Critique on "Universal Theory of Primary Interactions and Nucleon-Nucleon Scattering"

We remark on a calculation of low-energy nucleon-nucleon scattering carried out by Chiang, Gleiser, Huq, and Saxena, who use Sudarshan's "universal vector and axial-vector interaction theory" in a one-boson-exchange potential approximation. We show that the test of high-mass meson exchange forces comes in fitting the lower partial waves ($l\le 2$), not in fitting the higher partial waves ($l\ge 3$), since mere one-pion exchange accounts for most of the observed scattering in the higher partial waves. Thus Chiang et al.'s admittedly poor fit to some of the lower partial waves would seem to disprove Sudarshan's model. However, we point out an error in the treatment of the one-$\rho$-exchange potential, the correction of which will significantly improve the fit to the data, although the over-all agreement will still be poor. We also point out that Sudarshan's assumption, that the $\omega$-nucleon coupling constant equals the $\rho$-nucleon coupling constant, is both arbitrary and in conflict with experiment, and that if $g_{\omega }^{}{}_{}{}^2$ is altered to agree with experiment, the model will be in considerably better agreement with experiment. Finally, we remark that the model also lacks sufficient intermediate-range attraction, but that this is due in part to the neglect of the two-pion-exchange terms in Chiang et al.'s calculation. With the inclusion of $2\pi$ effects, the Sudarshan model should correctly predict the qualitative features of low-energy nucleon-nucleon scattering. However, a precise fit will likely require the exchange of the $\epsilon (715,T=0,J=0^{+})$, and Sudarshan's model makes no provision for such a meson.