)A flavor symmetry. Localization of non-Abelian fields is achieved using field-dependent gauge coupling. We find that effective Lagrangian up to second order of derivatives for low energy fluctuations resembles a chiral model from hadron physics with additional minimal interactions of pions with localized gauge fields together with nonlinear interactions of moduli fields. This result provides a step towards a realistic model building of brane-world scenario using topological solitons.

Tensor gauge field localization on a string-like defect

This work is devoted to the study of tensor gauge fields on a string-like defect in six dimensions. This model is very successful in localizing fields of various spins only by gravitational interaction. Due to problems of field localization in membrane models we are motivated to investigate if a string-like defect localizes the Kalb–Ramond field. In contrast to what happens in Randall–Sundrum and thick brane scenarios we find a localized zero mode without the addition of other fields in the bulk. Considering the local string defect we obtain analytical solutions for the massive modes. Also, we take the equations of motion in a supersymmetric quantum mechanics scenario in order to analyze the massive modes. The influence of the mass as well as the angular quantum number in the solutions is described. An additional analysis on the massive modes is performed by the Kaluza–Klein decomposition, which provides new details about the KK masses.

Localization of gauge fields and Maxwell-Chern-Simons theory

We propose an explicit model, where an axionic domain wall dynamically localizes a U(1)-component of a nonabelian gauge theory living in a 3+1 dimensional bulk. The effective theory on the wall is 2+1d Maxwell-Chern-Simons theory with a compact U(1) gauge group. This setup allows us to understand all key properties of MCS theory in terms of the dynamics of the underlying 3+1 dimensional gauge theory. Our findings can also shed some light on branes in supersymmetric gluodynamics.

Localization of gauge bosons in the 5D standing wave braneworld

We investigate the problem of localization of gauge fields within the 5D standing wave braneworld model and show that in the case of increasing warp factor there exist normalizable vector field zero modes on the brane.

Domain Walls and Gauge Field Localization in Strongly-Coupled Pure Yang-Mills Theories

We present a mechanism of gauge field localization on a domain wall within the framework of strongly coupled pure Yang-Mills theory.

Gauge field localization on brane worlds

We consider the effects of spacetime curvature and brane thickness on the localization of gauge fields on a brane via kinetic terms induced by localized fermions. We find that in a warped geometry with an infinitely thin brane, both the infrared and the ultraviolet behavior of the electromagnetic propagator are affected, providing a more stringent bound on the brane's tension than that coming from the requirement of four-dimensional gravity on the brane. On the other hand, for a thick wall in a flat spacetime, where the fermions are localized by means of a Yukawa coupling, we find that four-dimensional electromagnetism is recovered in a region bounded from above by the same critical distance appearing in the thin case, but also from below by a new scale related to the brane's thickness and the electromagnetic couplings. This imposes very stringent bounds on the brane's thickness which seem to invalidate the localization mechanism for this case.