We study the ^ { 1 } S _ { 0 } proton pairing gap in neutron star matter putting emphasis on influence of the Dirac effective mass and the proton fraction on the gap within the relativistic Hartree-Bogoliubov model .
The gap equation is solved using the Bonn- B potential as a particle-particle channel interaction .
It is found that the maximal pairing gap \Delta _ { \mathrm { max } } is 1–2 MeV , which has a strong correlation with the Dirac effective mass .
Hence we suggest that it serves as a guide to narrow down parameter sets of the relativistic effective field theory .
Furthermore , the more slowly protons increase with density in the core region of neutron stars , the wider the superfluid range and the slightly lower the peak of the gap become .