S.I. Bilen'kaya

THE PROBLEM OF THE UNAMBIGUITY OF PHASE-SHIFT ANALYSIS. II. N--N SCATTERING PHASE-SHIFT ANALYSIS AT ENERGIES NEAR TO 20 MeV.

The new results of phase-shift analysis at energies of 23·1 and 18·2 MeV are discussed. Two and three solutions remain at these energies respectively. The measurements of triple n-p scattering parameters are necessary for obtaining the unambiguity of the solutions. It is shown that the Berkeley p-p polarization data at 19·7 MeV are in disagreement with other results.For the discrimination of phase shift solutions the so-calledτ-criterion (described in Part I) was used.

The problem of the unambiguity of phase-shift analysis II

For the discrimination of phase-shift solutions, the new so-calledτ-criterion, based on the calculation of some functionτ of the experimental data, is used. This method can be applied, in general, to an arbitrary ambiguous phase-shift analysis. Theτ-criterion is more powerful than theχ2-criterion, e.g. for rejecting a less probable set it is necessary to have a smaller quantity of experimental points (in statistics this means that theτ-criterion gives a smaller Type II error). For the calculation of the quantityτ, the standard programme for phase-shift analysis with a small additional part can be used. A computer time of about only 5–10 min. on a computer of M-20 type is needed. A Type I error is then obtained from the tables of the normal distribution function.