Particles

Question 1

What is one particle not effected by the weak interaction?

Answer 1

Photon

Question 2

What is not conserved in weak interactions like beta decay and electron capture?

Answer 2

Strangeness is not conserved.

Question 3

What is a Muon and what type of particle is a µ+?

Answer 3

A moun is a class of lepton which is like a heavier electron (200x heavier), And a µ+ is a antiparticle.

Question 4

Quark structure of a baryon?

Answer 4

3 quarks held together by the strong force.

Question 5

Quark Structure of a Meson

Answer 5

A Quark Anti-Quark Pair.

Question 6

Quark structure of an antibaryon?

Answer 6

Consists of 3 anti-quarks.

Question 7

Name one similarity and one difference between a particle and its respective antiparticle?

Answer 7

Similarity - Same Mass

Difference - Charge, Lepton# and Baryon#

Question 8

Give one characteristic of a strange particle that makes it different from a particle that is not strange

Answer 8

• Contains a Strange Quark

which means it has a longer half life than expected

Question 9

What do Kaons Decay into?

Answer 9

Pions

Question 10

What are bosons?

Answer 10

They are exchange particles for forces/interactions.

Question 11

Name the bosons for each force/interaction:

• Weak Nuclear
• Strong Nuclear
• Electromagnetic
• Gravitational

Answer 11

Weak: W+,W-,Z°
Strong: Pions (gluon is outside of spec)
Electromagnetic: (Virtual) Photon
Gravitational: Graviton

Question 12

When is Strangeness not conserved?

Answer 12

During Weak Nuclear Interaction.

Question 13

Where does the strong force act and what is it’s ranges?

Answer 13

Acts between nucleons to keep nucleus together.
0-0.5fm: Largely Repulsive
0.5-3fm: Attractive
3fm and onwards: Negligible

Question 14

How does Strong Nuclear Force keep the nucleus stable?

Answer 14

Strong force is attractive between 0.5-3fm which helps mitigate repulsive electromagnetic force. But stops nucleus imploding due to it being repulsive between 0-0.5fm. Therefore keeps each nucleon at a stable distance from one another.

Question 15

What does the Weak Interaction cause?

and give some examples

Answer 15

Decay/Change in Quarks.
Beta +/-
Electron Capture

Question 16

What is the order of strength of the fundamental forces?

Answer 16

1) the strong nuclear force,
2) the electromagnetic force,
3) the weak nuclear force,
4) gravity,

Question 17

What are the two sub groups of hadrons?

Answer 17

Baryons (3 quarks), Mesons (quark + antiquark pair)

Question 18

What are the two mesons you need to know how to find the quark structure of and how to do it?

Answer 18

Pions and Kaons:
All mesons are a quark anti quark pair so keep that in mind when using the formula book to equivalate charge (and strangeness for kaons)

Question 19

What property defines/differentiates Hadrons and Leptons?

Answer 19

Hadrons are effected by the strong force where as Leptons are not.

Question 20

What is Annihilation and when does it occur?

Answer 20

when a particle and its antiparticle colliding and are converted into energy. The energy is released in two photons to conserve to momentum.