True parameters of He-4-Sigma hypernucleus
It is shown that the true parameters of He-4-Sigma differ from the observed ones. The reason is that the amplitude of He-4-Sigma production in the reaction He-4(K-,pi-) sharply varies just in the corresponding mass region. It leads to the small, but noticeable shift of the binding energy and the width. Besides, the data at the threshold of Sigma-0 production is found to give an additional evidence that He-4-Sigma width cannot exceed 8.0 - 8.5 MeV.