We calculate the electromagnetic form factors of a bound proton. The chiral quark-soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant modifications of the form factors in the nuclear environment. The sea quarks are almost completely unaffected, and serve to mitigate the valence quark effect. In particular, the ratio of the isoscalar electric to the isovector magnetic form factor decreases by 20% at $Q^2=1\mathrm{Ge}{\mathrm{V}}^2$ at nuclear density, and we do not see a strong enhancement of the magnetic moment.

• Received 10 September 2004

DOI:https://doi.org/10.1103/PhysRevC.70.065205