# How Does a New Lagrangian Term Affect the Fine Structure Constant?

• LCSphysicist
In summary, the conversation discusses the addition of a term to the Lagrangian of the Standard Model and its effect on the fine structure constant. It also raises questions about the role of phi as a field and the significance of constants Fphi and Aphi. The discussion also mentions the potential non-renormalizability of the term.
LCSphysicist
Homework Statement
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Relevant Equations
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If we add to the Lagrangian of SM a term $$\frac{{\phi}F_{\mu v}F^{\mu v}}{F_{\phi}}$$

How does the fine structure constant ##\alpha## changes as $$\phi = A_\phi cos(m_{\phi} t)$$?

I am having some hard time to finding out where i should start. I remember see the strucutre constant arrising when we evaluate vertices on feynman diagrams for QED interactions... But i am too ignorant to know how to proceed..

What is Fphi and Aphi?

Is phi a field?

malawi_glenn said:
What is Fphi and Aphi?

Is phi a field?
"What is Fphi and Aphi?" I assume they are just constants... But the question says nothing about it.
Yes, phi is a field.

LCSphysicist said:
"What is Fphi and Aphi?" I assume they are just constants... But the question says nothing about it.
Yes, phi is a field.
Where did you find the problem? This is a non renormalizeable term

## 1. What is the fine structure constant?

The fine structure constant, denoted by the symbol α (alpha), is a dimensionless physical constant that describes the strength of the electromagnetic interaction between elementary particles.

## 2. What is the value of the fine structure constant?

The currently accepted value of the fine structure constant is approximately 1/137, or 0.0072973525664. This value is a fundamental constant of nature and does not depend on any specific unit system.

## 3. How is the fine structure constant related to other physical constants?

The fine structure constant is related to other important physical constants, such as the speed of light, Planck's constant, and the elementary charge. It is also related to the strength of the strong and weak nuclear forces.

## 4. What is the significance of the fine structure constant?

The fine structure constant plays a crucial role in determining the properties of atoms and molecules, as well as the behavior of particles at the quantum level. It is also used in various theoretical models and calculations in physics.

## 5. Has the value of the fine structure constant changed over time?

Although there have been attempts to measure and verify changes in the fine structure constant, there is currently no evidence to suggest that its value has changed over time. It is considered to be a fundamental constant of nature that remains constant throughout the universe.

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