Modern nuclear force predictions for $n-{}^3\mathrm{H}$ scattering above the three- and four-nucleon breakup thresholds

Background: Description of the collision process, which includes breakup, is one of the most challenging problems of the quantum mechanics. Recently I have developed a formalism based on the complex-scaling method, which describes accurately nuclear collisions in three- and four-body systems.

Purpose: To provide accurate calculations for $n-{}^3\mathrm{H}$ scattering above the three- and four-nucleon breakup thresholds.

Method: A four-nucleon system is described in configuration space employing Faddeev-Yakubovsky equations. The complex-scaling method is applied to overcome the difficulties related with the complicated boundary conditions.

Results: Elastic observables as well as total breakup cross sections are calculated for neutron scattering on tritium at 14.1, 18, and 22.1 MeV using realistic $\mathit{NN}$ interactions. Excellent agreement is found with the pioneering calculations of this process reported by A. Deltuva et al. [Phys. Rev. C 86, 011001 (2012)]. Strong correlation of the calculated cross sections is established with model-predicted trinucleon binding energy. The forementioned observables reveal little sensitivity to the short-range details of $\mathit{NN}$ interaction.

Conclusion: Reliable and accurate methods are now available to study four-nucleon scattering including the breakup.

Figure 1

The FY components $K_{12,3}^4$ and $H_{12}^{34}$. As $z\to \infty$, the $K$-type components describe 3 + 1 particle channels, while the $H$-type components contain asymptotic states of 2 + 2 channels.

Figure 2

Calculated $n-{}^3\mathrm{H}$ elastic differential cross sections (left panel) and neutron analyzing power $A_y$ (right panel) for incident neutrons at laboratory energy 22.1 MeV. Calculated values are compared with the experimental results of Seagrave et al. [28].

Figure 3

Dependence of the calculated $n-{}^3\mathrm{H}$ total elastic and inelastic (breakup) cross sections on the triton binding energy. Calculations have been performed for neutrons with laboratory energy of 22.1 MeV.