ABSTRACT
The end of inflation marked the triggering of Big Bang cosmology. The assumption is that the oscillations of the inflaton have associated with them quanta, whose decay gave birth to what is known as the Radiation Era. Massless particles moving at the speed of light were the constituents of this radiation. There could have been all kinds of particles created at those extremes of temperature which the authors would not be able to observe today. The particles they will concentrate on are the ones they can observe that are the building blocks of nature. These, together with their antiparticles and the forces between them, form the foundation of the Standard Model of Particle Physics. The symmetry aspects of the theory require these particles and the force carriers of their interactions, known as gauge bosons, to be massless.
