I just like to know if the ps vita is powerful enough for unreal engine 4
No, PS Vita is not supported by UE4
But UE3 does support Vita, though if you want to license UE3 that’s more complicated and you’ll have to email Epic licensing about that.
I think it could run if it was supported, UE4 runs on weaker mobile hardware then Vita. Problem is the same as Wii U user base size, it’s too small and both consoles considered “dead” by many, ofcorse thats imo, not Epic opinion