FERMIONS (Particles) A. Quarks 1. Types a. Up 1. Has 2/3 of a Unit of Positive Electric Charge 2. Has a Strangeness of 0 b. Down 1. Has 1/3 of a Unit of Negative Electric Charge 2. Has a Strangeness of 0 3. Up and Down are Lightest quarks c. Charm 1. Has 2/3 of a Unit of Postive Electric Charge 2. Has a Strangeness of 0 d. Strange 1. Has 1/3 of a Unit of Negative Electric Charge 2. Has a Strangeness of -1 e. Top (Truth) 1. Essential to the Electroweak Theory f. Beauty 2. Make up Neutrons, Protons, Hadrons a. Neutron is made of 2 Down Quarks and 1 Up Quark 1. Will decay if not bound within the atom 2. Can decay into a proton, electron and neutrino b. Proton is made of 2 Up Quarks and 1 Down Quark 1. Decay may occur but because of theoretical length of lifetime (approx 10^30) it may be difficult to observe 2. One possible decay is from proton into positron and 2 neutrinos 3. 32 theoretical decay modes for a proton c. Nucleons 1. Neutrons and Protons 2. Dark matter is not made of Nucleons d. Hadrons 1. Made of Quarks 2. Include protons, neutrons and pions e. Pions 1. Also known as the pi meson 2. Types a. Pi Zero 1. mass = 264 (electron) 2. electric charge = 0 3. mean lifetime: 0.9 x 10^-16 sec b. Pi Plus 1. mass = 273 (electron) 2. electric charge = positive 3. mean lifetime: 2.6 x 10^-8 sec 3. Lightest member of the meson family f. Mesons 1. Any of several subatomic particles having integral spins and masses generally intermediate between leptons and baryons 2. Types a. 3 Pi-mesons b. 4 K -mesons 1. K meson made of down, strange, antidown and antistrange 2. K^o meson made of down and antistrange quarks 3. anti-K^o made of strange, antidown quarks c. B meson 1. consist of either down and antibottom or bottom and antidown quarks 2. mass = 10 (K mesons) 3. Bind nucleons to one another 4. Made of mixture of quarks and antiquarks 5. Lose energy slowly when they pass thru matter g. Baryons 1. Any of a family of subatomic particles including nucleon and hyperon multiplets that participate in strong interactions, have half integral spins, and are generally more massive than mesons. 2. Types a. Proton, Antiproton b. Neutron, AntiNeutron c. 2 Lambda Particles d. 6 Sigma Particles e. 4 xi particles 3. All Baryons are made of 3 Quarks h. Hyperon 1. Subatomic particle 2. Characteristics a. Mass greater than the nucleon b. Can decay inot a nucleon or another hyperon and lighter particles c. Has 2I + 1 Charge States 1. I = isospin of particle multiplet e. Memos 1. Theoretical particle would be made mostly of hyperons 3. Quarks cannot exist in an unbound state B. Leptons 1. Types a. Electron 1. Lightest Charged Lepton 2. Doesn't decay for it if did it would violate the law of charge conservation since it is the lightest charged lepton b. Muon 1. mass = 207 electron rest masses c. Tau d. Electron-Neutrino e. Muon-Neutrino f. Tau-Neutrino g. All these have antimatter counterparts 2. Leptons are always less massive than quarks 3. In every pair of leptons the neutrino is always the less massive particle 4. Neutrinos dont engage in electromagnetic or strong interactions, they interact with matter only through weak forces C. Fermion Characteristics 1. Spin = 1/2 2. Angular Momentum = 1/2 h a. h = planck unit of action (10^-27 erg/sec) F. Families 1. Up and Down Quarks, Electron and Electron-Neutrino a. Make up ordinary matter 2. Charm and Strange Quarks, Muon and Muon-Neutrino 3. Top and Bottom Quarks, Tau and Tau-Neutrino a. No members of 2 and 3 are stable, with the possible exception of the neutrino Gauge Bosons (Carries of force) 1. Types A. Photon 1. Electromagnetic Force 2. Couples electric charge B. Graviton 1. Gravitational Force 2. Carries Gravitational Force C. Gluons 1. Carry Strong Force 2. Couples Quarks 3. 8 Types of Gluons 4. Exchange of gluons bind together quarks D. Intermediate Vector Bosons 1. Carry Weak Nuclear Force a. Weak Nuclear Force responsible for certain nuclear decays 2. Examples a. W^+ b. W^- c. Z^o 1. electrically neutral 2. Can decay into pairs of neutrinos and anti-neutrinos 2. Gauge Boson characteristics 1. Spin = 1 2. Angular Momentum = 1 h Quantum Chromodynamics Explains the strong force by which quarks interact on the basis of their "color". "Color" is an invisible trait that characterizes the force similar to "charge" in electricdynamics. Electrodynamic charge has one state; either positive or negative. Quarks have 3 colors. Quarks: red, green, blue. Antiquarks: antired, antigreen, and antiblue. Electroweak Theory Unites electromagnetism and weak interactions. Predicted the neutral weak interaction and the heavy intermediate bosons, W^+, W^-, Z^o Advantages: Requires fermions come in pairs. ie - electron, electron-neutrino Each particle must have an antiparticle ie - electron, positron ie - electron-neutrino, electron-antineutrino Disadvantages: Doesn't specify how many pairs make a family. Doesn't specify about the number of families of matter Higgs Particle Particle which in theory should be able to explain the origin of particle mass. Kaons Hyperons both are antistrange elementary particles Laws of Conservation Charge Translational momentum Angular Momentum (Spin) Energy Strangeness Parity Creating Z Particles Produced by electron-positron pair whose combined kinetic energy make up the difference between their rest masses (expressed in equivalent energy) and the rest mass of Z. Z can decay into "channels". Each decay channel shortens the life of Z. Known channels Decays to particle and antiparticle pairs of all fermions with less than 1/2 the Z mass 3 varities of charged leptons 5 kinds of quarks 3 varities of neutrinos Electroweak theory predicts the contributions to channels to an accuracy of 1% for each: combined quark channels 1.74 eV charged lepton channel 83.5 million eV neutrino channel 166 million ev Electron-Positron Annihilations 1. 88% produce quark and anti-quark 2. 12% divided equally among the production of: tau lepton and antitau lepton muon and antimuon and electron-positron (reverses the initial annihilation) Unanswered Questions: 1. Why are there just 3 families of particles 2. What law determines the masses of their members, decreeing that they span 10 powers of 10