RELATIVISTIC Y-SCALING AND THE COULOMB SUM-RULE IN NUCLEI

In this paper dividing factors G(L) and G(T) are constructed for the l ongitudinal and transverse responses of the relativistic Fermi gas in such a way that the reduced responses so obtained scale, These factors parallel another dividing factor studied previously, H-L, that yields a (different) reduced response which fulfills the Coulomb sum rule. G (L), G(T) and H-L are all found to be only very weakly model-dependent , thus providing essentially universal dividing factors. To explore th e residual degree of dependence which remains, the scaling and sum rul e properties of several specific models have been considered. It is se en that the relativistic Fermi gas (by construction) and also typical shell-model reduced responses successfully scale and satisfy the Coulo mb sum rule, as do experimental results at medium to high momentum tra nsfers. On the other hand, it is observed that the quantum hadrodynami c model does so only if interaction effects become weaker with increas ing momentum transfer, as predicted in the most recent versions of tha t model. (C) 1998 Elsevier Science B.V.