2005/05/23 by J. J. Kelly, James J. Kelly, R. Roché +81 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #nucl-ex
paper · pdf · doi:10.1103/physrevlett.95.102001
published as Phys.Rev.Lett.95:102001,2005 · 5 pages, 2 figures, for PRL
arxiv created 2005/05/23 · openalex publication_date 2005/08/29 · arxiv updated 2010/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/02
We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q2=1.0 (GeV/c)2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S1+/M1+)=\ensuremath-(6.84\ifmmode±\else\textpm\fi0.15)% and Re (E1+/M1+)=\ensuremath-(2.91\ifmmode±\else\textpm\fi0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and \ensuremathℓ_\ensuremathπ\ensuremath≤1 truncation.