Tetraneutron resonance in the presence of a dineutron

Abstract

Background: Several previous studies provided contradicting results for the four-neutron system, some claiming the existence of a 0+ near-threshold resonance, others denying presence of any observable resonant states. Purpose: Since most of the studies employed enhanced two-neutron interactions to follow the evolution of an artificially bound state into a continuum one, we examine several enhancement schemes that produce a bound dineutron as well. Methods: We study the four-neutron system by solving exact four-particle equations. By varying the interaction enhancement factor we calculate two-dineutron scattering phase shifts and cross sections. Results: When the same enhancement factor is used in all partial waves, a bound tetraneutron emerges together with a strongly bound dineutron. Furthermore, such a 0+ tetraneutron evolves not into a resonance but into a virtual state. Weak enhancement of S waves together with strongly enhanced higher waves is needed for the emergence of the resonant state. Anyhow the resonant behavior disappears well before reaching the physical interaction strength. Conclusions: The interaction enhancement scheme using the same factor for all waves, employed in several previous works, is misleading for the search of 0+ resonance as only a virtual state can emerge. Evolution of a bound tetraneutron into a resonance via an intermediate virtual state is possible with strong enhancement of higher two-neutron waves.

6 pages, 7 figures, to be published in Phys. Rev. C

References in corpus (4)

• Prediction for a four-neutron resonance
• Can realistic nuclear interactions tolerate a resonant tetraneutron ?
• Three-neutron resonance trajectories for realistic interaction models
• Universality in fermionic dimer-dimer scattering

Cited by in corpus (9)

• The quest for light multineutron systems
• Non-resonant Density of States Enhancement at Low Energies for Three or Four Neutrons
• Low energy structures in nuclear reactions with 4n in the final state
• A Comprehensive Study of the Three- and Four-Neutron Systems at Low Energies
• Few-body bound states and resonances in finite volume
• Hadrons and Few-Body Physics
• The excited state of the $\alpha$-particle: a benchmark study
• Searching for the Tetraneutron Resonance on the Lattice
• The extremes of neutron richness