Particle physics experiments

New Higgs-related particle discovered in tabletop experiments

Artist’s impression of the Axial Higgs mode. Image Credit: Nature

The most complex interactions of fundamental particles require extremely powerful accelerators, which would have to be huge to deliver this kind of energy. But sometimes it’s possible to trick mother nature into delivering new fundamental truths with a much more compact tabletop design.

As reported in More on this topic This article is published in NatureNature, a team led by physicists from Boston College has discovered a new quantum excitation, known as the axial Higgs mode. This elusive new particle is a magnetic relative of the mass-defining Higgs boson particle, which was discovered at CERN in 2012.

The discovery was made possible by RTe3, or rare earth tritelluride, a well-studied quantum material that can be examined at room temperature in a “tabletop” experiment. This material is very special because the electrons shared between the compound self-organize with periodic density in space – they create a charge density wave.

And this charge density wave is quite rare because it forms at high temperatures (and not at absolute zero as is often the case in experiments) and is modulated by both charge density and atomic orbits . And the Higgs boson plays a role in both. Using lasers, the team was able to modify the charge density wave and see the response of the Higgs and related components.

“So we were able to reveal the hidden magnetic component and prove the discovery of the first axial Higgs mode,” Professor Kenneth Burch, from Boston College, said in a statement.

By using the right choice of lasers it was possible to test different hypotheses and they did so in a way that allowed them to look at the collective properties of the Higgs bosons in this material and look for possible modes excited. And the one that seems to have been discovered is a version of the Higgs with angular momentum, something the “normal” Higgs boson doesn’t have.

“Axial Higgs detection has been predicted in high-energy particle physics to explain dark matter,” Burch said. “However, this has never been observed. Its appearance in a condensed matter system is quite surprising and announces the discovery of a new state of broken symmetry which had not been predicted. Unlike the extreme conditions generally required to observe new particles, this was done at room temperature in a tabletop experiment where we get quantum control of the mode by simply changing the polarization of light.

This work suggests that charge density waves have the ability to be used as quantum sensors that can assess other quantum systems. But a full understanding of the Higgs and its possible excitation modes could help answer fundamental questions in particle physics such as dark matter and the limits of the Standard Model of particle physics.