Comment on Yuan Et Al

It has come to our attention that the work of Yuan et al. [1] is being represented as definitive regarding the existence of a particular nonstrange, isoscalar, spin three dibaryon, d * , which we [2] , among others [3, 4, 5, 6, 8] , have proposed exists. We therefore wish to comment on this paper and its relation to ours and those of others. In our work [2] , the d * dibaryon is constructed in terms of its constituent quark wavefunctions, which include significant distortion from those found in isolated baryons. It should be noted that these wavefunctions do not collapse into a simple, spherical system as proposed, for example, by Jaffe [9] for the H dibaryon. Our techniques have allowed us to demonstrate that this picture adequately reproduces known low energy baryon-baryon scattering amplitudes with only one or two fitting parameters. At the other extreme are theories of baryon interactions without any quark sub-structure whatsoever. These also, in terms of effective potentials or meson exchanges, adequately reproduce known low energy baryon-baryon scattering amplitudes, albeit with a multitude of fitting parameters. Such approaches tend not to predict deeply bound dibaryons, with the exception of Ref.[6]. Rather, the states examined are generally found to have a character not very dissimilar from the deuteron, with small binding energies predicted [10] , if any. Approaches such as that of Yuan et al. [1] and similarly those of Thomas et al. or Wilets et al. [7] take an intermediate view, including quark substructure of distinct baryons, but variously restricting interactions between quarks as due to exchanges of mesons or other collective fields, exchanges of gluons, or both. Some change of internal baryon structure is allowed in these models. Interestingly, the approaches that include or are restricted to only meson exchanges may be characterized as generally predicting dibaryon states with binding energies intermediate between the two approaches referred to above. They also can well describe low energy baryon-baryon scattering amplitudes or nuclei, albeit again with a significant number of parameters which must be fit to data.