#particle-physics

#particle-physics

A core question we want to understand is where did matter come from. And then, if you know about antimatter, it's natural to ask, why is that not here? The process is not understood and we are hunting for clues as to why it happened, says Dr Christian Smorra, a physicist on the Baryon Antibaryon Symmetry Experiment (Base) at Cern.

Whereas we're fully aware of the full suite of Standard Model particles - quarks, charged leptons, neutrinos, their antiparticles, plus the photon, the gluons, the W-and-Z bosons, and the Higgs boson - dark matter must be composed of something else entirely: something novel and not yet directly detected.

In antiquity, many opined about "the elements" in combination. Around 2500 years ago, Leucippus and Democritus founded the idea of atoms. Perhaps everything, they opined, was composed of indivisible building blocks. In the late 1700s, hydrogen and oxygen were discovered. Circa 1804, John Dalton revived atomism to explain chemical behavior. Then in 1869, Mendeleev developed the periodic table: organizing the atoms.

For the past quarter-century, scientists using a particle collider on Long Island have been smashing the nuclei of gold atoms together at nearly the speed of light to create the hottest matter ever made on Earth. The soup of particles born from the collision mimics the universe as it was just after the big bang. Now researchers have at last accurately measured the temperature of this matter for the first time.

Matter and antimatter mirror each other in all respects but electric charge; physicists are excited by small differences in their behaviors. Recently, observations at the world's largest particle collider revealed a new class of antimatter particles breaking down differently than matter counterparts. This discovery contributes to the quest to understand why our universe consists of matter as opposed to an equal balance with antimatter, a situation suggested by early universe theories.

The search for axions remains crucial in the ongoing quest to understand dark matter, though no direct evidence for these particles has yet been found.

The radio waves that we detected were at really steep angles, like 30 degrees below the surface of the ice. They defy the current understanding of particle physics.

Recent precision measurements on antiprotonic systems have advanced our understanding of fundamental symmetries in particle physics and tested the limits of the Standard Model.

Axion quasiparticles are simulations of axion particles, which can be further used as a detector of actual particles. If a dark matter axion hits our material, it excites the quasiparticle, and, by detecting this reaction, we can confirm the presence of the dark matter axion.

The Karlsruhe Tritium Neutrino (KATRIN) experiment has measured the upper limit of the neutrino's mass to 0.45 electron volts, advancing our understanding of this elusive particle.