3.2.1.5 Classification of Particles Flashcards
What is a hadron?
A hadron is a particle that feels the strong nuclear force, or interacts through the strong interaction.
Are hadrons fundamental?
Hadrons are not fundamental as they are made of quarks.
What are the two types of hadrons?
The two types of hadrons are baryons and mesons.
What are baryons?
Baryons are hadrons which are made up of three quarks.
What are the two baryons?
The two baryons are the proton and the neutron.
Which baryon is stable? What do all baryons eventually decay into?
The proton is the most stable baryon. All baryons except the proton are unstable.
All baryons except protons eventually decay into protons.
What is an antibaryons?
An antibaryon is the opposite of a baryon. For example antiprotons and antineutrons.
Why are antibaryons not found in ordinary matter?
Antibaryons are not found in ordinary matter because they are annihilated when they meet the corresponding particle.
What is the baryon number?
The baryon number is a quantum number that tells us the number of baryons.
What is the baryon number of some common particles?
The baryon number of all baryons is + 1.
The baryon number of all antibaryons is - 1.
The baryon number of all other particles is 0.
What are mesons?
Mesons are another type of hadron which are composed of a quark and an antiquark.
Are all mesons stable?
All mesons are unstable and have a baryon number of 0.
What are the two types of mesons?
The two types of mesons are kaons (symbol K) and pions (symbol pi).
What are the three types of kaon?
The three types of kaon are:
Kaon +
Kaon 0
Kaon -
What are the three types of pions?
Pion +
Pion 0
Pion -
What is the difference between kaons and pions?
Pions are lighter than mesons, whereas kaons are heaver and more unstable.
Kaons have a very short lifetime.
Kaons decay into pions.
How do mesons and baryons interact?
Mesons and baryons interact via the strong force.
What are leptons? Are they fundamental?
Leptons are particles which do not experience the nuclear strong force.
Leptons are fundamental particles.
How do leptons interact?
They only interact via the weak interaction.
What the two types of lepton?
The two types of leptons are muons and electrons.
What are the anti-leptons?
Anti-leptons are the antiparticle equivalent of leptons.
Are electrons stable, and are muons stable?
Electrons are stable and muons are heavy electrons which are unstable.
What do muons decay into?
Muons eventually decay into electrons.
What are the two types of lepton neutrino?
The electron Neutrino Ve
The muon Neutrino Vµ.
What do neutrinos have?
Neutrinos have zero mass, and zero electric charge.
What is the lepton number?
Lepton number is a quantum number which shows how many leptons a particle has.
What is the lepton number of a lepton and an anti-lepton?
Lepton number of a lepton = + 1
Lepton number of an anti-lepton = - 1
What are the two types of lepton numbers?
The two types of lepton number are muon lepton number and electron lepton number, which must be counted seperately.
What is the charge of a muon?
The charge of a muon is -1.
What are the charges of electron and muon neutrinos?
The charges on both are 0.
What is the Le number of each lepton.
Electron = + 1 Position = - 1 Electron Neutrino = + 1 Anti Electron Neutrino = - 1 All the rest have 0
What is the Lµ number of each of the leptons.
Muon = + 1 Antimuon = - 1 Muon Neutrino = + 1 Anti Muon Neutrino = -1 All the rest have 0
What is strangeness?
Strangeness is a quantum number.
Which particles are strange?
Only kaons are strange particles.
How are strange particles created and decayed?
Strange particles are created via the strong interaction, and decay via the weak interaction.
Strange particles are always produced in pairs.
What is the rule for conservation of strangeness?
Strangeness is conserved in the strong interaction, but not in the weak interaction. They can change by +/- 1 in the weak interaction.
What is the strangeness of the kaons?
K+ = +1
K0 = +1
K- = -1
Anti K0 = -1
Pions are the exchange particle for what?
Pions are the exchange particle for the strong nuclear force.
What is the definition of the strange particles?
Strange particles are particles that are produced through the strong interaction and decay through the weak interaction (eg kaons).
