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6.1.3 Standard Model. The Theory of (Almost) Everything. Definition. A theory that describes three of the four fundamental forces of nature and the various particles that make up matter in the Universe. This theory is consistent with Relativity and Quantum Mechanics. Classes of Matter.
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6.1.3 Standard Model The Theory of (Almost) Everything
Definition • A theory that describes three of the four fundamental forces of nature and the various particles that make up matter in the Universe. This theory is consistent with Relativity and Quantum Mechanics.
Classes of Matter Matter • Made up of PARTICLES and their ANTIPARTICLES with EQUAL mass and OPPOSITE charge. Hadrons Leptons Do not experience the strong force tau (τ-) muon (μ-) electron (e-) τ neutrino (ντ0) μ neutrino (νμ0) e neutrino (νe0) Anti-Leptons anti-tau (τ̄+) anti-muon (μ̄+) anti-electron (ē+) anti-τ neutrino (ν̄τ0) anti-μ neutrino (ν̄μ0) anti-e neutrino (ν̄e0) Baryons any 3 quarks Anti-Baryons any 3 anti-quarks Mesons any quark plus any anti-quark Quarks Anti-Quarks
Example #1 • What charges are allowed for mesons? quark (+2/3e or -1/3e) plus anti-quark (-2/3e or +1/3e) +1e, 0, -1e
Example #2 • Give an example of a baryon with a +1e charge. ex. uud, ttb, ccs
Example #3 • What is the charge on an anti-tau particle? tau = -1e anti-tau = +1e
Example #4 • A charged kaon (K+) is composed of an up quark and an anti-strange quark. • What is the charge on this type of kaon? up = +2/3e anti-strange = +1/3e +1e
Beta Decay • A neutron will spontaneously decay into a proton, electron, and anti-electron neutrino. - udd uud (one down quark becomes an up quark) - charge is conserved - mass of neutron > mass of proton