Near-threshold η production in pp collisions

作者：Lu Qi-Fang; Li De-Min

来源：Chinese Physics C, 2015, 39(11): 113104.

DOI：10.1088/1674-1137/39/11/113104

• effective Lagrangian approach
• isobar model
• nucleon resonances

We study near-threshold eta meson production in pp collisions within an effective Lagrangian approach combined with the isobar model, by allowing for the various intermediate nucleon resonances due to the pi, eta, and rho-meson exchanges. It is shown that the rho-meson exchange is the dominant excitation mechanism for these resonances, and the contribution from the N* (1720) is dominant. The total cross section data can be reasonably reproduced, and the anisotropic angular distributions of the emitted eta meson are consistent with experimental measurements. Besides, the invariant mass spectra of pp and p eta explain the data well at excess energy of 15 MeV, and are basically consistent with the data at excess energy of 40 MeV. However, our model calculations cannot reasonably account for the two-peak structure in the p eta distribution at excess energies of 57 and 72 MeV, which suggests that a more complicated mechanism is needed at higher energy region.

• 出版日期2015-11
• 单位郑州大学