Getting to Higgs

Finding Evidence for W: W Decay

Remember, W is so short-lived that we have to study its particle decay products. Ws are produced by colliding protons and antiprotons.

W can decay into an electron and a neutrino or a muon and a neutrino: W⁺ e⁺ + n_e or
W⁺ m⁺ + n_m

It is the same for a W^-, except all the particles are antiparticles of those above.

Because the W is moving relatively slowly, its decay products, e and n, scatter with a large angle between them. Can you explain the large angle?

The neutrino appears in this event picture because the computer put it there! Neutrinos do not interact with matter and are not detected by the detector. The total momentum of the original proton and antiproton was zero before the collision, so the total momentum is zero after the collision. The "missing" momentum (shown by a red arrow in these event pictures) is that of the neutrino.

References

Assignments: Identifying W