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تسجيل مستخدم جديدMAID Analysis Techniques
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MAID is a unitary isobar model for a partial wave analysis of pion photo- and electroproduction in the resonance region. It is fitted to the world data and can give predictions for multipoles, amplitudes, cross sections and polarization observables in the energy range from pion threshold up to W=2 GeV and photon virtualities Q^2 < 5 GeV^2. Using more recent experimental results from Mainz, Bates, Bonn and JLab for Q^2 up to 4.0 GeV^2, the Q^2 dependence of the helicity couplings A_{1/2}, A_{3/2}, S_{1/2} has been extracted for a series of four star resonances. We compare single-Q^2 analyses with a superglobal fit in a new parametrization of Maid2005. Besides the (pion) MAID, at Mainz we maintain a collection of online programs for partial wave analysis of eta, eta and kaon photo- and electroproduction which are all based on similar footings with field theoretical background and baryon excitations in Breit-Wigner form.
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The unitary isobar model MAID2007 has been used to analyze the recent data of pion electroproduction. The model contains all four-star resonances in the region below W=2 GeV and both single-Q^2 and Q^2 dependent transition form factors could be obtai
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