The first measurements of the polarized structure function ${\sigma }_{{\mathit{LT}}^{\text{'}}}$ for the reaction ${}^1\mathrm{H}$$(\overrightarrow{e},e^{\text{'}}{K}^{+})\Lambda$ in the nucleon resonance region are reported. Measurements are included from threshold up to $W=2.05$ GeV for central values of $Q^2$ of 0.65 and 1.00 GeV${}^2$, and nearly the entire kaon center-of-mass angular range. ${\sigma }_{{\mathit{LT}}^{\text{'}}}$ is the imaginary part of the longitudinal-transverse response and is expected to be sensitive to interferences between competing intermediate $s$-channel resonances, as well as resonant and nonresonant processes. The results for ${\sigma }_{{\mathit{LT}}^{\text{'}}}$ are comparable in magnitude to previously reported results from CLAS for ${\sigma }_{\mathit{LT}}$, the real part of the same response. An intriguing sign change in ${\sigma }_{{\mathit{LT}}^{\text{'}}}$ is observed in the high $Q^2$ data at $W\approx 1.9$ GeV. Comparisons to several existing model predictions are shown.

• Received 1 February 2008

DOI:https://doi.org/10.1103/PhysRevC.77.065208