Production of longitudinal polarized fermion pairs and of photon by gamma quantum in distributed nuclear charge field

The effect of nuclear charge diffuseness degree on the relative probabilities of spin states of the e+e--pair produced in the nuclear photoproduction reaction γ+(Ze)→(Ze)'+e++e-+γ is investigated with regard to helicities of S electron and Ssub(+) positron. The charge distribution in a nucleus is defined as a uniform, gaussian, and exponential distribution. Calculations are made for 27Al nucleus. Angular, energy, amd spin dependences for the photoproduction cross sections of e+e--pair and γ-quantum are studied. All types of charge distributions for the positron emission angle of 5 deg have a similar effect on probability of spin states of the Ssub(+)Ssub(-)=1 pair, decreasing it by 3 or 4% at incident γ-quantum energy of 0.5 GeV, and by 10% at 0.75 GeV. At 0.5 GeV the curves for the energy dependence of the relative probability of the Ssub(+)+Ssub(-)=1 pair spin states coincide for different charge distributions. But at 0.75 GeV each type of diffused charge is distinguished. The allowance for the nuclear size decreases the probability of spin states for the Ssub(+)+Ssub(-)=1 pair, but increases the probability of the Ssub(+)+Ssub(-)=-1 states