Nuclear Structure Functions and the Size of Diquarks in Nucleons

It is suggested that the observed difference between deep-inelastic structure functions from iron and deuterium targets comes about because two of the quarks in a nucleon are tightly bound in a diquark. It suffices for reproducing the data to assume that the diquark radius is enhanced by 10%-45% in a dense nucleus because of the disturbance from the surrounding nucleons. It is suggested how such a change of the diquark scale could be distinguished from the recently proposed change in the scale of the whole nucleon.