Chapter 2.8 Particle physics - Summary Edexcel A Level Physics Student Book 2 - Physics (9PH0)

2.8 - Particle physics
Matter and antimatter
● ***Antimatter: same mass as ordinary matter but having opposite electric charges
● When matter and antimatter collide, they annihilate each other and are converted
back into energy




+¿ →γ + γ ¿
1. e−¿+e ¿
(at low energies)
−¿+ν +u +d +b+b ¿
2. u+u → e e




Electronvolt and mass
● Charge: 1 e = 1.6 x 10-19 C
● Energy: ∵ E = QV, ∴ E = (1.6 x 10-19) x 1, 1 eV = 1.6 x 10-19 J
● Mass: ∵ E = mc2, ∴ m = (1.6 x 10-19) ÷ (3 x 108)2, 1 eV c-2 = 1.7^ x 10-36 kg
○ True value: 1.782661845 x 10-36 kg


Standard model (quark-lepton model)
● Fundamental particles

6 flavours Up quark Down quark Charm quark Strange quark Top Bottom quark
of quarks (u) (d) (c) (s) quark (t) (b)

Charge +2 −1 +2 −1 +2 −1
e e e e e e
3 3 3 3 3 3



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