A Pati-Salam model from branes

We explore the possibility of embedding the Pati-Salam model in the context of Type I brane models. We study a generic model with U(4)(C) x U(2)(L) x U(2)(R) gauge symmetry and matter fields compatible with a Type T brane con figuration. Examining the anomaly cancellation conditions of the surplus ab elian symmetries we find an alternative hypercharge embedding that is compa tible with a low string/brane scale of the order of 5-7 TeV, when the U(4)( C) and U(2)(R) brane stack couplings are equal. Proton stability is assured as baryon number is associated to a global symmetry remnant of the broken abelian factors. It is also shown that this scenario can accommodate an ext ra low energy abelian symmetry that can be associated to lepton number. The issue of fermion and especially neutrino masses is also discussed. (C) 200 1 Published by Elsevier Science B.V.