  The polarized longitudinal-transverse structure function $\sigma_{LT^\prime}$
has been measured in the $\Delta(1232)$ resonance region at $Q^2=0.40$ and 0.65
GeV$^2$. Data for the $p(\vec e,e'p)\pi^o$ reaction were taken at Jefferson Lab
with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally
polarized electrons at an energy of 1.515 GeV. For the first time a complete
angular distribution was measured, permitting the separation of different
non-resonant amplitudes using a partial wave analysis. Comparison with previous
beam asymmetry measurements at MAMI indicate a deviation from the predicted
$Q^2$ dependence of $\sigma_{LT^{\prime}}$ using recent phenomenological
models.
