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arXiv 0908.0848nucl-th
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EBAC @ JLAB π介子的单光子和电产生

Single photo and electroproduction of pions at EBAC@JLAB

B. Julia-Diaz

备注：
6 pages, invited talk at NSTAR 2009, Beijing (China), 2009, to appear in the proceedings
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摘要：

在激发重子分析中心，我们对$W \leq $ 1.6 GeV和$Q^2 \leq$ 1.45（GeV/c）$^2$区域的可用$p(e,e' π)N$数据进行了动力学耦合道分析。包括的通道是$γ^* N$、$πN$、$ηN$和$ππN$，后者具有$πΔ$、$ρN$和$σN$组件。利用我们以前对$πN\to πN$反应研究中确定的模型强子参数，我们发现在所考虑的$W \leq $ 1.6 GeV区域内，只需要调整$P_{33}$，$P_{11}$，$S_{11}$和$D_{13}$分波中最低$N^*$态的裸$γ^* N \to N^*$螺旋度振幅就可以很好地拟合现有的数据。根据么正性条件的要求，研究了介子云效应对$γ^* N \to N^*$形状因子的影响.

英文摘要：

Within the Excited Baryon Analysis Center we have performed a dynamical coupled-channels analysis of the available $p(e,e' π)N$ data in the region of $W \leq $ 1.6 GeV and $Q^2 \leq$ 1.45 (GeV/c)$^2$. The channels included are $γ^* N$, $πN$, $ηN$, and $ππN$ which has $πΔ$, $ρN$, and $σN$ components. With the hadronic parameters of the model determined in our previous investigations of $πN\to πN$ reaction, we have found that the available data in the considered $W \leq $ 1.6 GeV region can be fitted well by only adjusting the bare $γ^* N \to N^*$ helicity amplitudes for the lowest $N^*$ states in $P_{33}$, $P_{11}$, $S_{11}$ and $D_{13}$ partial waves. The meson cloud effect, as required by the unitarity conditions, on the $γ^* N \to N^*$ form factors are examined.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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