Can Tetraneutron be a Narrow Resonance?

Area of Science:

• Nuclear Physics
• Quantum Mechanics
• Computational Physics

Background:

• Recent experimental hints suggest the possibility of a resonant four-neutron system.
• The existence of a four-neutron system would significantly alter our understanding of nuclear matter.

Purpose of the Study:

• To investigate the existence of a four-neutron resonance using ab initio techniques.
• To critically assess experimental observations regarding the four-neutron system.

Main Methods:

• Utilized the quasistationary formalism with ab initio techniques.
• Employed the no-core Gamow shell model and density matrix renormalization group method.
• Incorporated natural orbitals and a novel technique for identifying broad resonances.

Main Results:

• Calculated energy for the four-neutron system is compatible with experimental values.
• The calculated width of the four-neutron system significantly exceeds the experimental upper limit.
• The findings challenge the interpretation of the experimental hints as a stable four-neutron resonance.

Conclusions:

• The study suggests that the experimental observation is more likely a short nuclear reaction process rather than the formation of a four-neutron nucleus.
• Further theoretical and experimental investigations are needed to fully understand the nature of the four-neutron system.