Data on neutron-neutron scattering length extracted in the n+2H-->n+n+p reaction at 60 MeV

TL;DR

This paper reports a precise measurement of the neutron-neutron scattering length at 60 MeV using the nd-breakup reaction, confirming the influence of three-nucleon forces on nn-interaction parameters.

Contribution

The study provides a new experimental value of the nn-scattering length and analyzes its consistency with other data, highlighting the role of three-nucleon forces.

Findings

nn-scattering length measured as -16.3 ± 0.5 fm

Data supports the influence of 3N-forces on nn-interaction

Results are consistent with previous nd- and dd-breakup experiments

Abstract

$^{1}S_{0}$ \textit{nn}-scattering length has been measured in the \textit{nd}-breakup reaction at 60 MeV. The experiment was performed in the final state interaction geometry with registration of all three secondary particles. The scattering length $a_{nn} = -16.3 \pm 0.5$~fm was obtained from a comparison of the experimental dependence of the \textit{nd}-breakup yield on the relative energy of \textit{nn}-pair with the simulation results. An analysis of this value of scattering length together with the data obtained in other experiments on \textit{nd}- and \textit{dd}-breakup confirms the hypothesis about the influence of $3N$-forces on the values of \textit{nn}-interaction parameters extracted in these reactions.