On Coulomb threshold states

This work approaches the description of Coulomb Threshold States in terms of Nuclear Reactions Theory. The physical basis of this approach is the spatial extension, outside the nucleus radius, of the Coulomb Threshold States. The spatial extension factor is discussed according to different physical interpretations. The generalization of the one-channel spatial factor to multichannel reaction systems is obtained. The problem of the spreading of the threshold state in continuum of statistical levels is approached too. The implication of Coulomb Threshold States in the problem of optical potential threshold anomaly is also discussed. (authors)