hadron: a particle that is affected by the strong nuclear force. consists of baryons and mesons.
baryons: a hadron made up of three quarks, like protons and neutrons, and antiprotons and antineutrons.
meson: a hadron made up of a quark and an antiquark, like pions and kaons, and antipions and antikaons.
all baryons except the proton are unstable so all baryons decay into a proton.
baryon number: the number of baryons in a particle.
the proton and neutron and all other baryons have a baryon number of B=+1.
antibaryons have a baryon number of B=-1
all other particles that aren't baryons have a baryon number of B=0.
mesons are pions and kaons. all mesons are unstable and have a baryon number of B=0.
mesons interact with baryons via the strong force.
pions are the lightest mesons. there are three versions of the pion. PIE+, PIE0 and PIE-.
kaons are the heavy and more unstable mesons, they exist as K+, K0 and K-.
hadrons feel the strong force, while leptons can only interact via the weak force/interaction.
and their respective neutrinos.
lepton number: the number of leptons in a particle. count seperately for different types of leptons.
electrons have an electron lepton number of +1
muons have a muon lepton number of +1
their respective neutrinos have the same lapton numbers.
conservation of lepton and baryon numbers
both Baryon and both types of lepton number need to be conserved for a particle interaction to happen.
to check this just work out the numbers on each side of the reaction.