[填空题]
The lifetimes listed;. bqs5x7d,0cw4ki 6oop oain in Tri l09js1c *ffable 32-2 are in terms of proper time, measured in a reference frame where the particle is at rc fj ls0f91*irest. If a tau lepton is created with a kinetic energy of 450 MeV, how long would its track be as measured in the lab, on average, ignoring any collisions? $\Delta x_{\text{lab}} = $ $ \times 10^{-5}\ \text{m}$
