Azimuthally Integrated HBT Parameters for Charged Pions in Nucleus-Nucleus Interactions versus Collision Energy

Figure 3

Energy dependence of volume of emission region at freeze-out for secondary charged pions in central heavy ion collisions , , in midrapidity region and at  GeV/. Equation (3) is used for calculation of volume values. Experimental results are shown for the same particle types and Coulomb corrections as well as in Figure 1. Error bars are only statistical (for NA44, total uncertainties). Smooth curves are derived from (3) and the fit results for , taking into account the point of the WA97 experiment [11]. The solid line corresponds to the fits of HBT radii by function (7) and dashed line to the fits by specific case , .