2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/182873In Witten's open cubic bosonic string field theory and Berkovits' superstring field theory we investigate solutions of the equations of motion with appropriate source terms, which correspond to Callan-Maldacena solution in Born-Infeld theory representing fundamental strings ending on the D-branes. The solutions are given in order by order manner, and we show some full order properties in the sense of (alpha)'-expansion. In superstring case we show that the solution is 1/2 BPS in full order.21 pages, 4 figures, LaTeX, v2: minor changes v3: discussion on source terms and supersymmetric case are largely corrected, results unchanged v4: some clarification addedHigh Energy Physics - Theorytext