PHYS 1750: SELECTED TOPICS in PHYSICS
LECTURE 47. Elementary Particles and Forces
| 31.2. | Four Forces of Nature | ||
| 1. | Strong: quark-quark | ||
| a. | Nuclear; short range | ||
| b. | gluons | ||
| 2. | Electromagnetic: charge-charge | ||
| a. | atoms; long range | ||
| b. | photons | ||
| 3. | Weak: quark-lepton | ||
| a. | beta decay; short range | ||
| b. | W, Z | ||
| 4. | Gravity: mass-mass | ||
| a. | masses; long range | ||
| b. | gravitons | ||
| 31.4,5. | Elementary Particles | ||
| 1. | Hadrons: made of quarks | ||
| a. | Mesons: 2 q, example: pions | ||
| b. | Baryons: 3 q, examples: p, n | ||
| 2. | Leptons: elementary | ||
| a. | Electron, muon, tau | ||
| b. | E-, mu-, tau-neutrinos | ||
| 3. | Quarks | ||
| a. | Do not singly exist | ||
| b. | up, down, strange, charmed, bottom, top | ||
| c. | d, s, b have -1/3 charge | ||
| d. | u, c, t have +2/3 charge | ||
| e. | Example: p = uud, n = udd | ||
| f. | Color charge: R,G,B always combine to form "white" (R+G+B, R+antiR, etc) | ||
| 3. | Conservation, revisited | ||
| a. | Momentum | ||
| b. | Energy | ||
| c. | Charge | ||
| d. | Baryon | ||
| e. | Lepton | ||
| f. | Strangeness | ||
| g. | Charm | ||
| h. | Bottomness | ||
| i. | Topness | ||
| j. | Matter vs. anti-matter | ||
Review Questions for Lectures 47 and 48
Lecture 48: Cosmology