- #1
Paul Dirac
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The arrow for the electron antineutrino is pointing down which is against time, why is that?
Why is the anti-neutrino going against time?
In summary, the arrow pointing downwards for the electron antineutrino is simply a convention in Feynman diagrams and has no deeper meaning. It is a logical consequence of the math used in quantum field theory and should not be interpreted as an anti-particle moving backwards in time. Understanding the underlying theory and math is crucial before questioning the significance of these conventions.
The arrow for the electron antineutrino is pointing down which is against time, why is that?
- #2
Nugatory
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The math gives us the right answers in some problems (and this is one of them) if we treat an anti-particle as a regular particle moving backwards in time. That doesn't mean that an anti-particle is "really" a regular particle moving back in time.
Be aware that Feynman diagrams such as this one are easily misunderstood - they are not picctures of what the particles are really doing, they're a way of organizing the calculations to find the probability of various interactions.
Be aware that Feynman diagrams such as this one are easily misunderstood - they are not picctures of what the particles are really doing, they're a way of organizing the calculations to find the probability of various interactions.
- #3
Bill_K
Science Advisor
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Purely a convention.Paul Dirac said:
- #4
Paul Dirac
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so why does the math permit the arrow pointing downwards? which equation implies that? so do all anti-particles by convention point downwards? Thanks!
- #5
bhobba
Mentor
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Paul Dirac said:
Its simply a logical consequence of the math. Logical consequences may have a deeper meaning, or not. Experience in this case has shown its helps sometimes, but can lead to issues if pushed too far. For example one can view an electron as a positron going backwards in time. So which is it? Is it the electron going backwards in time or is it the positron? The theory is silent about that.
Before asking questions like that you need to understand the underlying theory, including the math. And the math of QFT is no walk in the park by a long shot.
Thanks
Bill
- #6
Vanadium 50
Staff Emeritus
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Nothing is going backwards in time. The arrows are a convention for writing down the mathematics. Nothing more, nothing less.
1. Why is the anti-neutrino considered to go against time?
The anti-neutrino is considered to go against time because it has the ability to change its flavor (electron, muon, or tau) as it travels through space, which is not possible for other particles. This phenomenon is known as neutrino oscillation, and it suggests that the anti-neutrino has a non-zero mass, contrary to what was previously believed.
2. How does the concept of anti-neutrino going against time relate to the theory of relativity?
The concept of anti-neutrino going against time is closely related to the theory of relativity, specifically the theory of time dilation. According to this theory, as an object approaches the speed of light, time slows down for that object. Since the anti-neutrino travels at almost the speed of light, its time is dilated, allowing it to change its flavor as it travels.
3. What implications does the anti-neutrino going against time have on particle physics?
The anti-neutrino going against time has significant implications on particle physics. It challenges our understanding of the Standard Model of particle physics and suggests the existence of new physics beyond the Standard Model. It also has implications for understanding the origins of matter and antimatter in the universe.
4. How do scientists study the anti-neutrino going against time?
Scientists study the anti-neutrino going against time through various experiments, such as the MINOS and T2K experiments. These experiments utilize powerful detectors to observe the behavior of anti-neutrinos as they travel through space. By studying the anti-neutrino oscillation, scientists can gain a better understanding of its properties and behavior.
5. What practical applications could come from understanding the anti-neutrino going against time?
Understanding the anti-neutrino going against time could have several practical applications. For example, it could help us develop new technologies for more accurate timekeeping or navigation systems. It could also lead to advancements in energy production and medical imaging. Additionally, studying the anti-neutrino could help us better understand the universe and its origins.
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