Surprising insights sometimes come in small packages. And sometimes these small packages have to be delivered by very large systems. MIT physicists made some surprising discoveries with a very small radioactive molecule that was produced in an accelerator at CERN. They believe that if these new types of radioactive molecules are studied carefully enough, they could shed some light on why there is more matter than antimatter in the universe.
Radioactive molecules may be a strange place to look for the answer to one of the fundamental questions that has overwhelmed modern physics. However, these are not your everyday radioactive molecules – they usually only exist in neutron star mergers or supernovae. In fact, this is the first time they are made synthetically.
Video discussing the problem of antimatter / matter asymmetry that the new radioactive molecules could solve.
Credit – SciShow YouTube Channel
What makes them interesting is their neutron count. Neutrons usually don’t have much of an impact on a molecule because they are a millionth the size of the molecule they belong to. But the physicists were able to measure the influence of the neutron on the energy of its molecule. That’s a breakthrough in itself, but it wasn’t an easy road to get there.
First, the researchers around MIT’s assistant professor Ronald Fernando Garcia Ruiz had to produce the novel molecule. They were particularly interested in radium monofluoride (RaF), an unstable radioactive molecule that only exists a few seconds after its formation. After successfully making some for the first time last year, they turned to different isotopes of this unstable molecule.
Artist’s impression of a radium monofluoride molecule.
Credit – Garcia Ruiz et al.
The isotopes in question contained different numbers of neutrons. To create these different isotopes, the researchers developed a disk made from uranium carbide and injected carbon-fluoride gas. After tapping it at CERN with a low-energy proton beam, the researchers released a veritable zoo of new molecules, including 5 different isotopes of RaF.
To capture these short-lived isotopes, the researchers used a series of ion traps, lasers, and electromagnetic fields to isolate them. They then measured the mass of each of the 5 molecules to estimate how many neutrons it contained. Another laser explosion then measured the quantum state of each molecule.
Video describing the particle accelerators at work at CERN.
Credit – Science Channel YouTube
Surprisingly, a single neutron difference can have a measurable impact on the overall quantum energy state of the molecule in which it resides. This finding is important as a proof of concept, as it leads to even more dramatic findings for dealing with the symmetry problem.
So how does symmetry fit into this whole exercise in creating these new radioactive molecules? Radium itself is a minor outlier on the symmetry scale, with an atomic nucleus shaped more like a pear than the more symmetrical sphere found in most other atoms. Using this imbalanced core as the basis for the RaF molecule appears to make the molecule itself more susceptible to changes in energy states that would otherwise be imperceptible, such as the presence (or absence) of a neutron.
Discussion of the measurement of quantum variables in the classical world.
Credit – PBS Spacetime YouTube Channel
RaF could therefore possibly be used as a detection mechanism for the infinitesimal forces that would indicate symmetry breaking physics. Demonstrating its susceptibility to the influence of a neutron is only the first step to a much finer analysis required to study symmetry. However, if the almost imperceptible effects that would indicate symmetry breaking forces are present, the RaF molecule or similar molecules are probably our best chance of spotting them.
What kind of a discovery would that be – issues from antimatter / matter imbalance to dark energy could be influenced by such a discovery. But there is still much to be done before possible surprising findings – including increasing the measurement sensitivity of the energy difference by several orders of magnitude. Maybe a bigger particle accelerator can do the trick?
Learn more –
MIT – New clues as to why there is so little antimatter in the universe
MIT physicists measure a short-lived radioactive molecule for the first time
CERN – Isotope Shifts of Radium Monofluoride Molecules
Mission statement –
Stock image that represents an atomic structure.
Credit – MIT News