Particle Physics

Question 1

What are the two main types of fundamental particles?

Answer 1

quarks and leptons

Question 2

What are the two families of hadrons

Answer 2

Baryons and Mesons

Question 3

What are hadrons?

Answer 3

Particles made of quarks, including baryons (3 quarks) and mesons (quark-antiquark pairs).

Question 4

Name two baryons.

Answer 4

Proton and neutron.

Question 5

Name two mesons.

Answer 5

Pion (π) and kaon (K).

Question 6

What are leptons?

Answer 6

Fundamental particles that do not experience the strong nuclear force, e.g., electrons, neutrinos, and muons.

Question 7

What is the quark structure of a proton?

Answer 7

uud (up-up-down).

Question 8

What is the quark structure of a neutron?

Answer 8

udd (up-down-down).

Question 9

What are the four fundamental forces?

Answer 9

Strong nuclear, electromagnetic, weak nuclear, gravity.

Question 10

Which force acts between quarks?

Answer 10

Strong nuclear force, mediated by gluons.

Question 11

What is the exchange particle of the electromagnetic force?

Answer 11

virtual Photon (γ).

Question 12

What is the exchange particle of the weak force?

Answer 12

W+, W- bosons.

Question 13

Which force is responsible for beta decay?

Answer 13

Weak nuclear force.

Question 14

Which force has an infinite range?

Answer 14

Electromagnetic and gravity (strong and weak forces have short ranges).

Question 15

What are the four key conservation laws in particle interactions?

Answer 15

Charge, baryon number, energy-momentum.

Question 16

Is strangeness always conserved?

Answer 16

No, it is conserved in strong interactions but not in weak interactions.

Question 17

What is the baryon number of a proton?

Answer 17

+1.

Question 18

What is the baryon number of a neutron?

Answer 18

+1.

Question 19

What is the baryon number of an electron?

Answer 19

0 (only hadrons have a baryon number).

Question 20

What is the lepton number of an electron?

Answer 20

+1.

Question 21

What is the lepton number of an electron neutrino?

Answer 21

+1.

Question 22

What is the lepton number of a muon?

Answer 22

+1, but in the muon lepton family.

Question 23

What happens in beta-minus decay?

Answer 23

A neutron turns into a proton, emitting an electron and an electron antineutrino.

Question 24

Write the equation for beta-minus decay.

Answer 24

n → p + e⁻ + ν̅ₑ

Question 25

What is the exchange particle in beta-minus decay?

Answer 25

W⁻ boson.

Question 26

What happens in beta-plus decay?

Answer 26

A proton turns into a neutron, emitting a positron and an electron neutrino.

Question 27

Write the equation for beta-plus decay.

Answer 27

p → n + e⁺ + νₑ

Question 28

What is the exchange particle in beta-plus decay?

Answer 28

W⁺ boson.

Question 29

What happens in electron capture?

Answer 29

A proton absorbs an electron to become a neutron, emitting an electron neutrino.

Question 30

What happens in electron-positron annihilation?

Answer 30

An electron and positron collide, annihilating into two photons.

Question 31

What happens in pair production?

Answer 31

A high-energy photon creates an electron and positron pair.

Question 32

What are strange particles?

Answer 32

Particles that contain a strange quark, such as kaons (K⁺, K⁻, K⁰).

Question 33

How are strange particles produced?

Answer 33

Through the strong interaction, so strangeness is conserved in production.

Question 34

How do strange particles decay?

Answer 34

Via the weak interaction, so strangeness is not conserved in decay.

Question 35

What is the charge and strangeness of a K⁺ meson?

Answer 35

Charge = +1, Strangeness = +1.

Question 36

What is the charge and strangeness of a K⁰ meson?

Answer 36

Charge = 0, Strangeness = +1.