Particle Physics

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Hadrons

Experience the strong nuclear force, weak nuclear force, gravity and, if charged, electromagnetic force.

All have rest mass

Proton is stable, but all other hadrons decay through weak nuclear force

Comprised of quarks

Divided into Baryons and Mesons:

Baryons - include protons, neutrons and sigma particles, made up of 3 quarks

Mesons - include Kaons and Pions, made up of a quark and an antiquark

K mesons decay into pi mesons, muons and antineutrinos, and anti muons and neutrinos

Charged pi mesons decay into muons and antineutrinos, or antimuons and neutrinos

Pi 0 meson decays into high energy photons

Leptons

Experience weak nuclear force, gravity and, if charged, electromagnetic force.

All have rest mass

Fundamental particles

Include electrons, neutrinos and muons

Forces and Exchange Particles

Strong nuclear force:

acts between Hadrons

Gluons between quarks as exchange particles

Pions between Baryons as exchange particles

has a range of 3-4fm

repulsive up to 0.5fm, then attractive between 0.5-4fm

strangeness always conserved

Weak nuclear force:

acts between all particles

W+, W- and Z0 bosons as exchange particles

responsible for alpha and beta decay, and changes to strangeness of +/-1

Electromagnetic interaction:

acts between charged particles

virtual photons as exchange particles

Gravitational interaction:

acts between all particles with mass

gravitons as exchange particles