[填空题]
Symmetry breaking occurs i ,or vn+ dl,k4eyuae ; o-3mgi-(eri7j cc:g)mn to l5cql6y fj kedw7vh0(y*,;phe electroweak theory at about $10^{-18}\ \text{m}$. Show that this corresponds to an energy that is on the order of the mass of the W boson ($M_W c^2 \approx 80\ \text{GeV}$). $mc^2$$\approx$ GeV
