New species of fermions and bosons, cosmological constant problem and a farewell to spin–statistics theorem

Abstract

If dark matter exists in the form of ultralight fermionic and bosonic species, then (a) it can accelerate evaporation of astrophysical black holes to the extent that their lifetimes can be reduced to astronomical time scales, a and (b) if there are extremely large number of such species it has the potential to solve the hierarchy problem [H. Davoudiasl, P. B. Denton and D. A. McGady, Phys. Rev. D 103 (2021) 055014; G. Dvali, Fortschr. Phys. 58 (2010) 528]. Here, we put forward a proposal that darkness of many of these new particles is natural, and in addition, the net zero point energy of the fermions exactly cancels that coming from the new bosons. The needed fermion–boson equality, and matching the fermion–boson degrees of freedom, comes about naturally. A very direct argument that allows the departure from the spin–statistics theorem is presented. a This happens in two steps: first, the relatively rapid evaporation of the ultralight particles, and the second slower one associated with a hundred or so ‘heavier’ particles of the standard model.