Short-range nuclear effects on axion emissivities by nucleon-nucleon
  bremsstrahlung
  The rates of axion emission by nucleon-nucleon (NN) bremsstrahlung are
reconsidered by taking into account the NN short range correlations. The
analytical formulas for the neutron-neutron (nn), proton-proton (pp) and
neutron-proton (np) processes with the inclusion of the full momentum
dependence of an one- and two- pion exchange nuclear potentials, in the
non-degenerate limit, are explicitly given. We find that the two-pion exchange
(short range) effects can give a significant contribution to the emission
rates, and are temperature dependent. Other short range nuclear effects like
effective nucleon mass, polarization effects and use of correlated wave
functions, are discused as well. The trend of all these nuclear effects is to
diminish the corresponding axion emission rates. Further, we estimate that the
values of the emission rates calculated with the inclusion of all these effects
can differ from the corresponding ones derived with constant nuclear matrix
elements by a factor of $\sim 24$. This leads to an uncertainty factor of $\sim
4.9$ when extracting bounds of the axion parameters
