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Compositeness was introduced by Steven Weinberg in 1967 to address that whether Deuteron is a composite particle. This quantity finds its new usage in the study of Exotic hadrons. Lambda(1405) was successfully explained by a Kbar-N scattering state. Sekihara et.al. gave compositeness a more formal framework. However, we found that the methods stated above results in a larger than one compositeness for deuteron. Since compositeness is the proportion of the bound state composed by scattering state, this outcome seems to be unphysical. This outcome was interpreted as insufficient higher order terms by S. Weinberg. We concluded that this higher than 1 compositeness cannot be an outcome of other states or channels. We also found that energy dependence that cannot be attributed to other states or channels will result in a modification to the theory, and cut off the connection from experiment to compositeness. Thus, a higher than 1 compositeness from weak-binding limit calculation indicates that the original assumption may not hold, and model-independent calculation becomes inappropriate. We suggest that an inclusion of three body state will fix this problem.
