Up Learn – A Level physics (AQA) – THE ATOM AND BEYOND
Lepton Number
What do we mean by lepton number and why is it useful?
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The Atom and Beyond
2. The Constituents of the Atom (free trial)
3. The Nucleus (free trial)
4. Electrons in The Bohr-Rutherford Model – Article (free trial)
5. The Mass of The Electron (free trial)
6. The Mass of The Nucleons (free trial)
7. The Charge of Particles (free trial)
8. Relative Charge (free trial)
9. Proton Number (free trial)
10. Proton Number Notation (free trial)
11. 118 Elements in the Periodic Table – Article (free trial)
12. Ions (free trial)
13. Ions and Relative Charge (free trial)
14. Charge Notation (free trial)
15. Special Cases of Charge Notation (free trial)
16. Isotopes (free trial)
17. Nucleon Number (free trial)
18. Nucleon Number Notation (free trial)
19. AZX Notation (free trial)
20. Calculating The Neutron Number – Article (free trial)
2. Qwarks and Qworks (free trial)
3. Protons and Quarks (free trial)
4. Fundamental Particles (free trial)
5. The Up Quark (free trial)
6. The Down Quark (free trial)
7. How Do We Know Quark Charges? – Article (free trial)
8. Protons, Neutrons, Quarks and Relative Charge (free trial)
9. The Strange Quark (free trial)
10. Baryons
11. Quarks and Baryon Number (free trial)
12. Quarks and Strangeness (free trial)
13. Properties of Quarks – Article (free trial)
14. Other Quarks – Article (free trial)
2. Electrons and Leptons (free trial)
3. The Discovery of The Muon (free trial)
4. The Muon: Charge and Symbol (free trial)
5. Neutrinos (free trial)
6. Neutrino Flavours and Symbols (free trial)
7. Neutrino Charge and Mass (free trial)
8. Lepton Number
9. The Tau – Article (free trial)
2. The History of Antiparticles – Article (free trial)
3. Fundamental Particles and Their Antiparticles (free trial)
4. Quantum Numbers (free trial)
5. Antiparticles and Quantum Numbers (free trial)
6. Antiparticle Mass – Article (free trial)
7. Naming Antiparticles (free trial)
8. Antiparticle Symbols (free trial)
9. Antihydrogen (free trial)
10. Where’s all the antimatter? – Article (free trial)
2. The Four Fundamental Forces (free trial)
3. The Electromagnetic Force (free trial)
4. Gravity (free trial)
5. The Strong Nuclear Force: Basics (free trial)
6. The Strong Nuclear Force: Range (free trial)
7. The Strong Nuclear Force: Range Diagram (free trial)
8. The Weak Nuclear Force: Basics (free trial)
9. Particles and Forces (free trial)
10. Exchange Particles and Fundamental Bosons – Article (free trial)
11. Exchange Particles and the Weak Nuclear Force
12. Exchange Particles and the Electromagnetic Force (free trial)
13. Exchange Particles and the Strong Nuclear Force (free trial)
14. Exchange Particles – Article (free trial)
2. Hadrons (free trial)
3. Baryons – Article (free trial)
4. Baryons and Antibaryons (free trial)
5. Other Baryons – Article (free trial)
6. Mesons (free trial)
7. The Pion – Article (free trial)
8. Pion Composition (free trial)
9. Pion Charge (free trial)
10. Pion Name and Symbol (free trial)
11. The Kaon (free trial)
12. Kaon Charge (free trial)
13. Kaon Name and Symbol (free trial)
14. Stable Hadrons (free trial)
15. Identifying Hadron Composition – Worked Example (free trial)
So far, we’ve seen three quarks.
And, we’ve seen the names, symbols and charges of these quarks.
Next, there are two more properties that we need to look at.
The first of these is baryon number.
And, to find out what that is… we need to start by looking at what a baryon is.
For instance, a proton is made up of three quarks… so it is a baryon.
Next… a neutron is also made up of three quarks… so, it is also a baryon.
When a particle is made up of three quarks… we call it a baryon.
Next, a baryon has a property called a baryon number.
Where all baryons have a baryon number of plus one
For example, a proton has a baryon number of plus one.
And so, a neutron has a baryon number of…
A neutron has a baryon number of plus one.
And we know that because…
A neutron is a baryon since it’s made up of three quarks.
And, all baryons have a baryon number of +1.
Finally, why do we have baryon numbers? What’s the point of them?
Well, baryon numbers help us to understand what’s happening during particle interactions.
For instance, when we smash protons together at the Large Hadron Collider in Cern.
For now, we’re not going to look at these interactions.
And so we’re not going to look more at the baryon number … right now…
…but we will dive into the baryon number more in the particle interactions section of the course.
To sum up…
Baryon is the name we give for particles made up of three quarks.
A baryon has a baryon number of plus one.