Exotic Elko on string-like defects in six dimensions

¹ Departamento de Física, Universidade Federal do Ceará - C.P. 6030, 60455-760 Fortaleza, CE, Brazil
² Centro de Matemática, Computação e Cognição, Universidade Federal do ABC 09210-580, Santo André, SP, Brazil

^(a) davi@fisica.ufc.br
^(b) roldao.rocha@ufabc.edu.br
^(c) carlos@fisica.ufc.br

Received: 22 December 2016
Accepted: 14 April 2017

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.