# Is the coupling constant just Gz for all these interactions?

• venomxx
In summary, the Z boson can couple to leptons and their antiparticles, as well as quarks and their corresponding antiquarks. The coupling constant for these interactions is Gz, but it may be multiplied by Sin(z) for some interactions. This is due to the presence of CPT violations in the weak interaction, which was recognized with the Nobel prize for electro/weak theory. For quarks, the coupling constant varies depending on the type of quarks involved, while for leptons it is simply Gz.
venomxx

## Homework Statement

Just a quick question, the Z can couple to leptons and there antiLeptons and quarks and there corresponding antiquark. Is the coupling constant just Gz for all these interactions? Or is it Gz.Sin(z) for some and not for others?

Iv seen different notation and am wondering why?

venomxx said:

## Homework Statement

Just a quick question, the Z can couple to leptons and there antiLeptons and quarks and there corresponding antiquark. Is the coupling constant just Gz for all these interactions? Or is it Gz.Sin(z) for some and not for others?

Iv seen different notation and am wondering why?

What is the solution of the photon?

ie

http://upload.wikimedia.org/wikipedia/commons/8/8c/Standard_deviation_diagram.svg

In SR?

ie

$$\bar{x}=x$$

and

$$\bar{z}=z$$

The coupling constant is constant. so $$G_z=Gz.Sin(z)$$ if there are no CPT violations.

Charge Parity Time (CPT)

Thus CPT symmetry.

And thus QFT:

http://en.wikipedia.org/wiki/Quantum_field_theory

Last edited by a moderator:
Cheers for the response :)

So for a Z --> e-e+ and Z--> qq" the coupling constants would be the same? Gz = gz*Sin(z)? I know that it changes for the weak depending on if its interacting with quarks or leptons, I am still unsure of why the difference?

Also out of curiosity... i thought it can't be constant because of the 'running of the coupling constants' idea?

venomxx said:
Cheers for the response :)

So for a Z --> e-e+ and Z--> qq" the coupling constants would be the same? Gz = gz*Sin(z)? I know that it changes for the weak depending on if its interacting with quarks or leptons, I am still unsure of why the difference?

Also out of curiosity... i thought it can't be constant because of the 'running of the coupling constants' idea?

Exactly weak has CPT violations inherent in it thus The Nobel prize for electro/weak theory.

Schrodinger's Dog said:
Exactly weak has CPT violations inherent in it thus The Nobel prize for electro/weak theory.

Electroweak theory has CP violations. No theory has CPT violations.

Subsequently i have found it to be a little different then mentioned above:

(z --> uu') has a coupling constant GzCos(z)
(z --> dd') has a coupling constant GzCos(z)

(z --> cc') has a coupling constant GzSin(z)
(z --> ss') has a coupling constant GzSin(z)

Can i confirm that this is correct? Also i am still unsure for leptons, am i to assume its just Gz like for W bosons?

Cheers

## 1. What is the coupling constant in physics?

The coupling constant in physics is a numerical value that describes the strength of the interaction between two particles. It is used to calculate the probability of a particular interaction occurring.

## 2. Is the coupling constant the same for all interactions?

No, the coupling constant varies depending on the type of interaction. For example, the coupling constant for the strong nuclear force is different from the coupling constant for the weak nuclear force.

## 3. How is the coupling constant related to Gz?

The coupling constant and Gz are both used to describe the strength of interactions in particle physics, but they are not the same thing. Gz is a specific coupling constant that is used in certain equations to describe interactions between particles.

## 4. How is the coupling constant determined experimentally?

The coupling constant is determined through experimental measurements and observations. Scientists use data from particle accelerators and other experiments to calculate the coupling constant for different interactions.

## 5. Can the coupling constant change over time?

The coupling constant is considered a fundamental constant in physics, meaning it is not expected to change over time. However, some theories suggest that the coupling constant may have varied in the early stages of the universe's formation.

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