Exotic Elko on string-like defects in six dimensions

Abstract

We analyse the trapping of eigenspinors of the charge conjugation operator with dual helicity (Elko), in thin and thick string-like models with codimension-2. Elko spinor fields describe mass dimension one fermions in four dimensions (and, correspondingly, mass dimension two fermions in six dimensions), that represent natural dark matter prime candidates. This dark spinor has many applications, from particle physics to cosmology. On the other hand, six-dimensional brane-world models have, among other prominent features, the spontaneous confinement of free spin 1 fields and a mechanism that explains the mass hierarchy of fundamental fermions. In this paper, we use scalar couplings in order to confine the zero mode of Elko in six dimensions. Moreover, we use the Elko dark spinor features to propose an exotic coupling in order to remove the complex-valued terms in the massive Kaluza-Klein modes. Hence, we show that six dimensional models can resolve the main issues of Elko fields confinement presented in five dimensions.

Introduction to Extra Dimensions and Thick Braneworlds

“…Besides the above mentioned fields, some other fields such as Gravitino Fields [251], Elko Spinors [252][253][254][255], and new fermions [256] were also investigated in the content of extra dimensions and braneworlds.…”

Monopoles on string-like models and the Coulomb's law

“…To determine the lower bound for the brane thickness, the parameter c was identified in Ref. [29] as an effective mass of dark matter particles ∼ 10 −2 GeV, implying the brane thickness ∆ HC 6.4472 × 10 −1 GeV −1 = 1.276 × 10 −16 m.…”

“…It is remarkable to mention that in the scope of applications of brane-worlds models, several recent works perform the study of the informational entropy [1-7] underlying these scenarios, using Einstein-dilaton systems to derive phenomenologically compatible data. These models are used to respond to LHCb anomalies [8,9], and several others applications, in the context of black holes [10-12], dark matter [13] and inflationary universe theories [14][15][16].Six-dimensional (6D) anti-de Sitter (AdS 6 ) brane-worlds [17,18] have some interesting features, as the remarkable advantage of trapping the massless gauge fields with only gravity [19][20][21][22][23], in opposition to what occurs in 5D domain wall models [24] and DPG models [25], and minimally coupled Dirac fermions [23,[26][27][28][29], even when thin brane models are considered. In the context of Lorentz violation scenarios in brane-worlds, the massless four-dimensional (4D) graviton can be only confined in 6D models [30].…”

“…Again, as the parameter c can be identified to the effective mass of dark matter particles ∼ 10 −2 GeV[29], it yields the brane width ∆ 29.9336 × 10 −2 GeV −1 = 5.8914 × 10 −17 m.…”

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

“…By the way, the localization of the Elko spinor in a six-dimensional string-like model was considered in Ref. [96], recently.…”