双中性浦胎光生源中的极化可观察力

论文标题

双中性浦胎光生源中的极化可观察力

Polarization observables in double neutral pion photoproduction

论文作者

TAPS Collaboration, Seifen, T., Hartmann, J., Afzal, F., Anisovich, A. V., Beck, R., Becker, M., Berlin, A., Bichow, M., Brinkmann, K. -Th., Crede, V., Dieterle, M., Dutz, H., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Grüner, M., Görtz, St., Gutz, E., Hammann, Ch., Hannappel, J., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Lang, M., Mahlberg, Ph., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Müllers, J., Nanova, M., Nikonov, K., Nikonov, V. A., Novotny, R., Reeve, S., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A. V., Schmidt, Ch., Schmieden, H., Schmitz, R., Schultes, J., Sokhoyan, V., Stausberg, N., Thiel, A., Thoma, U., Urban, M., Urff, G., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Witthauer, L., Wunderlich, Y.

论文摘要

报告了对反应$γp\至pπ^0π^0 $的目标不对称和双极化的测量。这些数据是使用Bonn Frozen-Spin丁醇（C $ _4 $ H $ _9 $ OH）的CBELSA/TAPS实验在ELSA设施（波恩大学）进行的，该目标提供了横向极化的质子。线性极化的光子是通过钻石晶体从Bremsstrahung生产的。数据涵盖了光子能量范围从$e_γ$ = 650 meV到$e_γ$ = 2600 meV，几乎是完整的角范围。结果已包括在BNGA部分波分析中。实验结果和拟合度非常吻合。观察到的分支比率的系统差异$ n^*$和$δ^*$共振归因于这些激发核子状态的内部结构。可以分配给SU（6）$ \ times $ o（3）的两个振荡器配置的共振显示出比分配给单振荡器配置的共振的非零内轨道角度矩形的中间状态更大的分支比率。

Measurements of target asymmetries and double-polarization observables for the reaction $γp\to pπ^0π^0$ are reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility (Bonn University) using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided transversely polarized protons. Linearly polarized photons were produced via bremsstrahlung off a diamond crystal. The data cover the photon energy range from $E_γ$=650 MeV to $E_γ$=2600 MeV and nearly the complete angular range. The results have been included in the BnGa partial wave analysis. Experimental results and the fit agree very well. Observed systematic differences in the branching ratios for decays of $N^*$ and $Δ^*$ resonances are attributed to the internal structure of these excited nucleon states. Resonances which can be assigned to SU(6)$\times$O(3) two-oscillator configurations show larger branching ratios to intermediate states with non-zero intrinsic orbital angular momenta than resonances assigned to one-oscillator configurations.

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