2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179404We consider, in 5 dimensions, the low energy effective action induced by heterotic string theory including the leading stringy correction of order alpha'. In the presence of a single positive tension flat brane, and an infinite extra dimension, we present a particular class of solutions with finite 4-dimensional Planck scale and no naked singularity. A ``self-tuning'' mechanism for relaxing the cosmological constant on the brane, without a drastic fine tuning of parameters, is discussed in this context. Our solutions are distinct from the standard self-tuning solutions discussed in the context of vanishing quantum corrections in alpha', and become singular in this limit.9 pages, 1 figure, discussion of self-tuning changedHigh Energy Physics - TheoryHigh Energy Physics - Phenomenologytext