“…Recently other possible universality classes have been studied 1,27,28,29,30,31,32,33,34,35,36,37,38,39,40 . Among them is a pair contact process with diffusion (PCPD), the critical behavior of which has not yet been described analytically 8,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56 .…”