An improved formulation for three-charged particles correlations in terms of Coulomb wave functions with degree of coherence

The recent data for Bose-Einstein Correlations (BEC) of three-charged particles obtained by NA44 Collaboration have been analysed using theoretical formula with Coulomb wave functions. It has been recently proposed by Alt et al. It turns out that there are discrepancies between these data and the respective theoretical values. To resolve this problem we seek a possibly improved theoretical formulation of this problem by introducing the degree of coherence for the exchange effect due to the BEC between two-identical bosons. As a result we obtain an improved formulation for the BEC of three-charged particles showing to a good agreement with the experimental data of NA44 Collaboration. This indicates that the interaction region in the S + Pb collisions at 200 GeV/c per nucleon is equal to about 1.5 fm.