1.7 Particles and nuclear structure

Question 1

Lepton

Answer 1

Leptons are electrons and electron-neutrinos [and analogous pairs of particles of the so-called second
and third generations].

Question 2

Hadron

Answer 2

Hadrons are particles consisting of quarks or
antiquarks bound together. Only hadrons (and quarks
or antiquarks themselves) can ‘feel’ the strong force.

Question 3

Baryon

Answer 3

A baryon is a hadron consisting of 3 quarks or 3
antiquarks. The best known baryons are the nucleons,
i.e. protons and neutrons.

Question 4

Meson

Answer 4

A meson is a hadron consisting of a quark-antiquark
pair.

Question 5

Strong interactions

Answer 5

Lifetime: 10^24s
Involve only hadrons
No change in quark flavour

Question 6

Electromagnetic interactions

Answer 6

Lifetime: 10^-12-18
Only involves charged particles (/charged components)
Photons may be emitted
No change in quark flavour

Question 7

Weak interactions

Answer 7

Lifetime 10^-10 s
Neutrinos are involved (neutral leptons)
Change in quark flavour