For matter to exist, the matter/anti-matter symmetry must be broken, or there would just be energy. But how is this done... and age-old question, but we may be closer to finding a good answer, if not the answer, and at the heart of it, at the moment, are neutrinos. This is a long article, but very worth reading all of it, so I am just cutting to the chase:
The scientists running the T2K experiment alternate between sending muon neutrinos and muon antineutrinos — measuring them as they depart Tokai and then measuring them again on arrival in Kamioka, to see how many have changed into regular old electron neutrinos. If nature and neutrinos are playing by the same old-fashioned symmetrical rules, the same amount of change should appear in both beams.
On Wednesday, in the abstract to a rather statistically dense paper, the authors concluded: “Our results indicate CP violation in leptons and our method enables sensitive searches for matter-antimatter asymmetry in neutrino oscillations using accelerator-produced neutrino beams.”
Asked to summarize the result, Dr. Sánchez, a team spokesman, said, “In relative terms more neutrino muons going to neutrino electrons than antineutrino muons going to antineutrino electrons.”
In other words, matter was winning.
This was a step in the right direction but, Dr. Sánchez cautioned, not enough to guarantee victory in the struggle to understand our existence. The big thing, he said, is that the experiment has definitely shown that the neutrinos violate the CP symmetry. Whether they violate it enough is not yet known.
“For a long time theorists have been discussing if CP violation in neutrinos would be enough,” Dr. Sánchez said. “The general agreement now is that it does not seem to be sufficient. But this is just modeling, and we might be wrong.”
More and larger experiments are in the works. Among them is the Deep Underground Neutrino Experiment, or DUNE, a collaboration between the U.S. and CERN. In it, neutrinos will be beamed 800 miles from Fermilab in Illinois to a giant underground detector at the Sanford Underground Research Facility, located in an old gold mine in Lead, S.D., to study how the neutrinos oscillate.
“The T2K/SuperK result does not remove the need for the future experiments,” Dr. Wilkinson of CERN said. “Rather, it encourages us that we are on the right track and to look forward to the conclusive results that we expect to get from these new projects.”
He added, “What the Nature paper tells us is that existing experiments have more sensitivity than was previously thought.”
Dr. Lykken, the deputy director of Fermilab, said, “Now we have a good hint that the DUNE experiment will be able to make a definitive discovery of CP violation relatively soon after it turns on later in this decade.”
https://www.nytimes.com/2020/04/15/science/physics-neutrino-antimatter-ichikawa-t2k.html
The scientists running the T2K experiment alternate between sending muon neutrinos and muon antineutrinos — measuring them as they depart Tokai and then measuring them again on arrival in Kamioka, to see how many have changed into regular old electron neutrinos. If nature and neutrinos are playing by the same old-fashioned symmetrical rules, the same amount of change should appear in both beams.
On Wednesday, in the abstract to a rather statistically dense paper, the authors concluded: “Our results indicate CP violation in leptons and our method enables sensitive searches for matter-antimatter asymmetry in neutrino oscillations using accelerator-produced neutrino beams.”
Asked to summarize the result, Dr. Sánchez, a team spokesman, said, “In relative terms more neutrino muons going to neutrino electrons than antineutrino muons going to antineutrino electrons.”
In other words, matter was winning.
This was a step in the right direction but, Dr. Sánchez cautioned, not enough to guarantee victory in the struggle to understand our existence. The big thing, he said, is that the experiment has definitely shown that the neutrinos violate the CP symmetry. Whether they violate it enough is not yet known.
“For a long time theorists have been discussing if CP violation in neutrinos would be enough,” Dr. Sánchez said. “The general agreement now is that it does not seem to be sufficient. But this is just modeling, and we might be wrong.”
More and larger experiments are in the works. Among them is the Deep Underground Neutrino Experiment, or DUNE, a collaboration between the U.S. and CERN. In it, neutrinos will be beamed 800 miles from Fermilab in Illinois to a giant underground detector at the Sanford Underground Research Facility, located in an old gold mine in Lead, S.D., to study how the neutrinos oscillate.
“The T2K/SuperK result does not remove the need for the future experiments,” Dr. Wilkinson of CERN said. “Rather, it encourages us that we are on the right track and to look forward to the conclusive results that we expect to get from these new projects.”
He added, “What the Nature paper tells us is that existing experiments have more sensitivity than was previously thought.”
Dr. Lykken, the deputy director of Fermilab, said, “Now we have a good hint that the DUNE experiment will be able to make a definitive discovery of CP violation relatively soon after it turns on later in this decade.”
https://www.nytimes.com/2020/04/15/science/physics-neutrino-antimatter-ichikawa-t2k.html
