ИСТИНА

The precise determination of parameters of neutron-neutron interaction, in particular, nn scattering length, is an important problem in nuclear physics for many reasons. However, almost all information about nn interaction one need to extract from the Nd scattering data, where such information is often model-dependent, e.g., it depends on the suggested form of three-body forces. So, it is more reliable to consider for extraction of nn parameters the Nd elastic scattering in forward hemisphere where effects of three-body forces are almost negligible. We used analytical formulas obtained in our previous work within the refined Glauber model. These formulas which relate all the twelve Nd invariant amplitudes to the input Np and Nn helicity amplitudes allowed to develop an efficient and convenient algorithm for solving an inverse scattering problem (at fixed energy). Before doing the inversion we examined the sensitivity of Nd cross sections and spin analyzing powers to the input NN helicity amplitudes with taking into consideration experimental error corridor. The applications of the algorithm are explicitly formulated as follows: (i) Having the precise intermediate-energy nd spin observables and differential cross section and by taking the respective np helicity amplitudes at the same energy as a well established input one can reconstruct poorly known neutron-neutron scattering amplitudes at the same energy. (ii) Having in our possession the accurate pd experimental data and the pp helicity amplitudes in the energy region Tp > 1.1 GeV one can find by inversion neutron-proton scattering amplitudes which are still poorly known at these energies. Combining items (i) and (ii) one can eventually obtain the nn and np scattering amplitudes up to the highest energy achieved in pp phase shift analysis (currently it is equal to 3 GeV in lab. system). So, the refined Glauber model with its transparent analytical formulas opens a way to finding in principle the accurate nn (or np) scattering amplitudes and phases from the precise nd (or pd) experimental data in a model-independent way.