QUARK SUBSTRUCTURE APPROACH TO HE-4 CHARGE-DISTRIBUTION

We present a study of the He-4 charge distribution based on realistic nucleonic wave functions and incorporation of quark substructure. Any central depression of the proton point density seen in modern four-bod y calculations is too small by itself to lead to a correct description of the charge distribution of 4He if folded with a fixed proton size parameter, as is usually done. We utilize six-quark structures calcula ted in the chromodielectric model for N-N interactions to find a ''swe lling'' of the proton size as the internucleon distance decreases. Thi s swelling is a result of the shea-range dynamics in the N-N system. U sing the independent pair approximation, the corresponding charge dist ribution of the proton is folded with the two-nucleon distribution gen erated from Green's function Monte Carlo calculations of the 4He nucle onic wave function. We obtain a reasonably good fit to the experimenta l charge distribution of He-4. Meson-exchange currents have not been i ncluded.