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Elementary Particles


Elementary particles are those particles which are indivisible and not made up of other particles.

Proton and neutrons       --------->    Made up of Quarks

Types of Particles

  1. On the Basis of Mass:
     a. Light-mass Particles
     b. Intermediate-mass Particles
     c. Heavy-mass Particles
  2. On the Basis of Charge:
     a. Positive Charge Particles
     b. Negative Charge Particles
     c. Neutral Particles
  3. On the Basis of Spin:
     a. Fermians - Odd Integer multiple of 1/2
     b. Bosons: Even integer multiple of 1/2 (or simply integers, 0,1,2, etc.)
  4. On the Basis of Average Life Span:
     a. Stable - Long Life
     b. Unstable - Very Short Life

Interaction Forces:
 a. Gravitational
 b. Electromagnetic
 c. Weak Nuclear Force (between leptons and hedrons)
 d. Strong Nuclear Force (between quarks)

Anti-particles: Anti-particles are particles having all properties similar except any one property w.r.to the other particle.

PropertiesFor Electron (e-)For anti-particle of electron (e+)
Mass (Smm
Charge (Different)-ve+ve
Spin (Same)ss
Average Life Span (Same)ll

Pair Production: The phenomena of conversion of energy into matter is called pair production. When energetic photon strikes the heavy nucleus, particles and it's corresponding anti-particles are produced.