Fundamental particles are not composed of any other kinds of particles.
Everything in our nature is made of these particles; Whatever is happening now can be reduced to matter particles (fermions) exchanging force carrier particles (Bosons).
For instance; We don't pass through the floor (or chair or desk or wall or anything solid) is due to Pauli Exclusion principle which states that no two fermions can be in same state. So fermions (which are electrons in our outer skin and electrons of floor or any other solid object) repel. For your information the electrons in our skin and electrons in any non living structure are exactly identical and same applies to all other fundamental particles. We can also explain the same using Coulomb law of electrostatics : Two electrons will repel and repulsion becomes 4 times if their distance is halved.
Fermions are also known as matter particles. These particles are what we and all of this universe is made up of (except space-time). These particles obey Fermi Dirac Statistics.
These particles are identified by their half integer spin (\({\frac{1}{2},\frac{3}{2},\frac{5}{2},\frac{7}{2}, ....}\))
Fermions can further be classified into
- Leptons (\({e^{-},\mu^{-},\tau^{-},\nu _{e},\nu _{\mu },\nu_{\tau}}\))
- Quarks (u,d,c,s,t,b)
We generally call Leptons and Quarks as spinors since they are spin \({\frac{1}{2}}\) particles.
These particles are also known as mediators or messengers or force carrier particles. We call them bosons since these particles have integer spin quantum number (J=\(0,1,2,3,4 ...\)) and obey Bose Statistics.
Example: photons (exchanged between two electrons or same charge particles)
When two particles are interacting (attracting or repelling); these force carrier particles are exchanged which kind of carries information of "come closer" or "Go away".
Well the behaviour of these fundamental particles is dramatic; they exchange different kinds of messenger particles to behave differently. On the basis of different mediators (or messengers) the interaction is different (strong of weak).
On the basis of mediators we have the following theories to describe their behaviour.
Force | Strength | Theory | Mediator | Between |
---|---|---|---|---|
Strong | 10 | Quantum Chromodynamics | Gluons | Quarks |
Electromagnetic | \({10^{-2}}\) | Quantum Electrodynamics | Photon | All Charged Particles |
Weak | \({10^{-13}}\) | Flavour Dynamics | \(W^{\pm},Z^0\) | All particles |
Gravitation | \(10^{-42}\) | Geometrodynamics | graviton | All massive particles |