# What is Weak interactions: Definition and 15 Discussions

In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms. The weak interaction participates in nuclear fission, and the theory describing its behaviour and effects is sometimes called quantum flavourdynamics (QFD). However, the term QFD is rarely used, because the weak force is better understood by electroweak theory (EWT).The effective range of the weak force is limited to subatomic distances, and is less than the diameter of a proton. It is one of the four known force-related fundamental interactions of nature, alongside the strong interaction, electromagnetism, and gravitation.

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1. ### A Madame Wu Experiment: Doubts & Reasoning

Hi all, I have some doubts regarding the experiment of Madame Wu. I know a strong magnetic field is used to polarise the ##^{60}Co## nuclei, then we have an anthracene scintillator on the top of the sample which will detect the electron produced in the decay: ##^{60}Co \rightarrow...
2. ### I Find Lambda Baryon Decays Cross Section Ratio

I've been asked to find the ratio between the cross sections of the two folowing decais: Using the CKM matrix and the feynman diagrams for both decays, I reach the conclusion that the Ratio is exactly 1. However, consulting this document...
3. ### Upsilon Meson Decays and B Meson Decays: Feynman Diagrams and Distance Traveled

Homework Statement (a)Draw feynman diagrams of upsilon meson. Why is decay to ##q\bar q## states suppressed? Explain why width for 4s is much wider. (b) How do B mesons decay? Why is no other type of interaction possible? Draw feynman diagrams. (c) Find the distance traveled by 1s and 4s. (d)...
4. ### Evidence that the neutrinos are different?

We know that there are 3 generations of neutrinos, namely the electron neutrino, muon neutrino and the tau neutrino. The masses are all very small compared to their respective leptons. What evidence is there that these neutrinos of different generations are distinct?
5. ### Why don't a charm-anticharm meson decay to pair of leptons?

If you consider the ##\chi_0 ## with a mass of ## 3.4 GeV/c^2## meson, why doesn't it decay to a pair of charged leptons? Technically it is possible though the weak interaction (Z boson) or EM interaction, right? Is it because it is so heavily suppressed because the strong interactions are...
6. ### Compare & contrast properties of strong & weak interactions

Hi all - in the question below I could do with some help on the "..explanation for the relative strengths..." bit, as I can't think of anything to say. 1. Homework Statement Compare and contrast the properties of the strong and weak interactions. Include in your account an explanation for the...
7. ### Weak Interactions violate Lorentz?

I was wondering. For fermions someone can find that the Lorentz group is isomorphic to SU_L(2) \times SU_R(2) . However in the Standard Model there is only left-handed neutrinos interacting with the rest of matter. If Lorentz was not partially violated, wouldn't someone expect for the left and...
8. ### Strong and weak interactions particles

Does anybody could help me to state if the following particles experience strong interactions, weak interactions, both interactions or neither of the two interactions? This is what I think: electron = strong interactions and weak interactions boson = weak interactions down quark = strong...
9. ### Weak interactions: I know why they're weak, but why are they slow?

Compared to, for example, electromagnetic interactions. Are the "weakness" and "slowness" perhaps somehow related? Perhaps both "weakness" and "slowness" can both be reformulated as "having a low probability of occurring", making the "slowness" apparent, and making the "weakness" a...
10. ### Weak interactions that change lepton flavor

Are there any W^\pm or Z^0 interactions that change lepton flavor? For example, turn an electron into a muon or vice versa? Thanks!
11. ### Strong and weak interactions in nuclear physics

Homework Statement How do we determine whether we have a strong or a weak interaction? (for the following processes) For example we have a reaction K^{-}+p\Rightarrow \Xi^{-}+K^{+} or another example K^{+}\Rightarrow \pi^{+}+\pi^{0} thanks!
12. ### Running coupling of the weak interactions

Can someone point me to a reference that explains how the (effective) running coupling behaves in the weak interactions(at 1-loop order). I couldn't find it... If I understand correctly, than the coupling is g = \frac{e}{sin(\theta_W)} where e is the QED coupling, which increases with energy...
13. ### Electroweak Interaction: Theory & Symmetry

I understand that the Colour Force is described by Quantum Chromodynamics, Electromagnetism is described by Quantum Electrodynamics and Gravity will hopefully be described by a Quantum Gravity Theory but currently General Relativity. But what Theory describes the Electroweak Interaction? Is...
14. ### Strong versus weak interactions

For the process where two neutral pions turn into two charged pions, I noticed that this can occur through both the strong and weak interactions. Through the strong interaction it is a 4-pion vertex, and through the weak interaction it involves a virtual W-particle. If I were asked on a quiz...
15. ### Which involves weak interactions?

The production of a muon/antimuon pair from an electron and positron or... The production of a neutrino/antineutrino pair from an electron and a positron? The only weak interactions I know of are beta-minus decay, beta-plus decay and electron capture. All the sources I've found say they...