Virtual Compton Scattering measurements in the $γ^* N\to Δ$ transition

Abstract

We report on new H$(e,e^{\prime }p){\hat{I}}^3$ measurements in the $\hat{I}”(1232)$ resonance at $Q^2=0.06$ (GeV/c) carried out simultaneously with H$(e,e^{\prime }p)\ddot{I}{€}^0$. It is the lowest $Q^2$ for which the virtual Compton scattering (VCS) reaction has been studied in the first resonance region. The VCS measured cross sections are well described by dispersion-relation calculations in which the multipole amplitudes derived from H$(e,e^{\prime }p)\ddot{I}{€}^0$ data are used as input, thus confirming the compatibility of the results. The derived resonant magnetic dipole amplitude $M_{1+}^{3/2}=(40.60\pm 0.70_{stat+sys})(10^{-3}/m_{\ddot{I}{€}^{+}})$ at $W=$ 1232 MeV is in excellent agreement with the value extracted from H$(e,e^{\prime }p)\ddot{I}{€}^0$ measurements.

4 pages, 4 figures