10 research outputs found
Gauge hierarchy from a topological viewpoint?
In this work we explore an alternative to the central point of the
Randall-Sundrum brane world scenario, namely, the particular nonfactorizable
metric, in order to solve the hierarchy problem. From a topological viewpoint,
we show that the exponential factor, crucial in the Randall-Sundrum model,
appears in our approach, only due to the brane existence instead of a special
metric background. Our results are based in a topological gravity theory via a
non-standard interaction between scalar and non-abelian degrees of freedom and
in calculations about localized modes of matter fields on the brane. We point
out that we obtain the same results of the Randall-Sundrum model using only one
3-brane, since a specific choice of a background metric is no longer required.Comment: 10 pages, to appear in Physics Letters
Antisymmetric Tensor Fields in Randall Sundrum Thick Branes
In this article we study the issue of localization of the three-form field in
a Randall-Sundrum-like scenario. We simulate our membrane by kinks embedded in
D=5, describing the usual case (not deformed) and new models coming from a
specific deformation procedure. The gravitational background regarded includes
the dilaton contribution. We show that we can only localize the zero-mode of
this field for a specific range of the dilaton coupling, even in the deformed
case. A study about resonances is presented. We use a numerical approach for
calculations of the transmission coefficients associated to the quantum
mechanical problem. This gives a clear description of the physics involved in
the model. We find in this way that the appearance of resonances is strongly
dependent on the coupling constant. We study the cases and 5 for
and . The first value of give us one
resonance peak for and no resonances for . The second value of
give us a very rich structure of resonances, with number deppending on
the value of .Comment: 7 pages, 3 figure
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
Kalb–Ramond field localization on the Bloch brane
This work deals with new results on the Kalb-Ramond (KR) field localization
in braneworld models. We consider a five-dimensional warped spacetime with an
embedded 4D thick brane which is generated by two real scalar fields coupled
with gravity (the so called Bloch brane). We find a KR field zero mode
localized with the inclusion of the dilaton coupling. Analyzing the massive
spectrum, we detected a series of resonant modes that arise from the solutions
of the Schr\"odinger-like equation for KR field. The effects of the brane
thickness and of the dilaton coupling over the resonance structures are
determined. Such analysis is extended to the resonance lifetimes of the massive
modes, allowing a better understanding on the localization mechanism of the
model.Comment: 18 pages, 6 figure