Observation of a correlated free four-neutron system - Nature.com

Experiment based on knocking out an alpha particle from a high-energy helium isotope shows a resonance-like structure that is consistent with a quasi-bound tetraneutron state existing for a very short time.

A neutron can be bound either in an atomic nucleus or in a neutron star. The free neutron has a lifetime of just under 15min and decays into a proton, electron and antineutrino. The system made of tw… [+23639 chars]

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