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

N. F. Sparveris; P. Achenbach; C. Ayerbe Gayoso; D. Baumann; J. Bernauer; A. M. Bernstein; R. Böhm; D. Bosnar; T. Botto; A. Christopoulou; D. Dale; M. Ding; M. O. Distler; L. Doria; J. Friedrich; A. Karabarbounis; M. Makek; H. Merkel; U. Müller; I. Nakagawa; R. Neuhausen; L. Nungesser; C. N. Papanicolas; B. Pasquini; A. Piegsa; J. Pochodzalla; M. Potokar; M. Seimetz; S. Širca; S. Stave; S. Stiliaris; Th. Walcher; M. Weis

doi:10.1103/physrevc.78.018201

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arXiv · 0804.1169

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

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Abstract

We report on new H$(e,e^\prime p)γ$ measurements in the $Δ(1232)$ resonance at $Q^2=0.06$ (GeV/c) carried out simultaneously with H$(e,e^\prime p)π^0$. 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$(e,e^\prime p)π^0$ data are used as input, thus confirming the compatibility of the results. The derived resonant magnetic dipole amplitude $M^{3/2}_{1+} = (40.60 \pm 0.70_{stat+sys})(10^{-3}/m_{π^+})$ at $W=$ 1232 MeV is in excellent agreement with the value extracted from H$(e,e^\prime p)π^0$ measurements.

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N. F. Sparveris, P. Achenbach, C. Ayerbe Gayoso, D. Baumann, J. Bernauer, A. M. Bernstein, R. Böhm, D. Bosnar, T. Botto, A. Christopoulou, D. Dale, M. Ding, M. O. Distler, L. Doria, J. Friedrich, A. Karabarbounis, M. Makek, H. Merkel, U. Müller, I. Nakagawa, R. Neuhausen, L. Nungesser, C. N. Papanicolas, B. Pasquini, A. Piegsa, J. Pochodzalla, M. Potokar, M. Seimetz, S. Širca, S. Stave, S. Stiliaris, Th. Walcher, M. Weis. 2008-04-08. Virtual Compton Scattering measurements in the $γ^* N\to Δ$ transition. https://doi.org/10.1103/physrevc.78.018201

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