7. Particles and nuclear structure

Question 1

Ur best bet lowkey is first lesson.

It wasn’t after all, it was the whole 15 days D:

Answer 1

Ye ik, i don’t have time….

^^^ what he said

Question 2

Know matter and antimatter

Answer 2

Mk

U know, i actually totally forgot about that anyway :P

Question 3

Tell me about fundamental particles

Answer 3

Scientists made basic structure of an atom:
consisted of heavy nucleus made of protons and neutrons surrounded by electrons in different energy levels

Three types of forces matching the 3 particles:
gravitational force between masses, electromagnetic forces between the charges and the strong force acting between nucleons

Then some dude tried to find another particle - a particles identical to the electron but with a positive charge. Summin bout a theory that anti-electrons called positrons had to exist

Course Carl detected “positrons” in cosmic radiation so ye ig they do exist. And as theory for neutrons being developed as a fundamental particle, new discoveries were undermining it. (The neutron was not the original building block)

What constituted a fundamental particle?:
Something that cannot be broken down into smaller parts

Question 4

What are fundamental particles made out of?

Answer 4

Particles are made up of 2 things:
- Light leptons (light particles, no feel strong force)
- Heavy hadrons (heavy particles, feel strong force, made of quarks)
Now we look within

Question 5

Show me the whole particles classification system

Answer 5

Leptons
Consists of 3 particles:
- Electron (fundamental?)
- Neutrino
- Others

Hadrons
Consists of 2 particles:
- Mesons (made of 2 quarks)
- Baryons (made of 3 quarks)
Baryons
Consists of 2 other particles:
- Proton (uud)
- Neutron (udd)
Mesons
Consists of 3 other particles:
- π⁺ = +1 charge
- π⁰ = 0 charge
- π^- = -1 charge

Question 6

What consists of Baryons?
rq bout their quark number?

Answer 6

Proton and Neutron
They each 3 quarks

Question 7

What consists of Mesons?
rq bout their quark number?

Answer 7

Pions:
- π⁺
- π⁰
- π^-
They each have 2 quarks

Question 8

Tell me all about matter and antimatter

Answer 8

Ever since positron discovery, antiparticles been observed & detected for all known particles
But tbh, we just know it’s the exact opposite type shiii

Particles & anti with its mass & charge
Proton = 1.673 x 10^-27 = +1e
Antiproton = 1.673 x 10^-27 = -1e

Neutron = 1.675 x 10 ^-27 = 0
Antineutron = 1.675 x 10^-27 = 0

Electron = 9.11 x 10^-31 = -1e
Positron = 9.11 x 10^-31 = +1e

Neutrino = 0 = 0
Antineutrino = 0 = 0

Most importantly tho, the charge is important here

Question 9

What are these quark particles?

Answer 9

We have quark particles:
u = +2/3
d = -1/3
ū = -2/3
đ = 1/3 (not the correct letter btw, literally gotta be the same as ū)
GIVEN IN DATA BOOKLET

Then we have to state what the other particles are made out of from these quarks.
In addition, only baryons and mesons are made up of quarks.

Question 10

What quarks are proton made of?
And baryon charge?

Answer 10

uud
+2/3 + +2/3 + -1/3 = -1

Question 11

What quarks are neutron made of?
And baryon charge?

Answer 11

udd
+2/3 + -1/3 + -1/3 = 0

Question 12

What quarks are antiproton made of?
And baryon charge?

Answer 12

ūūđ
-2/3 + -2/3 + +1/3 = -1

Question 13

What quarks are antineutron made of?
And baryon charge?

Answer 13

ūđđ
-2/3 + +1/3 + +1/3 = 0

Question 14

What quarks are π⁺ made of?
And baryon charge?

Answer 14

uđ
+2/3 + +1/3 = 1

Question 15

What quarks are π⁰ made of?
And baryon charge?

Answer 15

uū/dđ
+2/3 + -2/3 OR -1/3 + +1/3 = 0

Question 16

What quarks are π^- made of?
And baryon charge?

Answer 16

dū
-1/3 + -2/3 = -1

Question 17

How does π⁰ have a much shorter lifetime than the other two pions?

Answer 17

It can annihilate itself by electro magnetics

Question 18

What’s the jig with leptons?

Answer 18

Ones that don’t have quarks
It’s only their own lepton number lol
Leptons:
Electron e^{-</sub>= +1
Neutrino v_ε = +1
Antielectron e₊ = -1
Antineutrino v_ε = -1
^ the equivalent to line above type shi}

Question 19

What are the 4 forces of nature?

Answer 19

There are 4 types of forces of nature: Electromagnetic, Strong, Weak, Gravity

• Electromagnetic forces are due to the exchange of photons
• Strong forces are due to the exchange of gluons
• Weak forces are due to the exchange of W and Z particles
• Gravity forces are theorized to be the exchange of gravitons

Question 20

In-depth detail of gravity force?

Answer 20

Gravity force (all particles)
- Force that keeps the Earth in orbit around the Sun
- Controls the movement of stars and planets
- Extremely weak and can be ignored
- Unless masses of objects involved are extremely large
- So we can ignore it for particle interactions

Question 21

In-depth detail of electromagnetic force?

Answer 21

Electromagnetic force (all charged particles):
- Relatively strong
- Governs interactions composed entirely of charged particles and photons
- Neutral hadrons will experience this force as they contain charged quarks
- Strength of force = likeliness interaction will occur
- Lifetime decays associated will be shorter

Question 22

In-depth detail of strong force?

Answer 22

Strong force (quarks):
- The strongest interaction
- Only experienced by quarks and particles composed of hadron quarks
- Responsible for the production of new particles from nucleon-nucleon interactions

Question 23

In-depth detail of weak force?

Answer 23

Weak force (all particles):
- Much weaker than strong & electromagnetic force
- Only significant in cases where them 2 forces don’t operate
- Weak nature of force reduces probability of the interaction occurring leading to long lifetime decays
- Interactions where neutrinos are involved or quarks change flavour can only take place via weak force

Question 24

Whole summary on 4 forces of nature?

Answer 24

Strongest to weakest = affected = range = key points?:
Strong g = Hadrons, Quarks, Gluons = diameter of nucleus = Attractive or repulsive based on distance
Electromagnetic y? = Things with charge = infinity range = Attractive for unlike charge, Repulsive for like charge
Weak W/Ƶ = Quarks and leptons = 0.1% proton diameter = Can attract/repel different mechanism
Gravity “graviton” = Anything with mass = infinity range = Only attractive

And apparently more recently, weak and electromagnetic force have been unified into the electroweak force

Question 25

Summarise how to do decays and conservations?

Answer 25

Decays:
2 types you’ll be asked:
Beta decay β - it’s an electron and would increase the “atomic number”
Alpha decay α - a “helium”, decrease in mass by 4 and decrease in atomic number by 2 (the atomic number more imp than the mass)
In addition to this, there’ll obviously be the anti version too, so u’d have to do the reverse

Conservations:
So for this one, there’ll be 3 laws to be aware of:
charge, baryons and leptons
You’d be told about their numbers in the data booklet however, be very very aware about the anti stuff
You practically gotta remember how many u’s and d’s protons and neutrons and the mesons have since that’s probably the stuff u’d needa learn