Metastable Defects in the Generic 2HSM

A new kind of classically stable static solitons called metastable quasi-topological defects (MQTD) and a systematic method to search for them is presented, with examples from realistic particle physics models. They are characterized by a topological winding number, which is not absolutely conserved so that the MQTD may be converted to radiation by quantum mecanical tunneling. The two-Higgs standard model (2HSM) supports the existence of classically stable membranes for Higgs masses consistent with present day phenomenology and with perturbative unitarity, as well as with loop corrected MSSM. We also comment upon the possibility of metastable strings in the generic 2HSM.