Higgs events
Your challenge is now to select collisions where a Higgs boson could have been produced. But how can this be done when in reality a Higgs boson of mass 125 geV is even heavier than the Z boson that only lives for 3×10-25 seconds?
How could you “see” the Higgs boson if it instantly disappears? Answer: By the knowledge of how it decays or "dies", and the Higgs boson can decay in a multitude of ways.
There are some differences between the Higgs boson and the Z boson that we don’t need to worry about here. Because the Higgs field is responsible for masses of particles, the Higgs boson will have the tendency to couple more to heavy particles. For the moment we simply use the link where we put together the ways a Higgs of mass 125 GeV decays.
In your search you will only focus on two of the “easiest” detectable decay-products, namely
- ZZ*, followed by the Z decay to a pair of lepton-antilepton
- γγ
The cartoon drawings visualize the 2 ways the heavy Higgs boson decays.
It so happens that the leptons from the Z particles and the photons are stable enough for the detector to register them. This is crucial and makes the detection of short-lived particles like the Z boson or Higgs boson possible.