RG flows in d dimensions, the dilaton effective action, and the a-theorem
Abstract
Motivated by the recent dilaton-based proof of the 4d a-theorem, we study the dilaton effective action for RG flows in d dimensions. When d is even, the action consists of a Wess-Zumino (WZ) term, whose Weyl-variation encodes the trace-anomaly, plus all Weyl-invariants. For d odd, the action consists of Weyl-invariants only. We present explicit results for the flat-space limit of the dilaton effective action in d-dimensions up to and including 8-derivative terms. GJMS-operators from conformal geometry motivate a form of the action that unifies the Weyl-invariants and anomaly-terms into a compact general- d structure. A new feature in 8d is the presence of an 8-derivative Weyl-invariant that pollutes the O( p 8)-contribution from the WZ action to the dilaton scattering amplitudes; this may challenge a dilaton-based proof of an a-theorem in 8d. We use the example of a free massive scalar for two purposes: 1) it allows us to confirm the structure of the d-dimensional dilaton effective action explicitly; we carry out this check for d = 3, 4, 5, . . . , 10; and 2) in 8d we demonstrate how the flow Δ a = a UV - a IR can be extracted systematically from the O( p 8)-amplitudes despite the contamination from the 8-derivative Weyl-invariant. This computation gives a value for the a-anomaly of the 8d free conformal scalar that is shown to match the value obtained from zeta-function regularization of the log-term in the free energy.
- Publication:
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Journal of High Energy Physics
- Pub Date:
- March 2013
- DOI:
- 10.1007/JHEP03(2013)034
- arXiv:
- arXiv:1209.3424
- Bibcode:
- 2013JHEP...03..034E
- Keywords:
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- Field Theories in Higher Dimensions;
- Anomalies in Field and String Theories;
- Renormalization Group;
- High Energy Physics - Theory
- E-Print:
- 31 pages, 7 figures. v.2 minor corrections, references added