What is the weak isospin of hadrons?

In summary, the weak isospin values of various hadrons, including the proton, neutron, mesons, hyperons and other hadrons, are not available as they are only provided for fundamental fermions. The weak isospin can be calculated using Q=T3+YW/2, but the weak hypercharge values for hadrons are also not available. It is possible that the weak isospin of all hadrons is 0, as the weak interaction does not operate on the hadron as a whole, but only on its constituent quarks. However, since weak isospin is not a conserved quantum number, the question has no definitive answer.
  • #1
Ron Paul
2
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What are the weak isospins (T3 values) of various hadrons, including the proton, neutron, mesons, hyperons and other hadrons? How is the weak isospin calculated for any hadron?

Published sources provide T3 only for fundamental fermions, that is, quarks and leptons. In the fundamental bosonic sector, the photon's T3 is (0, 1), the gluon's is 0, the Higgs boson's is -1/2, the Z boson's is 0 and the charged weak bosons' is ±1. No such information appears for composite particles.

One could calculate this using Q=T3+YW/2. However, the weak hypercharge (YW) values for hadrons are also not available.

Supposedly, it is possible that the weak isospin of all hadrons is 0, since the weak interaction does not operate on the hadron as such, only on its constituent quarks. Is this the case?

Thanks in advance.
 
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  • #2
Weak isospin is not a conserved quantum number so the question has no answer.
 
  • #3
Vanadium 50 said:
Weak isospin is not a conserved quantum number so the question has no answer.
Thank you.

I interpret your answer as follows: weak isospin is a quantum number that can exist only for fundamental particles. This, because composite particles (hadrons) are the result of an interaction which does not conserve weak isospin.

Hence, my assumption that "the weak interaction does not operate on the hadron as such, only on its constituent quarks" is correct.

You say that "the question has no answer"; however, is it not possible to simply say that the weak isospin of every hadron is 0?
 
  • #4
Ron Paul said:
I interpret your answer as follows:

I said precisely none of that. Weak isospin is not a conserved quantum number so the question has no answer.
 

FAQ: What is the weak isospin of hadrons?

1. What is the definition of the weak isospin of hadrons?

The weak isospin of hadrons refers to a fundamental quantum property that describes the behavior and interactions of subatomic particles called hadrons, such as protons and neutrons. It is a quantum number that is conserved in the strong and electromagnetic interactions, but not in the weak interaction.

2. How is the weak isospin of hadrons related to the weak nuclear force?

The weak isospin of hadrons is closely related to the weak nuclear force, which is responsible for radioactive decay and plays a crucial role in the fusion reactions that power the sun. This is because the weak nuclear force only interacts with particles that have a non-zero weak isospin.

3. Are there different types of weak isospin for different types of hadrons?

Yes, there are two types of weak isospin: up-type and down-type. Up-type hadrons, such as protons, have a weak isospin of +1/2, while down-type hadrons, such as neutrons, have a weak isospin of -1/2. This difference in weak isospin is what allows for the creation of different types of hadrons through the strong nuclear force.

4. How is the weak isospin of hadrons measured and calculated?

The weak isospin of hadrons is measured and calculated through experiments that involve the interactions of subatomic particles. These experiments use mathematical models, such as the Standard Model of particle physics, to predict the weak isospin of various hadrons based on their properties and behavior.

5. How does the weak isospin of hadrons affect the stability of atoms?

The weak isospin of hadrons plays a crucial role in determining the stability of atoms. This is because the weak nuclear force is responsible for radioactive decay, which can change the number of protons and neutrons in an atom and ultimately lead to its stability or instability. Without the weak isospin, atoms would not be able to undergo radioactive decay and would remain unstable.

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