Classification Of Particles

There are many different types of particle apart from your usual ones. They only appear in cosmic rays and in particle accelerators, they decay very quicklyso they're difficult to get a handle on.

Hadrons 

• Hadrons are particles that feel the strong nulear force (or strong nuclear interaction).
• Eg, protons are positive so they need at strong force to hold them together.
• Hadrons are not fundamental particles, they are made up of smaller particles called quarks (see quark notes).
• Hadrons can be subdivided into two groups: baryons and mesons. They are lassified by the number of quarks they contain.

Baryons

• Protons and neutons are baryons.
• All baryons are unstable apart from the proton. This means they decay to become different particles.
• The particle they end up as depends on what the baryon was before it decayed, but it ALWAYS include as proton.
• Some theories predict that protons should decay with a VERY long half-life but there is no evidence for it at the moment. 
• Antiprotons and antineutrons are antibayrons.
• you don't find antibayons in ordinary matter.

Baryon Number

• The number of bayons in an interaction is called the baryon number.
• Baryons (protons and neutrons) have a baryon number of +1.
• Antibaryons (antiprotons and antineutrons) have a baryon number of -1.
• Other baryons are given…