What is the Higgs and How do we
- Slides: 13
What is the Higgs 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 is missing one large piece: • Why aren’t all particles massless like Light? Why do some particles have mass?
The Standard Model is missing one large piece: • Why aren’t all particles massless like Light? Why do some particles have mass? Peter Higgs
1964 • Peter Higgs and others came up with a way to add to the equations of the Standard Model such that they still accurately described particle interactions but ALSO described how some particles become Massive. This additional part of the SM would become known as the Higgs Mechanism. if μ 2 is negative, the potential looks like this where the minimum energy state is non-0. If the Higgs Mechanism was correct, there would also be an associated Higgs Boson. So to prove theory was correct we needed to find 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.