Intermediate State in Standard Model Book - Clarify!

  • Thread starter neelakash
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In summary, particles can exist as part of an intermediate state for a specific amount of time, which is calculated using the formula h/(Mc^2) where h is Planck's constant divided by 2π and M is the mass of the particle. This refers to particles that are unstable and can be characterized as resonances in experimental data. This can be seen in the example of the Z boson in a Feynman diagram, where it exists for a specific amount of time before decaying into something else. This formula applies to all types of bosons, including the photon which has a mass of zero and therefore has an infinite lifetime. The underlined part is referring to the fact that particles can only exist as an intermediate state
  • #1
neelakash
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In a standard model book I find this:
a particle of mass M can exist as a part of an intermediate state for time `h/(Mc^2) where `h=h/2π


I cannot understand the underlined part.Which intermediate state are they referring to?
 
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  • #2
Spontaneously I would say that with "as a part of an intermediate state" the mean a state like, for example, the Z in the following diagram?
http://www-sldnt.slac.stanford.edu/alr/images/epem_toZ.jpg

That is, it can not be the final product, but only exist for the time [tex]\hbar/(Mc^{2})[/tex] before it need to decay into something else.
 
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  • #3
Since I do not know very much the Weak interaction...are you sure that it would be a Z boson in a Feynman diagram?Do not take me otherwise,the formula holds for any type of bosons:like photon.Since photon mass is zero,the lifetime and range of photon is infinite...So,in such cases how will you explain the intermediate state?
 
  • #4
OK buddy you are correct.The point where I was stumbling is clear now.Thank you.
 
  • #5
neelakash said:
In a standard model book I find this:
a particle of mass M can exist as a part of an intermediate state for time `h/(Mc^2) where `h=h/2π


I cannot understand the underlined part.Which intermediate state are they referring to?

Experimentally, we often caracterize particles as resonances (when the particle is unstable).
In the case of the Z quoted above you can find the resonance plot on this web page (first plot) :
http://aleph.web.cern.ch/aleph/aleph/newpub/physics.html
Below the resonance, contributions of feynman graphs like e+e- -> photon* -> qq are negligible.
 

1. What is the "Intermediate State" in the Standard Model?

The Intermediate State in the Standard Model refers to the temporary existence of a particle during a particle interaction. These particles are often referred to as "virtual particles" and do not have a long lifespan like other particles in the Standard Model.

2. How does the Intermediate State contribute to the understanding of particle interactions?

The Intermediate State plays a crucial role in understanding the fundamental forces and interactions between particles in the Standard Model. It helps to explain the exchange of energy and momentum between particles during interactions.

3. Can the Intermediate State be directly observed in experiments?

No, the Intermediate State cannot be directly observed in experiments. As virtual particles, they do not have enough time to exist and be detected by experiments. However, their effects can be observed indirectly through the behavior of other particles involved in the interaction.

4. Are there different types of Intermediate States in the Standard Model?

Yes, there are four main types of Intermediate States in the Standard Model: W and Z bosons, gluons, and photons. Each of these particles mediates a different fundamental force in the Standard Model.

5. What is the significance of the Intermediate State in the Standard Model?

The Intermediate State is crucial in the Standard Model as it helps to explain the interactions between particles and provides a framework for understanding the fundamental forces of nature. It also plays a role in the development of new theories and models in particle physics.

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