Trajectories and particle creation and annihilation in quantum field theory

We develop a theory based on Bohmian mechanics in which particle world lines can begin and end. Such a theory provides a realist description of creation and annihilation events and thus a further step towards a beable-based formulation of quantum eld theory, as opposed to the usual observable-based formulation which is plagued by the conceptual diculties|like the measurement problem|of quantum mechanics.