Researchers have discovered a new particle, which is a magnetic relative of the Higgs boson. The discovery of the Higgs boson requires the huge particle acceleration capability of the Large Hadron Collider (LHC), and this kind of never seen particle - known as the axial Higgs boson - was discovered through an experiment that can be placed on a table.
The magnetic cousin of the Higgs boson, the particle responsible for giving other particles mass, may also be a candidate for dark matter. Dark matter accounts for 85% of the total mass of the universe, but it has never appeared and only implies its existence through gravity.
"When my student showed me these data, I thought she must have been wrong," Kenneth birch, a professor of physics at Boston College and lead researcher of the team that made the discovery, told LiveScience. "You don't find a new particle every day that you can find sitting on the table."
The axial Higgs boson is different from the Higgs boson. The latter was first detected by LHC's Atlas and CMS detectors in 2012 ten years ago because it has a magnetic moment, a magnetic force or direction that generates a magnetic field. Therefore, it needs a more complex theory to describe it, rather than the "relatives" of its non-magnetic mass.
In the standard model of particle physics, particles appear from different fields penetrating into the universe, and some of them shape the basic forces of the universe. For example, photon mediated electromagnetism, the large particles called W and Z bosons mediate weak nuclear forces, which dominate nuclear decay at the subatomic level. However, when the universe was young and hot, electromagnetism and weak forces could be regarded as the same thing, because all these particles were almost the same. With the cooling of the universe, weak electricity splits, resulting in the mass of W and Z bosons, which is very different from the behavior of photons. Physicists call this process "symmetry destruction". But how on earth did these particles with weak force become so heavy?
It turns out that these particles interact with a single field, called the Higgs field. The disturbance of this field produces the Higgs boson, and makes the W and Z bosons gain weight.
"The Higgs boson is produced in nature, as long as this symmetry is broken." "However, usually only one symmetry is broken at a time, so Higgs is described only by his energy," Birch said
The theory behind the axial Higgs boson is more complex.
"In the case of axial Higgs boson, it seems that multiple symmetries have been broken together, leading to a new form of theory and Higgs mode (specific oscillation of quantum fields such as Higgs field), which requires multiple parameters to describe it: specifically, energy and magnetic momentum," Birch said.
Birch and his colleagues described the new magnetic "Higgs cousin" in a study published in the journal Nature on Wednesday (June 8). He explained that the original Higgs boson was not directly coupled with light, which means that it must be created by smashing other particles with huge magnets and high-power lasers, and cooling the sample to an extremely low temperature. It was in the process of these primitive particles decaying into other particles that the Higgs particle suddenly appeared, thus revealing its existence.
On the other hand, when the room temperature quantum material simulates a specific set of oscillations, called the axial Higgs mode, the axial Higgs boson is generated. The researchers then used light scattering to observe the particle.
"We discovered the axial Higgs boson using a tabletop optical experiment on a table about 1 x 1 meter by focusing on a material with a unique combination of properties," Birch continued. "Specifically, we used a rare earth telluride (rte3), a quantum material with a highly 2D crystal structure. The electrons in rte3 self organize into a wave in which the density of the charge increases or decreases periodically.".
The magnitude of these charge density waves above room temperature can be modulated over time to produce axial Higgs mode.
In the new study, the team created the axial Higgs mode by sending a color laser to the rte3 crystal. In a process called Raman scattering, light is scattered and becomes a low-frequency color, and the energy lost in the process of color change produces the axial Higgs mode. The team then rotated the crystal and found that the axial Higgs mode also controls the angular momentum of electrons, or their circular velocity in the material, which means that this mode must also be magnetic.
"At first we were just studying the light scattering properties of this material. When we carefully examined the symmetry of the reaction -- how it was different when we rotated the sample -- we found abnormal changes, which was the first hint of something new," Birch explained. "Therefore, it is the first such magnetic Higgs to be discovered, and it shows that the collective behavior of electrons in rte3 is different from any state previously seen in nature."
Particle physicists have previously predicted an axial Higgs model and even used it to explain dark matter, but this is the first time they have observed it. This is also the first time that scientists have observed a state with multiple broken symmetries.
Symmetry breaking occurs when a symmetric system that looks the same in all directions becomes asymmetric. The University of Oregon suggests treating it like a spinning coin. It has two possible states. The coin eventually falls on its front and back, releasing energy and becoming asymmetrical.
This destruction of double symmetry is still consistent with current physical theories, which is exciting because it may be a way to create hitherto unknown particles that can be used to explain dark matter.
"The basic idea is that in order to explain dark matter, you need a theory that is consistent with existing particle experiments, but produces new particles that have not yet been seen. Adding this additional symmetry destruction through the axial Higgs mode is a way to achieve this goal," Birch said Birch said that although physicists had predicted, the observation of the axial Higgs boson was a surprise for the team, who spent a year trying to verify their results.