A team of researchers at MIT has introduced a groundbreaking technique to investigate the inner workings of atomic nuclei. This innovative method leverages the atom”s own electrons as “messengers” within molecules, allowing scientists to gain insights into the nucleus itself.
According to study co-author Ronald Fernando Garcia Ruiz, the Thomas A. Franck Associate Professor of Physics at MIT, “Our results lay the groundwork for subsequent studies aiming to measure violations of fundamental symmetries at the nuclear level. This could provide answers to some of the most pressing questions in modern physics.”
Traditionally, probing the interiors of atomic nuclei requires massive facilities, often spanning kilometers, that accelerate electron beams to extreme speeds for collisions that can disrupt nuclei. However, the newly developed molecule-based method presents a compact, table-top alternative for direct examination of atomic nuclei.
The research team focused on the molecule of radium monofluoride, which combines a radium atom with a fluoride atom. They successfully measured the energy of electrons orbiting around the radium atom, using the molecular environment as a microscopic particle collider that enabled the electrons to briefly interact with the nucleus.
Through their experiments, the researchers observed a minor energy shift indicating that the electrons had interacted with the nucleus of the radium atom. This energy alteration serves as a nuclear “message” that can be analyzed to reveal information regarding the internal structure of the nucleus.
The new technique offers a novel approach to measuring the nuclear “magnetic distribution.” In the nucleus, protons and neutrons act like tiny magnets, and their alignment varies based on the distribution of these particles. The team plans to employ their method to map this characteristic of the radium nucleus for the first time, as outlined in a recent press release.
Understanding this magnetic distribution could shed light on one of the most significant puzzles in cosmology: the apparent excess of matter over antimatter in the universe.
Published in the journal Science, the study details precision laser spectroscopy measurements along with theoretical calculations concerning the structure of the radioactive radium monofluoride molecule, identified as 225Ra19F. The researchers emphasized that the findings reveal intricate details of the short-range interaction between electrons and the nucleus, highlighting the molecule”s sensitivity to the distribution of magnetization, a nuclear property that remains poorly understood.
According to the study, “These results provide a direct and stringent test of the description of the electronic wavefunction inside the nuclear volume, highlighting the suitability of these molecules to investigate subatomic phenomena.” Garcia Ruiz noted that the radium nucleus is expected to amplify symmetry breaking due to its unusual asymmetric charge and mass.
Investigating fundamental symmetries within the nucleus of a radium atom presents significant challenges. “Radium is naturally radioactive, with a short lifespan, and we can currently only produce radium monofluoride molecules in tiny quantities,” explained lead author Shane Wilkins, a former postdoctoral researcher at MIT. “Thus, we require extremely sensitive techniques to conduct measurements.”
