We just took a step closer to solving the mysteries of the universe.
A team of researchers has achieved the most accurate measurement of the lifespan of a neutron, according to a study recently shared with a prepress server.
However, the discrepancy between the measurement methods remains unresolved.
The most accurate measurement of neutron decay
Neutrons are a type of particle that usually stays inside atoms. They have existed for billions of years longer in some of the atoms that make up the cosmos, but when separated from the atom, they begin to decay into protons and other, more basic particles. And, separated from their host atoms, neutrons last only about 15 minutes. Physicists have been trying to measure the exact life of a neutron for decades, using mostly two techniques. The first uses bottles and the second uses beams. But the results of the two do not match, showing a difference of 9 seconds – an eternity in atomic time frames and significant in our own, as we are talking about a particle that “lives” only 15 minutes.
However, the new study was able to find the most accurate measurement of neutron life with the bottle technique. The experiment, called UCNtau (or Ultra Cold Neutrons tau, the latter of which means the life of neutrons), also revealed that a neutron lives exactly 14,629 minutes, with an uncertainty of approximately 0.005 minutes. Incredibly, this is twice as accurate as previous measurements made with both methods. The latest results do not solve the enduring mystery of why the results for the bottle and beam methods are incommensurable, but they brought us one step closer to the real answer. “This new result provides an independent assessment to help solve the puzzle of neutron life,” said Francis L. Mosley, a physics professor at Caltech’s co-author of the recent study, in university post.
Unraveling the mysteries of the early universe
The two methods continue to show inconsistencies, but Philippon believes that this is either because one of them may be defective, or because there is something in physics that awaits our future discovery. “Combined with other precise measurements, this result can provide much-sought evidence for the discovery of new physics,” he added. The results can also shed light other enduring mysteries of physics, just as matter in the early universe first escaped the unconsciously hot soup of neutrons and extra particles. “Once we know exactly the life of neutrons, this may help explain how atomic nuclei form in the first minutes of the universe.”
The UCNtau team conducted two bottle experiments in 2017 and 2018 at the National Laboratory in Los Alamos (LANL). During the bottle method, the free neutrons are contained in an ultra-cold and magnetized bottle that is approximately the size of a bath. Once trapped, neutrons begin to decay into protons. Highly advanced data analysis methods allow researchers to count how many neutrons remain with the passage of seconds. Conversely, the beam method uses a literal beam of neutrons that decays into protons, where protons are counted instead of neutrons. The UCNtau collaboration has counted a staggering 40 million neutrons since the experiments began, according to a publication by the California Institute of Technology. And since additional characteristics of neutrino decay and inconsistency between measurement methods are revealed, little more of the universe will unfold.