CHAPTER 27 - Particles and the universe

Abstract

Some of the fundamental characteristics of elementary particles can be deduced from astrophysical observational data with much higher accuracy than from laboratory experiments—such as the upper bounds on the mass of the photon and of different types of neutrinos, restrictions on the mass and lifetimes of hypothetical neutral leptons, the upper bound on the number of different types of neutrino, and finally, the arguments in favor of quark confinement. This chapter discusses some of these restrictions on the basis of the hot universe model. The universe contains several protons and many electrons per cubic meter. The number of photons in the universe is greater than that of protons by a factor of approximately 10 9 . These photons exist in the form of radiation; the total energy of this microwave radiation is smaller by four orders of magnitude than the total mass of protons. It means that although the number of relic photons is large, their role is negligible in comparison to that of electrons and protons. The theory of the hot universe shows that the current number of relic neutrinos is of approximately the same order of magnitude as the number of photons. The theory gives today's concentration of relic neutrinos, which it makes it possible to find the upper bound on the masses of these particles.