Callan-Symanzik equation in dimensionally regularized scheme

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In summary, the CS equation for the bare theory is often expressed in terms of variations with respect to a hard momentum cut-off, but can also be modeled using the epsilon of dimensional regularization (where epsilon = 4-d). Many particle physicists use dimensional regularization in their work, but most textbook explanations of the CS equation assume a hard cut-off. A helpful reference for understanding the CS equation in both regularization schemes is David J. Toms' paper "The Effective Action and the Renormalization Group" (Phys. Rev. D 21, 2805). Toms discusses the differences between the two schemes and their relationship to the CS equation.
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metroplex021
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In every textbook treatment of the CS equation for the bare theory I've seen, the CS equation (and hence the beta-function) is expressed (partly) in terms of variations with respect to the cut-off Lambda, where it is clear that this Lambda refers to a hard momentum cut-off. Can anybody direct me to an expression for the CS equation (for the bare theory) in which the cut-off is modeled by the epsilon of dimensional regularization, where epsilon =4-d, where d is the number of space dimensions? (It seems weird that (as I'm told) particle physicists almost always use dimensional regularization in their day-to-day work, and yet the textbook expos of the CS equation all seems to assume hard cut-off regularization.) Any help or hook-ups gratefully received!
 
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The best reference I can give is a paper by David J. Toms, "The Effective Action and the Renormalization Group" (Phys. Rev. D 21, 2805). In this paper, he considers the CS equation in both hard cutoff and dimensional regularization schemes. He also discusses the relationship between the two regularization schemes and how the CS equation differs in each case. Hope this helps!
 

1. What is the Callan-Symanzik equation in dimensionally regularized scheme?

The Callan-Symanzik equation in dimensionally regularized scheme is a fundamental equation in quantum field theory that describes how the coupling constants of a theory evolve with energy scale. It is used to study the behavior of renormalizable quantum field theories, such as the Standard Model of particle physics.

2. Why is dimensionally regularized scheme used in the Callan-Symanzik equation?

Dimensional regularization is a method used in quantum field theory to regulate divergent integrals that arise in perturbative calculations. It allows for the calculation of physical quantities in a way that is independent of the regularization scheme, making it a powerful tool in studying renormalizable theories.

3. How does the Callan-Symanzik equation relate to the renormalization group?

The Callan-Symanzik equation is a manifestation of the renormalization group in quantum field theory. It describes how the coupling constants of a theory change with energy scale, which is a key concept in the renormalization group. This equation allows for the study of the behavior of a theory at different energy scales and can reveal important information about its underlying structure.

4. Is the Callan-Symanzik equation applicable to all quantum field theories?

The Callan-Symanzik equation is applicable to all renormalizable quantum field theories, which includes the Standard Model of particle physics. However, it is not applicable to non-renormalizable theories, such as gravity, as these theories require different methods of regularization.

5. What are the implications of the Callan-Symanzik equation for physical predictions?

The Callan-Symanzik equation allows for the calculation of physical quantities at different energy scales, which can lead to important predictions about the behavior of a theory. It also provides a way to compare experimental results with theoretical predictions, which can help to test the validity of a theory and potentially discover new physics beyond the Standard Model.

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