Observing a phenomenon known as ‘neutrino oscillations’, science seeks an answer to why we live in a universe of matter and not antimatter, its identical replica.
The scientists José Bernabéu and Alejandro Segarra of the Institute of Corpuscular Physics (IFIC, mixed center of the University of Valencia and the CSIC) (Spain) have just published in the Physical Review Letters the solution to a problem that had been discussed in physics neutrinos for decades.
Observing a phenomenon known as ‘neutrino oscillations’, science seeks an answer to why we live in a universe of matter and not antimatter, its identical replica. However, this process is affected by the Earth itself, made of matter, which creates a deceptive effect that was considered inseparable from the genuine observation of the differences between matter and antimatter.
Now the two researchers propose a way to ‘unravel’ or separate both effects, with application in future experiments such as DUNE in the United States and T2HK in Japan.
Neutrinos are special elementary particles: they have almost no mass and rarely interact with the rest of known matter. They abound in a still undetected radiation produced in the primitive time of the universe, and are believed to hold the key to material-antimatter asymmetry, the explanation of why matter was imposed on antimatter to form everything we see in the cosmos.
To study this question, one of the most important in Physics, we compare the behavior of neutrinos and their antimatter replica, the antineutrinos, produced in particle accelerators and detected hundreds of kilometers from their origin.During that trip the neutrinos ‘oscillate’, they are transformed between the three types that are known (electronic, muónico and tauónico). This phenomenon, known as ‘oscillations of neutrinos’ and whose discovery was the Nobel Prize for Physics in 2015, occurs inside the Earth, since neutrinos can cross it by interacting very little with the material that forms it. The two authors present a theorem of unraveling the two effects, which have different properties under other fundamental symmetries of physics such as the so-called temporary investment (T) and the combined load, parity and temporary investment (CPT), studied previously by Bernabéu in other physical systems.
José Bernabéu y Alejandro Segarra. 2018. Disentangling Genuine from Matter-Induced CP Violation in Neutrino Oscillations. Phys. Rev. Lett. DOI: 10.1103/PhysRevLett.121.211802