5.3.2 Fundamental Particles. (a) explain that since protons and neutrons contain charged constituents called quarks they are, therefore, not fundamental particles. Fundamental particles. Until mid-20 th century, it was though that all atoms consisted of electrons, protons and neutrons
CERN Standard model
(b) describe a simple quark model of hadrons in terms of up, down and strange quarks and their respective antiquarks, taking into account their charge, baryon number and strangeness;
Not affected by the strong nuclear force
Affected by the strong nuclear force
u d d
u u d
(i) state that a β- particle is an electron and a β+particle is a positron
(h) state that (electron) neutrinos and electron) antineutrinos are produced during β+ and β-decays, respectively
In β- decay a neutron is changed into a proton, in other words uddchanges into uud. A d changing to a u can only happen through the weak interaction.
In β+ decay a proton is changed into a neutron, in other words uudchanges into udd. A u changing to a d can only happen through the weak interaction.