2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55801From the Dirac action on the world sheet, an effective action is obtained by integrating over the 4-dimensional fermion fields pulled back to the world sheet. This action consists of the Nambu-Goto area term with right dimensionful constant in front, extrinsic curvature action and the topological Euler characteristic term.9 pagesHigh Energy Physics - Theorytext