Are Pi-mesons and W-bosons Identical? Exploring Particle Decay

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In summary, the conversation discusses the similarities and differences between the decay products of the pi- and W- particles, and whether they can be considered identical. The pi- is a composite particle made of quarks, while the W- is a fundamental particle. While they have the same spin, they have different masses and decay channels. The concept of structure conservation is mentioned, but it is not applicable in this case.
  • #1
talanum52
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Homework Statement
pi- =W-?
Relevant Equations
pi- = W- ?
They decay to identical particles but are they identical?
 
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What are your own efforts in trying to answer this question?
 
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  • #3
talanum52 said:
Homework Statement:: pi- =W-?
Relevant Equations:: pi- = W- ?

They decay to identical particles but are they identical?
Can you list the properties of each of these particles?

-Dan
 
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  • #4
topsquark said:
Can you list the properties of each of these particles?
They don't have the same mass and spin. Because they decay to the same particles, there must be additional particles in their decay formulas, that isn't the same, because spin is a conserved quantity.
 
  • #5
talanum52 said:
They don't have the same mass and spin. Because they decay to the same particles, there must be additional particles in their decay formulas, that isn't the same, because spin is a conserved quantity.
They do, indeed, have different masses. But why do you say they have different spins? They are both spin 1 bosons.

You are looking only at decay products. What you are not looking at is the more basic stuff. Here's a brief rundown.

A ##\pi^-## is made of a pair of bound quarks: a ##\overline{u}## and a d. It has a spin of 1 and an isospin of -1, and being made of quarks participates in the strong nuclear, weak nuclear, and electromagnetic forces.

A ##W^-## is a weak gauge boson and is a fundamental particle. It has a spin of 1 and an isospin of 0. It is not made of quarks and participates in the weak nuclear and electromagnetic forces.

(Also look up weak isospin.)

The mass difference doesn't imply that there are any particles missing from the decay lists, it just means that the decays from the ##W^-## are more energetic.

So the main difference is that the ##W^-## is a fundamental weak gauge boson and the ##\pi^-## is a composite meson.

-Dan
 
  • #6
The pions are pseudoscalar particles, the W-bosons vector ones. I've no clue, how one can get to the idea they were the same particles to begin with.
 
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vanhees71 said:
I've no clue, how one can get to the idea they were the same particles to begin with.
They decay to identical particles - that's why.
 
  • #8
talanum52 said:
They decay to identical particles - that's why.
Are decay products the same as their constituents?

Neutral pion decays into two photons, is the pion composed of photons?

Note that ##\pi^-## has several decay channels, same with the ##W^-## boson.
 
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malawi_glenn said:
Are decay products the same as their constituents?

Neutral pion decays into two photons, is the pion composed of photons?
I'm arguing that structure is conserved. Then the neutral pion's substructures cancel (not the energy).
 
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  • #10
talanum52 said:
I'm arguing that structure is conserved. Then the neutral pion's substructures cancel (not the energy).
It's an interesting idea, but it doesn't work well in practice. In fact, this example shows why you can't make this argument in general: the ##W^-## is a fundamental particle and does not have any structure to conserve. And as there are many ways in which it can decay it would be hard to say, just by looking at the daughters, what the original particle might have been before the decay. (Possible, of course, but hard.)

-Dan
 
  • #11
talanum52 said:
I'm arguing that structure is conserved. Then the neutral pion's substructures cancel (not the energy).

Define "structure"and how/why it would be conserved.

This is clearly not homework, looks more like own idea/speculation of yours.

##W^-## boson can decay into bottom quark (plus another lighter quark), ##\pi^-## can not. Case closed.
 
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malawi_glenn said:
Define "structure"and how/why it would be conserved.
Structure is the quantum numbers, mass, velocity and the space points and left out points that carries it. In my model of particles. It just seems conserved because this is the most economical.

It is work at home.
 
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  • #13
talanum52 said:
In my model of particles
This is personal theory, which is off limits here. Your legitimate question has been answered.

Thread closed.
 
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FAQ: Are Pi-mesons and W-bosons Identical? Exploring Particle Decay

Are Pi-mesons and W-bosons the same particle?

No, Pi-mesons (or pions) and W-bosons are not the same particle. Pi-mesons are mesons composed of a quark and an antiquark, while W-bosons are gauge bosons that mediate the weak force. They have different properties, masses, and roles in particle physics.

What are the main differences between Pi-mesons and W-bosons?

Pi-mesons are much lighter than W-bosons and are involved in strong interactions, while W-bosons are heavy particles that mediate the weak force. Pi-mesons are composed of quark-antiquark pairs, whereas W-bosons are elementary particles without substructure.

How do Pi-mesons decay?

Pi-mesons can decay through weak interactions into lighter particles such as muons and neutrinos. For example, a charged pion (π⁺) typically decays into a muon (μ⁺) and a muon neutrino (ν_μ).

How do W-bosons decay?

W-bosons can decay into various pairs of fermions, such as a lepton and a neutrino, or a quark and an antiquark. For example, a W⁺ boson can decay into a positron (e⁺) and an electron neutrino (ν_e) or into an up quark (u) and a down antiquark (d̅).

Why is it important to understand the differences between Pi-mesons and W-bosons?

Understanding the differences between Pi-mesons and W-bosons is crucial for comprehending the fundamental forces and interactions in particle physics. It helps in distinguishing the roles of different particles in various processes, such as particle decay and interactions, thus contributing to our overall knowledge of the universe at the most fundamental level.

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