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Ultraviolet behavior of four-dimensional. sigma. models coupled to gravity

Journal Article · · Physical Review, D (Particles Fields); (USA)
; ; ;  [1]
  1. University of Athens, Panepistimiopolis, Athens 157-71 (Greece). Department of Physics, Nuclear and Particle Physics Section

In a nonlinear {sigma} model coupled to gravity we compute all one-loop divergences including contributions from both virtual gravitons and scalars {phi}{sup {ital i}} which are valued on an internal manifold {ital M}. The calculation is performed in arbitrary curved backgrounds and it is useful not only for studying the renormalization properties of this particular gravity theory but also for constructing the effective {sigma}-model Lagrangian incorporating the dominant one-loop effects near the Planck scale. The latter may be of relevance to low-energy effective theories inspired by some string models. We find that the geometry of the manifold {ital M} plays no important role in improving the ultraviolet behavior of the model. As regards the {sigma}-model effective-Lagrangian calculation we have found that a large portion of the dominant radiative effects can be absorbed by a redefinition of the four-dimensional metric {ital g}{sub {mu}{nu}}, the rest inducing renormalizations of the manifold metric {ital scrG}{sub {ital i}{ital j}} and the potential {ital V} not depending on the four-dimensional geometry. Up to terms logarithmic in the momentum cutoff scale {Lambda} having the structure ({partial derivative}{sub {Gamma}}{phi}){sup 4}, ({ital scrD}{sub {mu}}{ital scrD{nu}}{phi}){sup 2} the resulting one-loop effective theory is of the same form as the tree-level Lagrangian with the renormalized metric {ital scrG}{sub {ital i}{ital j}} and potential {ital V}.

OSTI ID:
6687306
Journal Information:
Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 42:2; ISSN PRVDA; ISSN 0556-2821
Country of Publication:
United States
Language:
English