Massive Bosons

[SLD]

I don’t understand how a particle like the W and Z can be so massive. They are more than an atom of iron! But they decay into nothing but insignificant particles such as a positron and a neutrino. What’s really happening here? Does a Uranium atom suddenly gain a huge amount of weight when it spontaneously decays? Even if just for a brief moment? What happens to the mass? I guess the positron and neutrino have enough energy to account for that and that’s why they go flying off at high speeds.

 

[skepticalbip]

Are you forgetting the energy release? The excess mass is released as energy as evidenced by the effects of nuclear weapons or nuclear power plants.

 

[bilby]

I don’t understand how a particle like the W and Z can be so massive. They are more than an atom of iron! But they decay into nothing but insignificant particles such as a positron and a neutrino. What’s really happening here? Does a Uranium atom suddenly gain a huge amount of weight when it spontaneously decays? Even if just for a brief moment? What happens to the mass? I guess the positron and neutrino have enough energy to account for that and that’s why they go flying off at high speeds.

Mass is just energy that's not doing anything right now.

 

[Swammerdami]

Mass is just energy that's not doing anything right now.

Yes, I know I should lose weight, but do you have to rub it in?

 

[SLD]

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

 

[bilby]

View attachment 32213

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

Energy.

 

[Bomb#20]

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

According to the rules of quantum mechanics, energy isn't actually conserved except in the long run. An interaction is in effect allowed to borrow energy from the universal bank as long as it returns the energy when it's done, with the provision that the more energy it borrows, the sooner it has to put it back. I gather it's because if you multiply energy by time you get the same units as Planck's Constant, and that makes the Uncertainty Principle apply. This is why "quantum tunneling" can happen.

 

[skepticalbip]

View attachment 32213

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

I apparently misunderstood your question in the OP (my error). You seemed to be asking several different questions. I took your "Does a Uranium atom suddenly gain a huge amount of weight when it spontaneously decays? Even if just for a brief moment? What happens to the mass?" to be asking (in a rather confused way) why the decay products of the fission of uranium have less mass than the Uranium. The answer to this would be that the total binding energy of the decay products' nucleus would be less than the binding energy of the uranium nucleus... the difference being lost as energy.

Now it looks like the question is about how to understand Feynman diagrams, not what happens to some of the nuclear binding energy that contributed to the mass of the uranium atom. The W and Z in Feynman diagrams are virtual particles, not nucleons. As far as measuring the mass of the uranium atom is concerned, they don't exist. Maybe a better question to ask would be, "where does the mass of the W and Z come from and where does it go?" since they are only virtual particles. As I understand, the answer would be that the energy/mass would be borrowed from and returned to the Higgs field.

 

[barbos]

View attachment 32213

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

W in that diagram is virtual, it does not really have mass defined.
It has energy and momentum and both of them conserves exactly.

 

[barbos]

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

According to the rules of quantum mechanics, energy isn't actually conserved except in the long run. An interaction is in effect allowed to borrow energy from the universal bank as long as it returns the energy when it's done, with the provision that the more energy it borrows, the sooner it has to put it back. I gather it's because if you multiply energy by time you get the same units as Planck's Constant, and that makes the Uncertainty Principle apply. This is why "quantum tunneling" can happen.

That's widely popular (on TV) misconception. There is no such thing as borrowing energy, it is conserved exactly everywhere. You don't need to borrow energy to create heavy virtual particle. You can just create it and give it whatever energy you have, even zero energy.

Also, quantum tunneling is no different from classical physics tunneling.

 

[barbos]

View attachment 32213

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

I apparently misunderstood your question in the OP (my error). You seemed to be asking several different questions.

No, it's actually the same question. On that diagram, practically massless neutrino "decays" into two massive particles, hence his confusion.

 

[Bomb#20]

That's widely popular (on TV) misconception. There is no such thing as borrowing energy, it is conserved exactly everywhere. You don't need to borrow energy to create heavy virtual particle. You can just create it and give it whatever energy you have, even zero energy.

Also, quantum tunneling is no different from classical physics tunneling.

Classical physics tunneling? You mean when a proton fuses with another proton in spite of not having enough kinetic energy to overcome the electrostatic potential barrier, it uses one of these?

 

[skepticalbip]

Here’s two examples of the W particle interacting. A neutrino, which is virtually massless, emits a particle which has the mass of an iron atom, then this changes a quark which is also an insignificant fraction of that mass. Where did all this come from and go to?

According to the rules of quantum mechanics, energy isn't actually conserved except in the long run. An interaction is in effect allowed to borrow energy from the universal bank as long as it returns the energy when it's done, with the provision that the more energy it borrows, the sooner it has to put it back. I gather it's because if you multiply energy by time you get the same units as Planck's Constant, and that makes the Uncertainty Principle apply. This is why "quantum tunneling" can happen.

That's widely popular (on TV) misconception. There is no such thing as borrowing energy, it is conserved exactly everywhere. You don't need to borrow energy to create heavy virtual particle. You can just create it and give it whatever energy you have, even zero energy.

Also, quantum tunneling is no different from classical physics tunneling.

There are various interpretations. My understanding of quantum tunneling is that if the wave function of a particle extends through the potential barrier then there is a probability, defined by the Schrodinger equation, of the particle being found outside the potential well even though it doesn't have sufficient energy to overcome the barrier. That is a bit different than classical physics.

 

[barbos]

That's widely popular (on TV) misconception. There is no such thing as borrowing energy, it is conserved exactly everywhere. You don't need to borrow energy to create heavy virtual particle. You can just create it and give it whatever energy you have, even zero energy.

Also, quantum tunneling is no different from classical physics tunneling.

Classical physics tunneling? You mean when a proton fuses with another proton in spite of not having enough kinetic energy to overcome the electrostatic potential barrier, it uses one of these?

Photon tunneling (through thin layer of optically less dense material) It's fully classical effect which mathematically the same as quantum tunneling.

 

[steve_bank]

To me the short answer is mass and energy are models constructed to model reality. Things are what they given how we measure and our units of measurements.

When model does not match reality, model changes. Dark matter.