It is addressed the problem of understanding orbifold field theories in extra dimensions as limits of regular spaces. In this context, the Dirac equation of chiral fermions on a regularized version of the two-dimensional T²/Z₂ orbifold is studied.
This analysis shows how localized and bulk fermions arise in the orbifold as the resolved space approaches the orbifold limit. It also shows that not all possible fermion configurations on T²/Z₂ admit such a simple resolution, due to severe constraints on the allowed chiralities and U(1) charges of the massless four dimensional fermions (localized or not) that can be present in the orbifold. The limit in which T²/Z₂ (and its corresponding resolved space) collapses to S¹/Z₂ is also studied in detail.

SISSA, Italie