In new research, a team of scientists calculated an attribute of the neutron more accurately than ever before.
The team from the Paul Scherrer Institute (PSI) found out that neutron has a substantially smaller electric dipole moment (EDM) than they earlier estimated. Their calculations go against the long background of EDM research testing physics violating time-reversal invariance.
The assumption then is that if the neutron has an electric dipole moment (nEDM) with a calculable non-zero value, this could be because of the same physical notion that would also explain the excess of matter after the Big Bang.
The hunt for nEDM can simply be explained as to whether the neutron is an electric compass. It has been obvious for a while now that the neutron is a magnetic compass and reacts to a magnetic field, or simply put, has a magnetic dipole moment. If additionally, the neutron has an electric dipole minute, its worth would be significantly less, as well as more challenging to assess.
Therefore, the researchers at PSI required to put a lot of work into making the local magnetic field stay very consistent throughout their latest research. The number of neutrons analyzed needed to be sufficiently large to offer a possibility to calculate the nEDM. Researchers at PSI had led these measurements over a period of two years, and the so-called ultracold neutrons, which are neutrons with an incredibly slow speed, were also assayed.
Philipp Schmidt-Wellenburg, a scientist on the nEDM project on the part of PSI, said, “Even for PSI with its large research facilities, this was a fairly extensive study. But that is exactly what is needed these days if we are looking for physics beyond the Standard Model.”
Two Teams Determined the Results
The new outcome was decided by a team of researchers at 18 institutes and universities in Europe and the United States, including the ETH Zurich, the University of Bern and the University of Fribourg.
The information has been collected at PSI’s ultracold neutron source, during a period of two years, analyzed it thoroughly in two separate teams, and got a more precise result than ever before.
Schmidt-Wellenburg said: “The research at CERN is broad and generally searches for new particles and their properties. We, on the other hand, are going deep because we are only looking at the properties of one particle, the neutron. In exchange, however, we achieve an accuracy in this detail that the LHC might only reach in 100 years.”
Georg Bison, who is also a researcher in the Laboratory for Particle Physics at PSI, said: “Ultimately, various measurements on the cosmological scale show deviations from the Standard Model. In contrast, no one has yet been able to reproduce these results in the laboratory. This is one of the huge questions in modern physics, and that’s what makes our work so exciting.”
According to Bison, “when we started up the current source for ultracold neutrons here at PSI in 2010, we already knew that the rest of the experiment wouldn’t quite do it justice. So we are currently building an appropriately larger experiment.”
The paper detailing the results has been published in the journal Physical Review Letters.