2.1 The particle zoo

Question 1

What are cosmic rays?

Answer 1

» High energy particles that travel through space from the starts including the sun

Question 2

What happens when cosmic rays enter the earth’s atmosphere?

Answer 2

» Create new short-lived particles and antiparticles

Question 3

What is a muon?

Answer 3

» A heavy electron which is negatively charged
» Has a rest mass over 200 times the rest mass of an electron

Question 4

What is a pion?

Answer 4

» Pie meson which is positively charged, neutral, or negatively charged

Question 5

What is a kaon?

Answer 5

» K meson can be negative, neutral or positvely charged

Question 6

How are kaons produced?

Answer 6

» Produced in 2s through the strong interaction

Question 7

Why are kaons known as strange particles?

Answer 7

» Decay took longer than expected
» Included pions as the products

Question 8

Why must kaons decay via the weak interaction?

Answer 8

» As the quark flavour changes, the quark flavour cannot change in strong interaction

Question 9

What can kaons decay into?

Answer 9

» Pions
» Muons
» Antineutrino

Question 10

What can a pion decay into?

Answer 10

» Muon, an antineutrino
» Antimuon and neutrino

Question 11

What can pion +0 decay into?

Answer 11

» High - energy photons

Question 12

What can Muons decay into?

Answer 12

» Electron and antineutrino

Question 13

What can an antimuon decay into?

Answer 13

» Positron and a neutrino