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Physics
28 Nov 2025
189
4 pages
xiyu @illxiyutheretmr
Feynman diagrams are visual representations that show how particles interact with each other during collisions and decays. These... Show more
Feynman diagrams are like particle interaction maps that make complex physics much easier to understand. Think of them as comic strips showing what happens when particles bump into each other or change into different types.
These diagrams use simple rules time flows from left to right, and space runs vertically. Straight lines represent particles like protons and electrons, whilst wavy lines show force-carrying particles like photons.
Quick Tip The beauty of Feynman diagrams is that they turn complicated maths into simple pictures - perfect for visualising what's really happening in the particle world!
When protons collide with protons, they don't actually touch - instead, they exchange a photon (represented by the wavy line γ). This electromagnetic interaction is what causes the particles to repel each other.
Electron-electron collisions work exactly the same way. Two electrons approach each other, exchange a photon, then fly apart due to their negative charges repelling.
The proton-antineutrino interaction is more complex because it involves the weak nuclear force. Here, a proton transforms into a neutron by emitting a W+ boson, which then interacts with an antineutrino to produce a positron (β+).
Remember Different forces use different exchange particles - photons for electromagnetic force, W and Z bosons for weak nuclear force!
Beta decay comes in two flavours, and Feynman diagrams show exactly what's happening inside the nucleus. In β- decay, a neutron transforms into a proton by emitting a W- boson, which then decays into an electron and an antineutrino.
β+ decay (positron emission) works in reverse. A proton becomes a neutron by emitting a W+ boson, which then creates a positron and a neutrino.
The neutron-neutrino interaction demonstrates how neutrinos can occasionally interact with matter, even though they're incredibly shy particles that usually pass straight through everything.
Key Point These diagrams show that what we call "decay" is actually particles transforming through exchange of W bosons - nature's way of changing one type into another!
Electron capture happens when a proton "swallows" an electron from the atom's inner shell. The diagram shows how the electron and proton combine via a W+ boson to produce a neutron and a neutrino.
Electron-proton collisions can result in similar outcomes, where the collision energy allows the particles to interact through the weak nuclear force rather than just electromagnetic repulsion.
These interactions are crucial for understanding how stars generate energy and how certain types of radioactive materials behave in medical applications.
Pro Tip Notice how all these weak force interactions involve W bosons - they're like the universal translators that allow different particle types to interact and transform!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the mechanisms of particle interactions through exchange particles and Feynman diagrams. This summary covers key concepts such as beta decay, fundamental forces, and the role of bosons in particle physics, essential for exam preparation.
PhysicsExplore detailed notes covering essential A-Level Physics concepts, including stellar luminosity, electromagnetic radiation, nuclear decay, and gas laws. This resource is designed for AQA and other exam boards, featuring interactive flashcard-style navigation for effective revision. Access the full notes here: https://www.notion.so/Physics-Revision-AQA-A-Level-a87264d9f28c4302b.
PhysicsComprehensive revision notes on Thermal Physics, including key concepts such as phase changes, specific latent heat, the ideal gas law, and the first law of thermodynamics. Ideal for AQA A Level Physics students preparing for exams, with practice questions included to enhance understanding.
PhysicsExplore key concepts in nuclear physics, including alpha decay, gamma radiation, and the structure of the nucleus. This summary provides essential information on radioactive emissions, their properties, and implications for safety. Ideal for AQA A Level Physics revision.
PhysicsExplore key concepts in thermal physics, including internal energy, specific heat capacity, and the ideal gas law. This summary covers the relationships between temperature, pressure, and volume, as well as the kinetic theory of gases and latent heat. Ideal for A-Level physics students seeking a concise overview of essential topics.
PhysicsDive into the fundamentals of electric fields, including electric potential, forces, and their relationship with gravitational fields. This summary covers key concepts such as Coulomb's law, electric potential energy, and the behavior of charged particles in uniform fields. Ideal for students seeking a clear understanding of electrostatics.
PhysicsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
xiyu
@illxiyutheretmr
Feynman diagrams are visual representations that show how particles interact with each other during collisions and decays. These diagrams help physicists understand complex particle interactions by showing what happens when particles meet, exchange forces, or transform into other particles.
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Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Feynman diagrams are like particle interaction maps that make complex physics much easier to understand. Think of them as comic strips showing what happens when particles bump into each other or change into different types.
These diagrams use simple rules: time flows from left to right, and space runs vertically. Straight lines represent particles like protons and electrons, whilst wavy lines show force-carrying particles like photons.
Quick Tip: The beauty of Feynman diagrams is that they turn complicated maths into simple pictures - perfect for visualising what's really happening in the particle world!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When protons collide with protons, they don't actually touch - instead, they exchange a photon (represented by the wavy line γ). This electromagnetic interaction is what causes the particles to repel each other.
Electron-electron collisions work exactly the same way. Two electrons approach each other, exchange a photon, then fly apart due to their negative charges repelling.
The proton-antineutrino interaction is more complex because it involves the weak nuclear force. Here, a proton transforms into a neutron by emitting a W+ boson, which then interacts with an antineutrino to produce a positron (β+).
Remember: Different forces use different exchange particles - photons for electromagnetic force, W and Z bosons for weak nuclear force!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Beta decay comes in two flavours, and Feynman diagrams show exactly what's happening inside the nucleus. In β- decay, a neutron transforms into a proton by emitting a W- boson, which then decays into an electron and an antineutrino.
β+ decay (positron emission) works in reverse. A proton becomes a neutron by emitting a W+ boson, which then creates a positron and a neutrino.
The neutron-neutrino interaction demonstrates how neutrinos can occasionally interact with matter, even though they're incredibly shy particles that usually pass straight through everything.
Key Point: These diagrams show that what we call "decay" is actually particles transforming through exchange of W bosons - nature's way of changing one type into another!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Electron capture happens when a proton "swallows" an electron from the atom's inner shell. The diagram shows how the electron and proton combine via a W+ boson to produce a neutron and a neutrino.
Electron-proton collisions can result in similar outcomes, where the collision energy allows the particles to interact through the weak nuclear force rather than just electromagnetic repulsion.
These interactions are crucial for understanding how stars generate energy and how certain types of radioactive materials behave in medical applications.
Pro Tip: Notice how all these weak force interactions involve W bosons - they're like the universal translators that allow different particle types to interact and transform!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the mechanisms of particle interactions through exchange particles and Feynman diagrams. This summary covers key concepts such as beta decay, fundamental forces, and the role of bosons in particle physics, essential for exam preparation.
PhysicsExplore detailed notes covering essential A-Level Physics concepts, including stellar luminosity, electromagnetic radiation, nuclear decay, and gas laws. This resource is designed for AQA and other exam boards, featuring interactive flashcard-style navigation for effective revision. Access the full notes here: https://www.notion.so/Physics-Revision-AQA-A-Level-a87264d9f28c4302b.
PhysicsComprehensive revision notes on Thermal Physics, including key concepts such as phase changes, specific latent heat, the ideal gas law, and the first law of thermodynamics. Ideal for AQA A Level Physics students preparing for exams, with practice questions included to enhance understanding.
PhysicsExplore key concepts in nuclear physics, including alpha decay, gamma radiation, and the structure of the nucleus. This summary provides essential information on radioactive emissions, their properties, and implications for safety. Ideal for AQA A Level Physics revision.
PhysicsExplore key concepts in thermal physics, including internal energy, specific heat capacity, and the ideal gas law. This summary covers the relationships between temperature, pressure, and volume, as well as the kinetic theory of gases and latent heat. Ideal for A-Level physics students seeking a concise overview of essential topics.
PhysicsDive into the fundamentals of electric fields, including electric potential, forces, and their relationship with gravitational fields. This summary covers key concepts such as Coulomb's law, electric potential energy, and the behavior of charged particles in uniform fields. Ideal for students seeking a clear understanding of electrostatics.
PhysicsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
