Spin-half fermions with mass dimension one: theory, phenomenology, and dark matter

Abstract

We provide the first details on the unexpected theoretical discovery of a\nspin-one-half matter field with mass dimension one. It is based upon a complete\nset of dual-helicity eigenspinors of the charge conjugation operator. Due to\nits unusual properties with respect to charge conjugation and parity, it\nbelongs to a non-standard Wigner class. Consequently, the theory exhibits\nnon-locality with (CPT)^2 = - I. We briefly discuss its relevance to the\ncosmological `horizon problem'. Because the introduced fermionic field is\nendowed with mass dimension one, it can carry a quartic self-interaction. Its\ndominant interaction with known forms of matter is via Higgs, and with gravity.\nThis aspect leads us to contemplate the new fermion as a prime dark matter\ncandidate. Taking this suggestion seriously we study a supernova-like explosion\nof a galactic-mass dark matter cloud to set limits on the mass of the new\nparticle and present a calculation on relic abundance to constrain the relevant\ncross-section. The analysis favours light mass (roughly 20 MeV) and relevant\ncross-section of about 2 pb. Similarities and differences with the WIMP and\nmirror matter proposals for dark matter are enumerated. In a critique of the\ntheory we bare a hint on non-commutative aspects of spacetime, and\nenergy-momentum space.\n