2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187470Low energy proton-proton scattering is studied in pionless effective field theory. Employing the dimensional regularization and MS-bar and power divergence subtraction schemes for loop calculation, we calculate the scattering amplitude in 1S0 channel up to next-to-next-to leading order and fix low-energy constants that appear in the amplitude by effective range parameters. We study regularization scheme and scale dependence in separation of Coulomb interaction from the scattering length and effective range for the S-wave proton-proton scattering.23 pages, 6 eps figures, revised considerably, accepted for publication in Phys. Rev. CNuclear TheoryHigh Energy Physics - Phenomenologytext