Particles checklist

Particles checklist

1. Mass= kg. Charge= C= A/s. Specific charge= C/kg= A/s/kg.

   • Specific charge= charge/mass
     • Specific charge- the ratio of overall charge to overall mass e.g. specific charge of an electron is 1.6E-19/1.67E-27= 9.58E7 C/kg

2. Proton number= the number of protons in one atom of an element. Nucleon number= number of protons and neutrons in one atom of an element.

3. Isotope= variations of an element with the same number of protons and electrons but a different number of neutrons

4. Strong nuclear force- keeps nucleons stable. Prevents nucleus from imploding or exploding. Repulsive at ranges < 0.5 fm and attractive at ranges < 5 fm.

5. Unstable nuclei- nucleus with dissimilar numbers of protons and neutrons.

6. Alpha decay- emission of a Helium nucleus. Proton number drops by 2, nucleon number drops by 4.

   • Beta minus Decay- neutron --> proton. Proton number increases by 1. nucleon number constant. Anti- electron neutrino required to balance lepton number. W- boson exchange particle.
     • Neutrino hypothesis- due to mass difference, another particle must make up remaining mass

7. Every particle has a corresponding anti-particle.

8. eV= divide energy in joules by 1.6E-19.

9. Annihilation- a particle and its antiparticle collides- mass converted into energy and 2 gamma ray photos of equal energy produced.

   • Pair production- photon of sufficient energy converts its energy into mass, producing a particle and its corresponding anti-particle.

10. Interactions

    • Electrostatic interaction- virtual photon exchange particle. Repulsion between electrons.
    • Strong interaction- pion carrying 'gluons' exchange particle. Ensures attraction between neutrons and protons in the nucleus.
    • Weak interaction- W+ and W- exchange particles. Massive so very short range. Allows flavour changing.
      • Beta- decay = W- boson. Beta + decay = W+ boson. Electron capture= W+ boson.
    • Gravitational interaction- graviton exchange particle.