标题： 在辐射J/psi→gamma p pbar衰变的p pbar质量谱中观察到近阈值增强现象 显示英文标题

标题： Observation of a near-threshold enhancement in th p pbar mass spectrum from radiative J/psi-->gamma p pbar decays

摘要： 我们在辐射J/psi-->gamma ppbar衰变中ppbar对的不变质量谱中观察到接近2mp的窄增强。 该增强可以用S波或P波Breit Wigner函数进行拟合。 在S波拟合的情况下，峰值质量低于2mp阈值，总宽度小于30 MeV。 这些质量和宽度值与任何已知介子共振的特性不一致。 显示英文摘要

摘要： We observe a narrow enhancement near 2mp in the invariant mass spectrum of ppbar pairs from radiative J/psi-->gamma ppbar decays. The enhancement can be fit with either an S- or P-wave Breit Wigner fuction. In the case of the S-wave fit, the peak mass is below the 2mp threshold and the full width is less than 30 MeV. These mass and width values are not consistent with the properties of any known meson resonance.