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cmcraes
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Hi all, how much merit does this answer have on Quora? There also an identical answer on Physics Stack Exchange so it'd be nice to confirm or deny the validity of these.
Thanks!
Thanks!
Orodruin said:None. Weak interactions are based on a non-Abelian gauge symmetry and furthermore the up/down charges are not interaction eigenstates (ie, there are interactions that change these charges). You cannot talk about a classical force when it comes to weak interactions and for strong interactions you can do so only for the residual strong nuclear force responsible for keeping colourless nucleons together by exchange of virtual pions.
Then how can you authoritatively say that it does not sound right?ohwilleke said:This doesn't sound right to me. Although I'm not certain of the answer and not very confident of the one posted in Physics.SE.
First of all, the question was about weak interactions. That is not just Z exchange but also includes W exchange. You cannot change the question to try to squeeze in your answer. Even if that were the case, the answer would be wrong. The Z has different couplings to L/R due to its admixture of hypercharge.ohwilleke said:Thinking about W boson interactions isn't a very clean thought experiment since W bosons have electromagnetic couplings as well as weak interaction couplings. The clean analogy to photon exchanges in electromagnetism that we know and love and understand is with Z boson exchanges.
These caveats are essentially what I consider missing from the quoted posts. It is mentioned that what is discussed is weak isospin interactions, bit it is glossed over how those relate to what many students would call ”weak interactions”, ie, W and Z exchange. Weak isospin only affects left-handed fermions and as long as you do not break electroweak symmetry those are massless and do not couple to their right-handed counterparts.Vanadium 50 said:In this case, one can only talk about the electroweak force, because what remains when you subtract off the electric force depends on the details of just how you modeled the force as long range. With that caveat:
Vanadium 50 said:Since we're only concerned about attraction and repulsion
That's an astonishing statement. Wasn't Newton the guy who played, together with his buddy Hooke with springs and all the like to explain the nature of forces? I don't see that the force excerted by a spring is especially long range. Maybe a more modern and relevant example are Yukawa forces. I also don't see why you can't consider them already in classical Newtonian mechanics and many models of the nucleus do so.Vanadium 50 said:First, since the weak interaction is short range, discussing it in terms of the Newtonian concept of "force" is doomed to failure.
In this case, those forces are very very long range in comparison. "Short range" in terms of weak interactions are of the order of ##10^{-18}## meters (essentially the inverse of the W boson mass). At that scale it is rather irrelevant to talk about "forces" in the typical sense of having a classical path that a particle follows being affected by forces that determine its acceleration. In the case of models of the nucleus, you have a potential which is related to the concept of forces but not exactly the same. You have the potential in quantum mechanical descriptions as well without having to refer to forces.DrDu said:I don't see that the force excerted by a spring is especially long range.
Are you sure that the neutrino-antineutrino bound state would be possible? As far as I understand, the existence of a bound state is not guaranteed for a Yukawa potential (there is a critical value of the screening parameter, i.e., the mass of the mediator in this case). A quick search revealed this:DrDu said:In principle, even a bound state of a neutrino and an anti-neutrino is possible, although the binding energy would be fantastically small.
The weak force is one of the four fundamental forces of nature, along with gravity, electromagnetism, and the strong nuclear force. It is responsible for radioactive decay and plays a crucial role in the stability of atomic nuclei.
The weak force acts as an attractive force by mediating interactions between subatomic particles, such as quarks and leptons. These interactions result in the exchange of particles called W and Z bosons, which causes particles to be pulled towards each other.
The weak force is responsible for processes such as beta decay, where a neutron is transformed into a proton, and electron, and an antineutrino. It also plays a role in the fusion of hydrogen atoms in the Sun, and in the production of elements heavier than iron in supernova explosions.
Unlike the other three forces, the weak force is short-ranged and only acts over very small distances. It is also the only force that can change one type of particle into another, such as transforming a neutron into a proton.
The weak force is crucial in understanding the behavior and interactions of subatomic particles. It also helps us understand the origins of the universe, as it played a significant role in the early stages of the universe's evolution and the formation of matter as we know it.