Primordial monopoles, proton decay, gravity waves and GUT inflation
  We consider non-supersymmetric GUT inflation models in which intermediate
mass monopoles may survive inflation because of the restricted number of
e-foldings experienced by the accompanying symmetry breaking. Thus, an
observable flux of primordial magnetic monopoles, comparable to or a few orders
below the Parker limit, may be present in the galaxy. The mass scale associated
with the intermediate symmetry breaking is $10^{13}$ GeV for an observable flux
level, with the corresponding monopoles an order of magnitude or so heavier.
Examples based on $SO(10)$ and $E_6$ yield such intermediate mass monopoles
carrying respectively two and three units of Dirac magnetic charge. For GUT
inflation driven by a gauge singlet scalar field with a Coleman-Weinberg or
Higgs potential, compatibility with the Planck measurement of the scalar
spectral index yields a Hubble constant (during horizon exit of cosmological
scales) $H \sim 7$--$9\times10^{13}$ GeV, with the tensor to scalar ratio $r$
predicted to be $\gtrsim0.02$. Proton lifetime estimates for decays mediated by
the superheavy gauge bosons are also provided.
