Far out cosmology: why matter? (Introduction)

by David Turell , Thursday, April 16, 2020, 19:36 (1680 days ago) @ David Turell

The neutrino experiments must go on; an editorial comment:

https://www.nature.com/articles/d41586-020-01022-3?WT.ec_id=NATURE-20200416&utm_sou...

"Using these data, the T2K collaboration measured the probability that a neutrino would oscillate between different physical properties that physicists call ‘flavours’ during its journey. The team then ran the same experiment with antineutrinos, and compared the numbers. If matter and antimatter are perfectly symmetrical, the probabilities should be the same.

"The results, however, suggest they are not. T2K detected a higher probability that neutrinos would change flavour during their 300-km journey — and a correspondingly lower probability for antineutrinos — than would be expected if they behaved identically.

"Such a finding, if it can be confirmed, lends weight to Sakharov’s explanation from 1967 that matter and antimatter have different properties. But there’s a caveat: the current finding does not satisfy the required level of confidence — known as 5-sigma (5σ) — that particle physicists would typically demand to consider the result a discovery. The present T2K results are at a 3σ level of statistical significance — and this drops to 2σ if matter–antimatter symmetry is to be ruled out entirely.

"Even so, it’s important to publish such fundamental work as it progresses. Experiments in particle physics can take decades to be planned and built, so results that are not yet at the 5σ significance have a crucial role in informing the community’s decisions on future investments.

"The researchers could have waited longer. But even if they had, the T2K experiment is unlikely to have provided the additional data required to cross the 5σ finishing line. To get to 5σ, physicists will need results from the next generation of neutrino detectors.

"Fortunately, there are three such detectors due to come on stream: Hyper-Kamiokande, located near Super-Kamiokande, expected to start in 2027; DUNE in the United States, due to start in 2025; and JUNO in China, which aims to be the first of the three to go live, in 2022.

"Time will tell if these preliminary observations hold. But at a time when big investments in high-energy physics are coming under increased scrutiny, this result reinforces the importance of continuing to search for answers to some of the Universe’s deepest mysteries."

Comment: Deep mysteries take lots of time to solve. An example of five sigma is: .00006 odds it correct. God works in very mysterious or necessary ways.