At particle colliders, subatomic particles of relatively low mass are accelerated to very nearly the speed of light, so that their combined energy when smashed together head-on is sufficient to produce more exotic particles of much greater mass.
Suppose you could do this sort of thing on a macroscopic scale. How fast would you have to smash two 1 kg chickens together to make a 400 kg cow? Express your answer as a result for 1 - β.