What is the Higgs Boson and How do
What is the Higgs Boson and How do we find it? ?
The Standard Model describes how the fundamental particles interact. Photons Quarks Leptons & Neutrinos Particles exchanged in the weak and strong forces
The Standard Model Quarks Leptons & Neutrinos Before Higgs: • The equation of the standard model-- which tells us how all the elementary particles interact-- worked very well, but only if all of the particles have 0 mass. • We know this isn’t true! Particles do have mass. • But if you add the mass to the equation, it completely breaks.
The Standard Model Quarks Leptons & Neutrinos Higgs: • Peter Higgs came up with a way to fix this: He added a new part to the equation of the standard model that allowed all the particles to have mass and still allowed the equation to work • But if nature worked the way Higgs predicted, there would also be a new particle in the Standard Model– The Higgs Boson!
The Standard Model Quarks Peter Higgs Leptons & Neutrinos Higgs: • Peter Higgs came up with a way to fix this: He added a new part to the equation of the standard model that allowed all the particles to have mass and still allowed the equation to work • But if nature worked the way Higgs predicted, there would also be a new particle in the Standard Model– The Higgs Boson!
How Do We Look for the Higgs Boson?
How do we look for the Higgs Boson? H W W H Z The Higgs only lasts for a fraction of a second. We look for the particles the Higgs decays to. H τ Z H γ γ τ H b b
How do we look for the Higgs Boson? H W W H Z The Higgs only lasts for a fraction of a second. We look for the particles the Higgs decays to. H τ Z H γ γ τ H Bosons b b
How do we look for the Higgs Boson? H W W H Z The Higgs only lasts for a fraction of a second. We look for the particles the Higgs decays to. H τ Z H γ γ τ H Fermions b b
Looking for the Higgs Boson Mass of two photons Z ll Mass of two Z’s
ATLAS and CMS looked for a new particle decaying the way the Higgs would. Adding together decays from Photons, Z’s and W’s Evidence was seen July 4, 2012
The first evidence of the Higgs was in Bosonic decays H W W H Z H τ Z H γ γ τ H Bosons b b
In November we saw the first evidence of Fermionic decay H τ τ H Fermions b b Further evidence that this is the Standard Model Higgs and not some other particle
Higgs -> Tau • The distribution of particles decaying to two taus. Solid colors are backgrounds, red line is signal.
- Slides: 14
