Photoproduction of Boson Pairs in a Radiation-Dominated Universe. II

The average number of pairs of scalar massive particles produced by a decaying photon in a radiation-dominated universe is calculated. The dependence of the expression obtained on the energy of the initial photon is investigated. Numerical estimates are found for the formative time t₀ of the processes of decay of photons in an early universe and for the total number N^(±)_{out pair} of photoproduced scalar pairs. The estimates are: t₀ 3 min and N^(±)_{out pair} 10³¹·N^(±)₀(0), where N^(±)₀(0) is the total number of pairs produced from the vacuum of a free quantized field.