We are all here only because reality is an imperfect reflection of itself. Due to the lack of symmetry in the universe, a lot of matter is available to coalesce into the billions of galaxies that we see today.
For nearly a decade, scientists have been collecting data from the Tokai to Kamioka (T2K) particle physics experiment in Japan. They are the most compelling evidence of imbalance, which may help explain why matter did not disappear the moment it emerged.
The study looked for significant differences in how nearly massless particles called neutrinos change shape compared to their 'mirror' particle, antineutrinos.
Ironically, neutrinos are so tiny they hardly exist, they slide past most other particles without interacting. But what they lack, they make up in huge quantities, occurring a billion times more often than particles that settle together to form atoms.
In fact, this abundance of neutrinos, mixed with their strange behavior and changing properties, attracts physicists looking for an explanation for everything from dark matter to the apparent imbalance in the types of particles we see around us.
Long ago, when the universe was still a hot disorder packed into tiny (but expanding) space, the condensation of energy in particles should have produced pairs of particles with opposite properties.
This means that negatively charged electrons appeared next to positively charged antimatter twins called positrons. Since matter in combination with antimatter disappears in the beam of radiation, space must be filled with nothing more essential than waves of light.
This is obviously not the case. At least not really. Enough particles of matter stuck together around them to eventually create things like stars, comets, bombs, and paper clips.
“Equal amounts of matter and antimatter were created in the early universe, so an important question in cosmology is how we got to the universe we see today, where matter is dominant,” said experimental physicist Lindsay Bignell of ANU in Australia.
“We don't have a complete picture of how this happened yet, but we do know that symmetry breaking is a necessary component,” says Bignell.
Symmetry means the exchange of charge and parity, particle changes that occur in opposition. For example, positive charges become negative when particles become antiparticles. As far as parity is concerned, this is a coordinate shift, not unlike the fact that your left hand is a mirror image of your right.
The mass of data in this study means we can be more confident than ever that breaking this critical symmetry is what lies behind the observed pattern in oscillating neutrinos.
We are still far from a definitive answer to the question of why matter exists as it exists, and we will have to wait for future experiments to determine if this particular violation will help explain this. If not, then we may have to wait for completely new physics.
This study was published in the journal Nature.
Sources: Photo: Super Kamiokand Neutrino Detector. (Kamioka Observatory / ICRR / University of Tokyo)
