%0 Journal Article %T Measurement of the Polarized Structure Function $¦Ò_{LT^\prime}$ for Pion Electroproduction in the Roper Resonance Region %A CLAS Collaboration %A K. Joo %A L. C. Smith %J Physics %D 2005 %I arXiv %R 10.1103/PhysRevC.72.058202 %X The polarized longitudinal-transverse structure function $\sigma_{LT^\prime}$ measures the interference between real and imaginary amplitudes in pion electroproduction and can be used to probe the coupling between resonant and non-resonant processes. We report new measurements of $\sigma_{LT^\prime}$ in the $N(1440){1/2}^+$ (Roper) resonance region at $Q^2=0.40$ and 0.65 GeV$^2$ for both the $\pi^0 p$ and $\pi^+ n$ channels. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at a beam energy of 1.515 GeV. Complete angular distributions were obtained and are compared to recent phenomenological models. The $\sigma_{LT^\prime}(\pi^+ n)$ channel shows a large sensitivity to the Roper resonance multipoles $M_{1-}$ and $S_{1-}$ and provides new constraints on models of resonance formation. %U http://arxiv.org/abs/nucl-ex/0504027v2