摘要: The η meson (sometimes called the χ) was discovered by Pevsner et al. (1961) looking at interactions of pions momentum 1.23GeV/c in a deuterium bubble chamber.
N. Gelfand, D. Miller, M. Nussbaum, J. Ratau, J. Schultz, J. Steinberger, T. -H. Tan, L. Kirsch, R. Plano, LIFETIME OF THE $omega$ MESONPhysical Review Letters. ,vol. 11, pp. 436- 438 ,(1963) , 10.1103/PHYSREVLETT.11.436