Beyond the maximum, stopping power decreases approximately like 1/v with increasing particle velocity v, but after a minimum, it increases again. A minimum ionizing particle (MIP) is a particle whose mean energy loss rate through matter is close to the minimum. In many practical cases, relativistic particles (e.g., cosmic-ray muons) are minimum ionizing particles. An important property of all minimum ionizing particles is that β β γ γ ≃ ≃ 3 is approximately true where β β and γ γ are the usual relativistic kinematic quantities. Moreover, all of the MIPs have almost the same energy loss in the material which value is: − − d E d x ≃ ≃ 2 MeV g cm − − 2 .