The Axion-Nucleon Coupling and Cooling Bounds from Neutron Stars, Read Against the Limit Density

The coupling runs from 4.69e-10 at a decay constant of 10^9 GeV down to 4.69e-13 at 10^12 GeV. The adopted bound of 1.00e-09 corresponds to a minimum decay constant of 4.69e+08 GeV. The ratio of a neutron star's central density to the bound density is 1.03e-40: the star operates forty orders of magnitude below the density at which torsion would reorganise its structure, on the bound density of 9.72e+54 g per cubic centimetre. Cooling bounds therefore pass into the bounced framework completely unchanged. This study is computed from stated assumptions and published comparison values; it is not a measurement.