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![In the KK mode degenerate case, we plot the correlation between the δg W tb = g W tb /g − 1 and the mass difference of the first KK modes of light quark and top quark. The effective electroweak scale T is fixed to be 2 TeV, and c, c T ∈ [−0.4, 0.4].](profile/Sanghyeon-Chang/publication/235534933/figure/fig3/AS:393373249753090@1470798899125/In-the-KK-mode-degenerate-case-we-plot-the-correlation-between-the-dg-W-tb-g-W-tb-g.png)
In the KK mode degenerate case, we plot the correlation between the δg W tb = g W tb /g − 1 and the mass difference of the first KK modes of light quark and top quark. The effective electroweak scale T is fixed to be 2 TeV, and c, c T ∈ [−0.4, 0.4].
Source publication
Recently bulk Randall-Sundrum theories with the gauge group SU(2)L×SU(2)R×U(1)B-L have drawn a lot of interest as an alternative to the electroweak symmetry breaking mechanism. These models are in better agreement with electroweak precision data since custodial isospin symmetry on the IR-brane is protected by the extended bulk gauge symmetry. We co...
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Citations
... The two regions y < 0 and y > 0 are identified by the Z 2 symmetry. The boundary conditions for fields propagating in the bulk are dictated by that symmetry (see, for example, the discussion in [35,36] for the case D ¼ 4). ...
... We can also consider the case when the Z 2 parities of the field with respect to the branes y ¼ 0 and y ¼ a have opposite signs (for different combinations of parities in the case of vector fields see [36]). For example, let us discuss the field odd under the reflection with respect to the brane y ¼ 0 and even under the reflection with respect to the second brane at y ¼ a. ...
We evaluate the correlators for the vector potential and for the field strength tensor of the electromagnetic field in the geometry of two parallel planar plates in AdS spacetime. Two types of boundary conditions are considered on the plates. The first one is a generalization of the perfect conductor boundary condition and the second one corresponds to the confining boundary conditions. By using the expressions for the correlators, the vacuum expectation values (VEVs) of the photon condensate and of the electric and magnetic fields squared are investigated. As another important local characteristic of the vacuum state we consider the VEV of the energy-momentum tensor. The Casimir forces acting on the plates are decomposed into the self-action and interaction parts. It is shown that the interaction forces are attractive for both types of boundary conditions. At separations between the plates larger than the curvature radius of the background geometry they decay exponentially as functions of the proper distance. The self-action force per unit surface of a single plate does not depend on its location and depending on the boundary condition and on the number of spatial dimensions can be either attractive or repulsive with respect to the AdS boundary. By using the generalized zeta function technique we also evaluate the total Casimir energy. Applications are given in Z2-symmetric braneworld models of the Randall-Sundrum type for vector fields with even and odd parities.
... The brane is located at y = 0. Hence, in the corresponding setup, two copies of the R-region are employed with z 0 = a. The boundary conditions on the bulk fields at the location of the brane are obtained by integrating the field equations about y = 0 (see, e.g., the discussions in [26,40,67,76,79,80]). ...
We review the results of investigations for brane-induced effects on the local properties of quantum vacuum in background of AdS spacetime. Two geometries are considered: a brane parallel to the AdS boundary and a brane intersecting the AdS boundary. For both cases, the contribution in the vacuum expectation value (VEV) of the energy–momentum tensor is separated explicitly and its behavior in various asymptotic regions of the parameters is studied. It is shown that the influence of the gravitational field on the local properties of the quantum vacuum is essential at distance from the brane larger than the AdS curvature radius. In the geometry with a brane parallel to the AdS boundary, the VEV of the energy–momentum tensor is considered for scalar field with the Robin boundary condition, for Dirac field with the bag boundary condition and for the electromagnetic field. In the latter case, two types of boundary conditions are discussed. The first one is a generalization of the perfect conductor boundary condition and the second one corresponds to the confining boundary condition used in QCD for gluons. For the geometry of a brane intersecting the AdS boundary, the case of a scalar field is considered. The corresponding energy–momentum tensor, apart from the diagonal components, has nonzero off-diagonal component. As a consequence of the latter, in addition to the normal component, the Casimir force acquires a component parallel to the brane.
... The brane is located at y = 0. Hence, in the corresponding setup two copies of the R-region are employed with z 0 = a. The boundary conditions on the bulk fields at the location of the brane are obtained by integrating the field equations about y = 0 (see, e.g., the discussions in [16,34,37,38,39,40]). For scalar fields even under the reflection with respect to the brane, the Robin boundary condition is obtaned with the coefficient β = −2/(c b +4Dξ/a), where c b is the brane mass term. ...
We review the results of investigations for brane-induced effects on the local properties of quantum vacuum in background of AdS spacetime. Two geometries are considered: a brane parallel to the AdS boundary and a brane intersecting the AdS boundary. For both these cases the contribution in the vacuum expectation value (VEV) of the energy-momentum tensor is separated explicitly and its behavior in various asymptotic regions of the parameters is studied. It is shown that the influence of the gravitational field on the local properties of the quantum vacuum is essential at distance from the brane larger than the AdS curvature radius. In the geometry with a brane parallel to the AdS boundary the VEV of the energy-momentum tensor is considered for scalar field with the Robin boundary condition, for Dirac field with the bag boundary condition and for the electromagnetic field. In the latter case two types of boundary conditions are discussed. The first one is a generalization of the perfect conductor boundary condition and the second one corresponds to the confining boundary condition used in QCD for gluons. For the geometry of a brane intersecting the AdS boundary, the case of a scalar field is considered. The corresponding energy-momentum tensor, apart from the diagonal components, has nonzero off-diagonal component. As a consequence of the latter, in addition to the normal component, the Casimir force acquires a component parallel to the brane.
