Researchers have identified a magnetic cousin of the Higgs boson. Whereas the Higgs boson was discovered utilizing the massive particle-accelerating power of the Large Hadron Collider (LHC), the axial Higgs boson was found using an experiment that could fit on a tiny kitchen tabletop.
This magnetic cousin of the Higgs boson — the particle responsible for giving other particles their mass — might be a candidate for dark matter, which accounts for 85 percent of the total group of the universe but is only revealed via gravity.
“When my student presented me the results, I believed she had to be incorrect,” Kenneth Burch, a physics professor at Boston College and the team’s principal researcher, told Live Science. “It’s not every day that you come upon a new particle on your tabletop.”Â
The axial Higgs boson differs from the Higgs boson, discovered a decade ago in 2012 by the ATLAS and CMS detectors at the LHC, in that it possesses a magnetic moment, magnetic strength, or orientation that generates a magnetic field. As a result, it necessitates a more sophisticated theory than its non-magnetic mass-granting relative.
Particles come from many fields that permeate the world under the Standard Model of particle physics, and some of these particles form the universe’s fundamental forces. Photons, for example, mediate electromagnetism, whereas heavy particles known as W and Z bosons mediate the weak nuclear force, which drives nuclear disintegration at the subatomic level.
However, when the cosmos was young and hot, electromagnetism and the weak force were the same, and all of these particles were almost identical. The electroweak power split when the cosmos cooled, leading the W and Z bosons to develop mass and act significantly differently from photons, a phenomenon physicists term “symmetry breaking.” But how did these weak-force-mediating particles get so massive?
These particles, it turns out, interacted with a distinct field known as the Higgs field. Perturbations in that field gave birth to the Higgs boson and imparted weight to the W and Z bosons.
When such symmetry is violated in Nature, the Higgs boson is created. “However, since only one symmetry is violated at a time, the Higgs is simply characterized by its energy,” Burch said.
The axial Higgs boson hypothesis is more complicated.
“It appears that multiple symmetries are broken together in the case of the axial Higgs boson, leading to a new form of the theory and a Higgs mode [the specific oscillations of a quantum field like the Higgs field] that requires multiple parameters to describe it: specifically, energy and magnetic momentum,” Burch said.
Burch, who described the new magnetic Higgs cousin with colleagues in a study published Wednesday (June 8) in the journal Nature, explained that the original Higgs boson does not couple directly with light, so it must be created by smashing other particles together with giant magnets and high-powered lasers while also cooling samples to frigid temperatures. The disintegration of those initial particles shows the presence of the Higgs in others that appear briefly.
On the other hand, the axial Higgs boson appeared when quantum materials at ambient temperature emulated a particular set of oscillations known as the axial Higgs mode. The particle was then seen via light scattering by the researchers.
“We discovered the axial Higgs boson by concentrating on a material with a particular mix of features,” Burch said. “We employed rare-earth Tritelluride (RTe3) [a quantum material with a highly 2D crystal structure] in particular. The electrons in RTe3 self-organize into a wave where the charge density is repeatedly increased or decreased.”
The axial Higgs mode is produced by modulating the magnitude of these charge density waves that appear above room temperature.
The axial Higgs model was established in the latest research by putting one-color laser light into the RTe3 crystal. Raman scattering occurs when light scatters and changes to a lower frequency color, and the energy lost during the color shift creates the axial Higgs mode. The scientists next rotated the crystal and discovered that the axial Higgs mode governs the angular momentum of the electrons in the material or the pace at which they travel in a circle, implying that this mode is also magnetic.
“Initially, we were interested in the material’s light scattering capabilities. We observed abnormal variations that were the first clues of anything unusual when we carefully examined the symmetry of the response — how it altered as we rotated the sample,” Burch elaborated. “As so, it is the first magnetic Higgs to be identified, indicating that the collective behavior of the electrons in RTe3 is unlike any condition ever seen in nature.”
Particle scientists had previously anticipated an axial Higgs mode and even used it to explain dark matter, but this is the first time it has been seen. Scientists have also seen a condition with multiple broken symmetries for the first time.
When a symmetric system that seems the same in all directions turns asymmetric, this is referred to as symmetry breakdown. Oregon University proposes seeing this as a spinning coin with two probable outcomes. The coin finally falls upon its face, either the head or tail, releasing energy and becoming asymmetrical.
This breach of double symmetry still fits with existing physics theories and is fascinating because it might be a method of producing previously undiscovered particles that could explain dark matter.
“The fundamental concept is that to explain dark matter, you need a hypothesis compatible with known particle investigations while also creating new particles that have not yet been seen,” Burch said.
He says that adding this additional symmetry-breaking through the axial Higgs wave is one method. Despite being expected by physicists, the team was shocked by the discovery of the axial Higgs boson. They spent a year seeking to validate their findings, according to Burch.
