标题： 质子-质子反应中前向1S0双质子产生的能量依赖性 显示英文标题

标题： Energy dependence of forward 1S0 diproton production in the pp -> pp pi0 reaction

摘要： 质子对 ->{pp}_s π0 微分截面已用ANKE光谱仪在COSY-Juelich对七个质子束能量T_p在0.5到1.97 GeV之间进行了测量。 通过选择激发能小于3 MeV的质子对，可以确保最终的{pp}_s系统处于1S0态。 在测量的theta_{pp}^{厘米}< 18度区域内，数据揭示了当T_p <= 1.4 GeV时的前向凹陷，而在1.97 GeV时观察到前向峰值。 前向截面的能量依赖性在0.6-0.8 GeV区域显示出一个宽峰，可能与Delta(1232)激发有关，并在1.4 GeV处有一个最小值。 这些特征中的一些与观察到的自旋同位旋共轭反应pp -> d π+相似。 然而，这两个反应的前向微分截面的比值显示了与自旋单态最终核子对相关的单π介子产生显著抑制。 显示英文摘要

摘要： The pp -> {pp}_s pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for seven proton beam energies T_p between 0.5 and 1.97 GeV. By selecting proton pairs with an excitation energy of less than 3 MeV it is ensured that the final {pp}_s system is in the 1S0 state. In the measured region of theta_{pp}^{cm} < 18 deg, the data reveal a forward dip for T_p =< 1.4 GeV whereas a forward peaking is seen at 1.97 GeV. The energy dependence of the forward cross section shows a broad peak in the 0.6-0.8 GeV region, probably associated with Delta(1232) excitation, and a minimum at 1.4 GeV. Some of these features are similar to those observed for the spin-isospin partner reaction, pp -> d pi+. However, the ratio of the forward differential cross sections of the two reactions shows a significant suppression of single pion production associated with a spin--singlet final nucleon pair.