Determination of energy of nn-singlet virtual state in d+2H->p+p+n+n reaction

TL;DR

This study investigates the virtual state energy of the neutron-neutron system in a specific nuclear reaction, revealing an enhanced nn-interaction through experimental and simulation analysis.

Contribution

It provides a new measurement of the nn virtual state energy in the d+2H reaction, highlighting an effective enhancement of nn-interaction in the intermediate state.

Findings

Estimated nn virtual state energy: 0.076 +/- 0.006 MeV

Demonstrated dependence of neutron energy spectrum on nn virtual state energy

Indicated effective enhancement of nn-interaction in the reaction

Abstract

The nn final state interaction has been investigated in d+2H->(pp)S+(nn)S->p+p+n+n reaction going through a formation and breakup of singlet diproton and dineutron in the intermediate state. In the kinematically complete experiment performed at Ed =15 MeV two proton and neutron were detected at angles close to those of emission of (pp)S and (nn)S systems. Simulation of the reaction showed that the shape of neutron energy (timing) spectrum depends on epsnn - the energy of virtual 1S0 state of nn-system. The most likely value epsnn = 0.076 +/- 0.006 MeV was obtained by fitting procedure using the experimental data and simulations. This low value of epsnn evidently indicates on effective enhancement of nn-interaction in the intermediate state of studied reaction