We use the relativistic distorted-wave impulse approximation (RDWIA) to study the effects of negative-energy components of Dirac wave functions on the left-right asymmetry for $(e,e^{\text{'}}p)$ reactions on ${}^{16}\mathrm{O}$ with $0.2\le Q^2\le 0.8$ and ${}^{12}\mathrm{C}$ with $0.6\le Q^2\le 1.8(\text{GeV}/c){}^2$. Spinor distortion is more important for the bound state than for the ejectile and the net effect decreases with $Q^2$. Spinor distortion breaks Gordon equivalence and the data favor the CC2 operator with intermediate coupling to the sea. The left-right asymmetry for $Q^2\lesssim 1.2(\text{GeV}/c){}^2$ is described well by RDWIA calculations, but at $Q^2=1.8(\text{GeV}/c){}^2$ the observed variation with missing momentum is flatter than predicted.

• Received 1 February 2005

DOI:https://doi.org/10.1103/PhysRevC.72.014602