Non-gaussianity at tree and one-loop levels from vector field
  perturbations
  We study the spectrum P_\zeta and bispectrum B_\zeta of the primordial
curvature perturbation \zeta when the latter is generated by scalar and vector
field perturbations. The tree-level and one-loop contributions from vector
field perturbations are worked out considering the possibility that the
one-loop contributions may be dominant over the tree level terms (both (either)
in P_\zeta and (or) in B_\zeta) and viceversa. The level of non-gaussianity in
the bispectrum, f_{NL}, is calculated and related to the level of statistical
anisotropy in the power spectrum, g_\zeta. For very small amounts of
statistical anisotropy in the power spectrum, the level of non-gaussianity may
be very high, in some cases exceeding the current observational limit.
