ping
Posted on 12/12/2021 8:57:01 PM PST by BenLurkin
While all atomic nuclei except hydrogen are composed of protons and neutrons, physicists have been searching for a particle consisting of two, three, or four neutrons for over half a century. Experiments by a team of physicists of the Technical University of Munich (TUM) at the accelerator laboratory...now indicate that a particle comprising four bound neutrons may well exist.
Should such particle exist, parts of the theory of the strong interaction would need to be rethought.
In 2016, a group in Japan attempted to produce tetra-neutrons from helium-4 by bombarding it with a beam of radioactive helium-8 particles. This reaction should produce beryllium-8. In fact, they were able to detect four such atoms. From their measurement results, the researchers concluded that the tetra-neutron was unbound and quickly decayed back into four neutrons.
In their experiments, Faestermann and his team bombarded a lithium-7 target with lithium-7 particles accelerated to about 12 percent of the speed of light. In addition to the tetra-neutron, this should produce carbon-10. And indeed, the physicists succeeded in detecting this species. A repetition confirmed the result.
Circumstantial evidence The team’s measurement results matched the signature that would be expected from carbon-10 in its first excited state and a tetra-neutron bound by 0.42 megaelectronvolts (MeV). According to the measurements the tetra-neutron would be roughly as stable as the neutron itself. It would then decay by beta-decay with a half-life of 450 seconds. “For us, this is the only physically plausible explanation of the measured values in all respects,” explains Dr. Thomas Faestermann.
With their measurements, the team achieves a certainty of well over 99.7 percent, or 3 sigma. But in physics, the existence a particle is only considered conclusively proven once a certainty of 5 sigma is achieved. Thus, the researchers are now eagerly awaiting independent confirmation.
(Excerpt) Read more at scitechdaily.com ...
ping
Practical application?
Everything else in the universe is related and is a practical application. This is elucidating physical laws and the architecture of the universe.
I suspect this might be racist /s/
“Practical application?”
First step in building a neutron star!
This was already discovered 5 years ago.
https://www.asianscientist.com/2016/01/in-the-lab/tokyo-tetraneutron-proton/
January 11, 2016In the Lab
By Shern Ren Tee
Exotic ‘Four Neutron-No Proton’ Particle Confirmed
For the first time, researchers have confirmed the existence of a unique particle made up of four neutrons and no protons—the tetraneutron.
AsianScientist (Jan. 11, 2016) – Following the recent addition of four new elements to the periodic table, nuclear physics made headlines again as Japanese physicists announced the creation and discovery of the long-elusive tetraneutron particle. This research was published in Physical Review Letters.
Neutrons are surprisingly elusive particles and subjects of serious theoretical interest. They overcome the repulsion between protons to ‘glue’ the atomic nucleus together, as physicists have known for nearly a century now, and are thus crucial to understanding nuclear dynamics.
However, the lone neutron is unstable and takes only about fifteen minutes to decay into a proton. Furthermore, neutrons are not affected by electric and magnetic fields as they are electrically neutral, making them even harder to manipulate in the lab. Despite these experimental difficulties, neutron-neutron interactions are of great theoretical importance.
“Both very large atomic nuclei (where neutrons outnumber protons about three to two, on average) and neutron stars contain large clumps of neutrons, whose behavior remains very poorly understood,” explains Professor Susumu Shimoura, from the University of Tokyo Graduate School of Science.
The creation and discovery of multi-neutron states has attracted considerable attention in nuclear physics. In particular, the tetraneutron—four neutrons bound together, or temporarily bound in a metastable state—has been the subject of controversy, as various theoretical studies have disagreed on whether such a particle can even be formed.
“But now, our research group has demonstrated a method to produce and observe tetraneutron states, in collaboration with researchers at RIKEN and other institutions,” Shimoura continued. “We began by colliding a beam of oxygen ions with a beryllium target to produce a stream of highly unstable 8-helium nuclei, which were in turn directed at a second target of liquid helium.
“Whenever a pair of alpha particles was detected from these second collisions, simple counting dictated that four neutrons must have been left behind—but were they bound to each other as a single particle, or had they simply flown off in separate directions as debris?”
To answer this question, the researchers measured the energy of the emitted alpha particles, and confirmed that on many occasions the remainder of the energy could not have been enough to permit the neutrons to fly off independently. This confirmed that the four neutrons left behind were indeed bound into a tetraneutron particle.
The discovery of the tetraneutron raises important questions for nuclear physics. In particular, many theorists have proposed that it would require nuclear interactions between three or four particles simultaneously, instead of just acting between pairs of particles, which would require serious changes to our current understanding of nuclear forces.
Other possibilities—such as the tetraneutron as a loose bundle of smaller, more tightly-bound clusters—are being investigated, each of which would make different predictions for future experiments on the tetraneutron. In conclusion, this discovery sheds new light on nuclear science, and shows us that we still have much to learn about the humble neutron.
The article can be found at: Kisamori et al. (2015) Candidate Resonant Tetraneutron State Populated by the 4He(8He,8Be) Reaction.
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Copyright: Asian Scientist Magazine; Photo: Susumu Shimoura/University of Tokyo.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
#Editor’s Pick #Japan #Particle Physics #Tetraneutron #University of Tokyo
Shern Ren Tee
Shern Ren is studying towards a PhD degree in physics at the National University of Singapore. When he isn’t working on the statistical mechanics of nanomachines and single-molecule systems, you may find him scratching his head over politics, education and the mathematics of Threes.
If it only exists for 900 seconds and is shedding alpha particles, it could be a source of nuclear energy that doesn’t generate harmful radiation, at least not for very long. It could also explain why alpha particles are being detected in LENR experiments.
I thought so too. Turns out, Olivia Neutron John even recorded a song about it.
The article does not mention an important result. What becomes of the tetra neutron? It says it has a beta decay. Does it become Hydrogen 4? I suspect it would have a double beta decay and become an alpha particle since that is a particularly stable configuration.
I suspect, having been there and done that, that this will eventually become another of the all-to-frequent-disappearing discoveries of the last 40-years in fundamental physics...
Lol
Read later.
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