Localization of five-dimensional Elko spinors with non-minimal coupling on thick branes

Abstract

It has been found that the zero mode of a fivedimensional Elko spinor could be localized on branes by introducing a Yukawa-type coupling between the Elko spinor and the background scalar field or the Ricci scalar. However, the Yukawa-type coupling is not appropriate for all brane models. In this paper, we explore other localization mechanism for the Elko spinor by introducing the non-minimal coupling f (φ)L Elko between the five-dimensional Elko spinor and the background scalar field. We give the general expressions of the Elko zero mode and the function f (φ). Through two thick brane models and three concrete examples, we show that the Elko zero mode can be localized on the branes by this new mechanism. This provides us more possibilities of localizing the Elko zero mode.

Localization of Elko spinor fields in tachyonic de Sitter braneworld models

“…Recently, the authors of Ref. [41] has been introduced a new non-minimal coupling mechanism can provide the possibility of localizing the Elko zero mode on Minkowski branes. Since de Sitter and Anti-de Sitter branes have different properties from Minkowski branes thus localization of 5D Elko field on these brane has new results compared to those on Minkowski branes.…”

“…By following the procedure of Refs. [41,42] we have examined localization of massless Elko fields on de Sitter tachyonic branes with non minimal coupling mechanism by choosing two different forms of the auxiliary function K (w) = 0 and K (w) = tanh(w). Results are similar to the ones obtained in the case of de Sitter brane in Ref.…”

“…An Elko field which is the eigenspinor of the charge conjugation operator with one mass dimension can be considered as a candidate of dark matter [36,37]. Also, localization of five-dimensional Elko spinor fields can be achieved in Minkowski thick branes by Yukawatype coupling mechanism [38][39][40] and non-minimal coupling mechanism [41]. Furthermore, it was found in Refs.…”

Constraints on generalized Eddington-inspired Born-Infeld branes

“…To check whether the background solution corresponds to a thick braneworld model, we should discuss the energy density of the brane. As we know, in most braneworld models [49,50], the vacuum of the scalar field is usually located at the boundary of the extra dimension, and the energy density of the brane is contributed by the scalar field only. So, one should subtract the contribution from the cosmological constant, which may exist in the scalar potential and may lead to a nonzero vacuum energy density, to fix the energy density to be zero at the boundary.…”

Smooth braneworld in 6-dimensional asymptotically AdS spacetime

“…It shows that a free massless scalar field and graviton are localized but a free U(1) gauge field is not. Hence, the localization mechanisms of gauge fields have been widely studied [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The usual way to localize the U(1) gauge field is adding couplings [22-25, 27-29, 31, 34].…”