7. Particles and nuclear structure Flashcards
Ur best bet lowkey is first lesson.
It wasn’t after all, it was the whole 15 days D:
Ye ik, i don’t have time….
^^^ what he said
Know matter and antimatter
Mk
U know, i actually totally forgot about that anyway :P
Tell me about fundamental particles
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
What are fundamental particles made out of?
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
Show me the whole particles classification system
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
What consists of Baryons?
rq bout their quark number?
Proton and Neutron
They each 3 quarks
What consists of Mesons?
rq bout their quark number?
Pions:
- π+
- π0
- π-
They each have 2 quarks
Tell me all about matter and antimatter
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
What are these quark particles?
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.
What quarks are proton made of?
And baryon charge?
uud
+2/3 + +2/3 + -1/3 = -1
What quarks are neutron made of?
And baryon charge?
udd
+2/3 + -1/3 + -1/3 = 0
What quarks are antiproton made of?
And baryon charge?
ūūđ
-2/3 + -2/3 + +1/3 = -1
What quarks are antineutron made of?
And baryon charge?
ūđđ
-2/3 + +1/3 + +1/3 = 0
What quarks are π+ made of?
And baryon charge?
uđ
+2/3 + +1/3 = 1
What quarks are π0 made of?
And baryon charge?
uū/dđ
+2/3 + -2/3 OR -1/3 + +1/3 = 0
What quarks are π- made of?
And baryon charge?
dū
-1/3 + -2/3 = -1
How does π0 have a much shorter lifetime than the other two pions?
It can annihilate itself by electro magnetics
What’s the jig with leptons?
Ones that don’t have quarks
It’s only their own lepton number lol
Leptons:
Electron e-</sub>= +1
Neutrino vε = +1
Antielectron e+ = -1
Antineutrino vε = -1
^ the equivalent to line above type shi
What are the 4 forces of nature?
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
In-depth detail of gravity force?
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
In-depth detail of electromagnetic force?
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
In-depth detail of strong force?
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
In-depth detail of weak force?
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
Whole summary on 4 forces of nature?
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
