I'm reviewing this book Warped Passages by Lisa Randall and a sentence caused me some incomprehension. Somewhere in it she stated: "The weak gauge boson masses tell us the precise value of the energy at which the weak force symmetry is spontaneously broken. That energy is 250 GeV, the weak scale energy, very close to the masses of the weak gauge bosons, the W-, the W+ and the Z. When particles have energy greater than 250 Gev, interactions occur as if the symmetry is preserved, but when their energy is less than 250 Gev, the symmetry is broken and weak gauge bosons act as if they have mass. With the correct value of the nonvanishing Higgs field, the weak force symmetry is spontaneously broken at the right energy, and the weak gauge bosons get precisely the right mass." I'd like to know something. Why, if the energy of the accelerator is above 250 GeV. Can they see the weak bosons losing mass and become massless, just like the photons? And why the 250 GeV value? The mass of the Z is 91.1876 GeV and the Ws is 80.385 GeV. Where did Lisa come up with 250 GeV (which is exactly double the mass of the Higgs.. the book written in 2006, so she didn't know).