one knows that the system spends a longer time without emitting any particles in the hybrid model calculation.

Fig. \[HBT-fig2\] exhibits the freeze-out time dependence of the $\pi^-$ emission in central Pb+Pb at $E_{\rm lab}=20A$ GeV (left plot) and $E_{\rm lab}=158A$ GeV (right plot). It is clearly seen that there are almost no pions emitted before $\sim 10$fm$/c$ in the hybrid model calculations. This is easy to understand because even in the gradual hydro-freeze-out which is applied here, it takes a while until the first slices have cooled down and are frozen out from the hydrodynamic evolution. There is no particle emission from earlier times in contrast to the pure cascade calculation. For the BM-EoS, this effect is present even for a longer time since the expansion lasts longer [^6]. The on-the-average longer freeze-out time leads to an apparently larger size of the pion source. Furthermore, it is clear (and expected) that the EoS with larger latent heat (such as in the BM mode) leads to a longer emission duration of the particles (as seen in Fig. \[HBT-fig2\] when $t_f\gtrsim 15$fm$/c$) so that it produces larger HBT radii. This behaviour is clearly seen in the more time-dependent directions $R_L$ and 