相对动量 meaning in English

relative momentum

The relative momentum of two final particles and the cross section are zero at the threshold energy for an endothermic reaction , while the relative momentum of two initial particles is zero and the cross section at the threshold energy for an exothermic reaction is infinite
在吸热反应的阈能处，出射粒子的相对动量以及截面均为零。在放热反应的阈能处，入射粒子的相对动量为零，截面趋于无穷大。由于强子的动量仅提供如此低的质心系能量，强子物质中x 。