The Big Bang, CPT, and neutrino dark matter

Abstract

We investigate the idea that the universe before the Big Bang is the $CPT$ reflection of the universe after the bang, both classically and quantum mechanically, so that the universe does {\it not} spontaneously violate $CPT$. We show how $CPT$ symmetry selects a preferred vacuum state for quantum fields on a $CPT$-invariant cosmological background spacetime. The universe before the bang and the universe after the bang may be viewed as a universe/anti-universe pair, emerging directly into the hot, radiation-dominated era we observe in our past. This, in turn, leads to a remarkably economical explanation of the cosmological dark matter. With no additional fields beyond Einstein gravity and the standard model of particle physics (including right-handed neutrinos), a ${\mathbb{Z}}_2$ symmetry stabilizes one of the right-handed neutrinos. We calculate its abundance in detail and show that, in order to match the observed dark matter density, its mass must be $4.8\times 10^8\mathrm{GeV}$. We obtain several further predictions, including: (i) that the three light neutrinos are majorana; (ii) that one of these is exactly massless; and (iii) that, in the absence of an epoch of cosmic inflation, there should be no primordial, long-wavelength gravitational waves. We also briefly discuss the natural origin of the matter-antimatter asymmetry within this picture and possibilities for explaining the cosmological perturbations.

25 pages, matches version published in Annals of Physics

References in corpus (4)

• CPT-Symmetric Universe
• Constraints on Sterile Neutrino Dark Matter
• Upgoing ANITA events as evidence of the CPT symmetric universe
• A search for IceCube events in the direction of ANITA neutrino candidates

Cited by in corpus (9)

• Accelerating cosmology from a holographic wormhole
• Macroscopic quantum tunneling: from quantum vortices to black holes and Universe
• Thermodynamic solution of the homogeneity, isotropy and flatness puzzles (and a clue to the cosmological constant)
• Visions in Quantum Gravity
• Axion-Sterile-Neutrino Dark Matter
• Stueckelberg Bosons as an Ultralight Dark Matter Candidate
• On dimension of tetrads in effective gravity
• Cancelling the vacuum energy and Weyl anomaly in the standard model with dimension-zero scalar fields
• Sterile Neutrino Dark Matter from Generalized $CPT$-Symmetric Early-Universe Cosmologies