... As a result, in the geometry of two branes one has four different combinations of the boundary conditions corresponding to different choices of u j in the set ðu 1 ; u 2 Þ (for different combinations of boundary conditions imposed on fermionic fields in two-brane models see also [38]). For given ðu 1 ; u 2 Þ, the mode functions obeying the boundary condition on the brane y ¼ y 1 are presented as ...
The vacuum expectation value (VEV) of the fermionic current density is investigated in the geometry of two parallel branes in locally AdS spacetime with a part of spatial dimensions compactified to a torus. Along the toral dimensions quasiperiodicity conditions are imposed with general phases and the presence of a constant gauge field is assumed. The influence of the latter on the VEV is of the Aharonov-Bohm type. Different types of boundary conditions are discussed on the branes, including the bag boundary condition and the conditions arising in Z2-symmetric braneworld models. Nonzero vacuum currents appear along the compact dimensions only. In the region between the branes they are decomposed into the brane-free and brane-induced contributions. Both these contributions are periodic functions of the magnetic flux enclosed by compact dimensions with the period equal to the flux quantum. Depending on the boundary conditions, the presence of the branes can either increase or decrease the vacuum current density. For a part of boundary conditions, a memory effect is present in the limit when one of the branes tends to the AdS boundary. Unlike to the fermion condensate and the VEV of the energy-momentum tensor, the VEV of the current density is finite on the branes. Applications are given to higher-dimensional generalizations of the Randall-Sundrum models with two branes and with toroidally compact subspace. The features of the fermionic current are discussed in odd-dimensional parity and time-reversal symmetric models. The corresponding results for three-dimensional spacetime are applied to finite length curved graphene tubes threaded by a magnetic flux. It is shown that a nonzero current density can also appear in the absence of the magnetic flux if the fields corresponding to two different points of the Brillouin zone obey different boundary conditions on the tube edges.
The leptogenesis in the warped extra‐dimension model with RS1 background is studied in this paper. We use the bulk standard model as a framework where the bulk
SU
(2)
L
×
SU
(2)
R
× U(1)
B−L
is broken only on the boundaries. Lepton asymmetry can be generated through B‐L breaking term on Planck brane and can be enhanced to the observed value, if the additional bulk right‐handed neutrinos are degenerated.
Recent CDF measurement of the Bs-Bs oscillation frequency, at the Tevatron
imposes significant constraint on various models for new physics. A warped
extra-dimension model with custodial isospin symmetry accommodates the Bd-Bd
mixing at tree level mainly through the Kaluza-Klein gluons. This is due to the
misalignment between the bulk gauge eigenstates and the localized Yukawa
eigenstates of the bulk fermions. We adopt the universal 5D Yukawa coupling
model where all Yukawa couplings are of order one. The SM fermion mass spectra
and mixings are controlled by the bulk Dirac mass parameters. With two versions
of the hadronic parameter values, we investigate the implication of the
observed BB mixings on this model. The CP-violating effects on the Bd system is
shown to provide very strong constraint: The first Kaluza-Klein mass of a gluon
has its lower bound about 3.7 TeV with 1 sigma uncertainty.
Although the spectacular experimental achievements of particle physics in the last decade have strengthened the Standard Model (SM) as an adequate description of
nature, they have also revealed that the SM matter represents a mere 5% or so of the energy density of the Universe, which clearly points to some physics beyond the SM despite the desperate lack of direct experimental evidence. The sector responsible for the spontaneous breaking of the SM electroweak symmetry is likely to be the first to provide experimental hints at this new physics. The aim of this review is, after briefly introducing SM physics and the conventional Higgs mechanism, to give a survey of recent ideas on how the dynamics of electroweak symmetry breaking can be explained.
The custodial Randall-Sundrum model based on SU(2){sub L}xSU(2){sub R}xU(1){sub B-L} generates new flavor-changing-neutral-current (FCNC) phenomena at tree level, mediated by Kaluza-Klein (KK) neutral gauge bosons. Based on two natural assumptions of universal 5D Yukawa couplings and no cancellation in explaining the observed standard model (SM) fermion mixing matrices, we determine the bulk Dirac mass parameters. Phenomenological constraints from lepton-flavor violations are also used to specify the model. From the comprehensive study of BK*l{sup +}l{sup '-}, we found that only the BK*e{sup +}e decay has sizable new physics effects. The zero value position of the forward-backward asymmetry in this model is also evaluated, with about 5% deviation from the SM result. Other effective observables are also suggested such as the ratio of two differential (or partially integrated) decay rates of BK*e{sup +}e and BK*{sup +}. For the first KK gauge boson mass of M{sub A}{sup (1)}=2-4 TeV, we can have about 10%-20% deviation from the SM results.
