On the one-loop Fayet-Iliopoulos term in chiral four-dimensional type I orbifolds

We consider the generation of Fayet-Iliopoulos terms at one string loop in some recently found N = 1 open string orbifolds with anomalous U(1) factors with non-vanishing trace of the charge. Low-energy field theory arguments lead one to expect a one-loop quadratically divergent Fayet-Iliopoulos term. We show that a one-loop Fayet-Iliopoulos term is not generated, due to a cancellation between contributions of world-sheets of different topology. The vanishing of the one-loop Fayet-Iliopoulos term in open string compactifications is related to the cancellation of twisted Ramond-Ramond tadpoles. (C) 1999 Elsevier Science B.V.