1. Observation of a correlated free four-neutron system  Nature.com
  2. Physicists may have finally spotted elusive clusters of four neutrons  Science News Magazine
  3. Theoretical calculations predicted now-confirmed tetraneutron, an exotic state of matter  Phys.org
  4. Elusive exotic matter called a tetraneutron possibly seen in the lab  New Scientist
  5. Collisions hint that four neutrons form a transient isolated entity  Nature.com
  6. View Full coverage on Google News
A long-standing question in nuclear physics is whether chargeless nuclear systems can exist. To our knowledge, only neutron stars represent near-pure neutron systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron systems has been an ongoing quest for several decades1, with a particular focus on the four-neutron system called the tetraneutron, resulting in only a few indications of its existence so far2–4, leaving the tetraneutron an elusive nuclear system for six decades. Here we report on the observation of a resonance-like structure near threshold in the four-neutron system that is consistent with a quasi-bound tetraneutron state existing for a very short time. The measured energy and width of this state provide a key benchmark for our understanding of the nuclear force. The use of an experimental approach based on a knockout reaction at large momentum transfer with a radioactive high-energy 8He beam was key. 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.Nature - 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...

Observation of a correlated free four-neutron system | Nature

Long-sought clumps of four neutrons called tetraneutrons last less than a billionth of a trillionth of a second, an experiment suggests.

Physicists may have finally spotted elusive clusters of four neutrons | Science News

James Vary has been waiting for nuclear physics experiments to confirm the reality of a "tetraneutron" that he and his colleagues theorized, predicted and first announced during a presentation in the ...

Theoretical calculations predicted now-confirmed tetraneutron, an exotic state of matter

Twenty years ago, researchers saw hints of the existence of a type of exotic matter made of four neutrons. Now, researchers have found the clearest evidence it exists yetTwenty years ago, researchers saw hints of the existence of a type of exotic matter made of four neutrons. Now, researchers have found the clearest evidence it exists yet

Elusive exotic matter called a tetraneutron possibly seen in the lab | New Scientist