3.2.1.5-7 Particle classification, Quarks and Conservation Laws

what is the pion?

the exchange particle of the strong nuclear force, a meson

what is the kaon?

a type of meson that decays into pions

what are leptons? give examples

fundamental particles that don't feel the strong nuclear force. they only really react with other particles via weak interaction e.g. electron, muon, neutrino (e- and muon types only) and antipartcies

what is strangeness?

a quantum number that reflects the fact that strange particles are always created in pairs

what does particle physics rely on?

the collaborative efforts of large teams of scientists and engineers to validate new knowledge

what are hadrons?

anything made of quarks

what are the 2 classes of hadrons?

baryons and mesons

what are baryons? give examples

made up of three quarks or three antiquarks (known as anti baryons) e.g. proton, neutron

what are mesons?

made up of a quark and an antiquark e.g. pion, kaon

what is baryon number?

the no. of baryons in an interaction - a quantum number that must be conserved

what is the only stable baryon?

the proton, which other baryons eventually decay into

what is the muon?

a particle that decays into an electron

what are strange particles?

contain strange quark they are produced through the strong interaction and decay through the weak interaction. e.g. kaons

what is strangeness in strong and weak interactions?

conservation in strong interactions
can change by 0/+1/-1 in weak

properties of quarks and antiquarks (charge, baryon no and strangeness)

what does a neutron decay into?

a proton, an e- and an anti-neutrino

Change of quark character in β+ decay

Change of quark character in β- decay

what is conserved in interactions?

energy and momentum