How do neutrinos conserve angular momentum?

In summary, beta decay occurs when a neutron decays into a proton and an electron. However, this violates the conservation of angular momentum since all particles involved have a spin of 1/2. To solve this, a neutrino with spin 1/2 is proposed to also exist in the process, resulting in the equation neutron → proton + electron + neutrino. This still follows the conservation of angular momentum as the overall spin remains 1/2.
  • #1
SteveDC
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I'm learning about beta decay and as I understand in beta decay we get:

neutron → proton + electron

And since all these have spin 1/2 we have that the conservation of angular momentum is not conserved.

The neutrino with spin 1/2 is proposed to also exist in the process to solve this so that:

neutron → proton + electron + neutrino

But I don't understand how this conserves angular momentum since haven't you now gone from a spin 1/2 particle one side to three spin 1/2 particles the other side so the spin has changed by 1. Shouldn't the change in spin need to be zero to conserve angular momentum?
 
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  • #2
SteveDC said:
But I don't understand how this conserves angular momentum since haven't you now gone from a spin 1/2 particle one side to three spin 1/2 particles the other side so the spin has changed by 1. Shouldn't the change in spin need to be zero to conserve angular momentum?

The angular momentum has not changed. You can couple three spin 1/2 to an overall spin 1/2 (simply couple two of the spins anti-parallel).
 
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Related to How do neutrinos conserve angular momentum?

1. What is angular momentum?

Angular momentum is a physical quantity that measures the amount of rotational motion of an object. It is defined as the product of an object's moment of inertia and its angular velocity.

2. How do neutrinos conserve angular momentum?

Neutrinos, like all particles, have a property called spin which contributes to their overall angular momentum. When neutrinos interact with other particles, their spin must be conserved, meaning the total angular momentum of the system before and after the interaction remains the same.

3. Why is it important for neutrinos to conserve angular momentum?

Conservation of angular momentum is a fundamental principle in physics that helps us understand the behavior of particles and their interactions. It also allows us to make predictions about the outcomes of particle interactions.

4. How is the conservation of angular momentum demonstrated in neutrino experiments?

In neutrino experiments, scientists measure the momenta and spins of particles before and after a neutrino interaction. By comparing these values, they can determine whether angular momentum was conserved in the interaction.

5. Can neutrinos break the law of conservation of angular momentum?

No, neutrinos cannot break the law of conservation of angular momentum. This law is a fundamental principle of physics that has been tested and confirmed through numerous experiments. Neutrinos, like all particles, must follow this law in all interactions.

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