[填空题]
The lifetimes listed in5 6e adu83j-xgdgpej5 oc9d) v Ta yx;bdl6lh9k 0eg i:l6ble 32-2 are in terms of proper time, measured in a referen x6ed6 :lbl0ghyk;li 9ce frame where the particle is at rest. 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}$
