# Does the ensemble of effective Lagrangians in the String theory landscape mostly include gauge theories?

String theory false vacua can be described by effective Lagrangians at low energy. Is there generally a correspondence between these effective Lagrangians and SU(N) gauge theories? Or do the effective Lagrangians often not respect local invariance with respect to some or any gauge groups?

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In $d=4$, there must be pretty much always a gauge group in the spectrum. It's not a theorem but there's strong evidence for it. Note that to find a gauge group, it's enough to find any spin-one light string excitation. A Yang-Mills symmetry must exist to render its negative-norm time-like polarization harmless - in fact, one may explicitly show by stringy methods that the gauge symmetry is there in any formalism that is Lorentz-covariant. The spin-1 fields arise either from the 10D gauge group e.g. in braneworlds or heterotic strings or from the RR fields or B-fields wrapped on cycles. –  Luboš Motl Mar 26 '13 at 8:59
@Luboš Motl -- Great, thanks! Do you know of any references (or key words to search for) that I could look up? –  user1247 Mar 26 '13 at 9:03