【摘 要】
:
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
【机 构】
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Institut für Kernphysik,Bogoliubov Laboratory for Theoretical Physics
【基金项目】
:
Deutsche Forschungsgemeinschaft through SFB 443 and joint Russian-German Heisenberg-Landau program
论文部分内容阅读
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 obtained for the Delta, Roper, D_(13)(1520), S_(11) (1535), S_(31) (1620), S_(11)(1650), D_(15)(1675), F_(15)(1680) and P_(13)(1720). From the complete world data base, including also π~- data on the neutron, also Q~2 dependent neutron form factors are obtained. For all transition form factors we also give convenient numerical parameterizations that can be used in other reactions. Furthermore, we show how the transition form factors can be used to obtain empirical transverse charge densities and our first results are given for the Roper, the S_(11) and D_(13) resonances.
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