We have measured the ratio of yields for a single porton transferred into versus out of a projectile in reactions involving four different heavy projectiles on each of five heavy targets. There is a strong preference to transfer the proton out of the projectile, which can be understood in terms of the potential energy of the two nuclei near contact.

• Received 29 January 1968

DOI:https://doi.org/10.1103/PhysRevLett.20.802