#axions

And there definitely are atheists and agnostics who have less hard-line "well, maybe..." beliefs or believe in non-deity supernatural stuff like ghosts so ok for checking

But so many people seem to think you must have some residual belief that you're either concealing or repressing. Oh well yeah you don't believe in god but there's things we can't explain right? It's so arrogant to think we know everything. Don't you ever wonder?

Is It Dark Matter? Mystery Signal Goes 'Bump' In World's Most Sensitive Detector

“It's a remarkable feat that the XENON collaboration has achieved by collecting so much high-quality data in such a pristine environment, a triumph for experimental physics regardless of the results. It's a happy surprise, however, that something is definitively causing an excess of events in a very specific low-energy range (from 1-to-7 keV) in the detector itself.

It might just be tritium in the water; a few thousand tritium atoms in the entire apparatus could be the culprit. It could be that the neutrino has a large magnetic moment, but other observations conflict with that interpretation. Or, it could be axions — a specific dark matter candidate particle — produced by the Sun that are confounding the detector.

Either way, there's a new mystery afoot. Something just went "bump" in the world's most sensitive detector experiment, and it might be our first direct clue as to the nature of the Universe's most elusive source of mass: dark matter.”

The XENON experiment was designed to look for dark matter directly, by measuring nuclear recoils off of the xenon atoms in the experiment. While most of the focus has been on heavy, WIMP-like dark matter, XENON has surprised us all by finding an excess signal at extremely low energies: thousands of electron-volts instead of the expected billions.

Watch a CERN telescope follow the sun in timelapse view from inside a building as it attempts to search for axions, one proposed candidate for a constituent of Dark Matter. Here's a summary from their video caption: "Timelapse video of the CERN Axion Solar Telescope (CAST) following the Sun in the morning and in the evening. CAST is an experiment to search for hypothetical particles called "axions". These have been proposed by some theoretical physicists to explain why there is a subtle difference between matter and antimatter in processes involving the weak force, but not the strong force. If axions exist, they could be found in the centre of the Sun and they could also make up invisible dark matter.

Axion particle spotted in solid-state crystal

Scientists at the Max Planck Institute for Chemical Physics of Solids in Dresden, Princeton University, the University of Illinois at Urbana-Champaign, and the University of the Chinese Academy of Sciences have spotted a famously elusive particle: The axion, first predicted 42 years ago as an elementary particle in extensions of the standard model of particle physics. The results of the experiments are published in Nature.

The team found signatures of axion particles composed of Weyl-type electrons (Weyl fermions) in the correlated Weyl semimetal (TaSe4)2I. At room temperature, (TaSe4)2I is a one-dimensional crystal in which electrical current is conducted by Weyl fermions. However, by cooling (TaSe4)2I down below -11 degrees C, these Weyl fermions themselves condense into a crystal, a so-called "charge density wave," which distorts the underlying crystal lattice of the atoms. The initially free Weyl fermions are now localized and the initial Weyl semimetal (TaSe4)2I becomes an axion insulator. Similar to the existence of free electrons in metallic atomic crystals, the Weyl semimetal-based charge-density-wave crystal hosts axions that can conduct electrical current. However, such axions behave quite differently from electrons. When exposed to parallel electric and magnetic fields, they produce an anomalous positive contribution to the magnetoelectric conductivity.

Based on predictions from Andrei Bernevig's group at Princeton University, the group of Claudia Felser in Dresden produced the charge density wave Weyl metalloid (TaSe4)2I and investigated the electrical conduction in this material under the influence of electric and magnetic fields. The researchers found that the electric current in this material below -11 degrees C is actually carried by axion particles. "It's very surprising that materials that we think we know are suddenly showing such interesting quantum particles," says Claudia Felser, one of the lead authors of the paper.

An elusive hypothetical particle comes in imitation form.

Lurking within a solid crystal is a phenomenon that is mathematically similar to proposed subatomic particles called axions, physicist Johannes Gooth and colleagues report online October 7 in Nature.

If axions exist as fundamental particles, they could constitute a hidden form of matter in the cosmos, dark matter. Scientists know dark matter exists thanks to its gravitational pull, but they have yet to identify what it is. Axions are one possibility, but no one has found the particles yet (SN: 4/9/18).

Enter the imitators. The axions analogs within the crystal are a type of quasiparticle, a disturbance in a material that can mimic fundamental particles like axions. Quasiparticles result from the coordinated jostling of electrons within a solid material. It’s a bit like how birds in a flock seem to take on new forms by syncing up their movements.

Axions were first proposed in the context of quantum chromodynamics — the theory that explains the behaviors of quarks, tiny particles that are contained, for example, inside protons. Axions and their new doppelgängers “are mathematically similar but physically totally unrelated,” says theoretical physicist Helen Quinn of SLAC National Accelerator Laboratory in Menlo Park, Calif., one of the scientists who formulated the theory behind axions. That means scientists are no closer to solving their dark matter woes.

Still, the new study reveals for the first time that the phenomenon has a life beyond mere equations, in quasiparticle form. “It’s actually amazing,” says Gooth, of the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany. The idea of axions is “a very mathematical concept, in a sense, but it still exists in reality.”

In the new study, the researchers started with a material that hosts a type of quasiparticle known as a Weyl fermion, which behaves as if massless (SN: 7/16/15). When the material is cooled, Weyl fermions become locked into place, forming a crystal. That results in the density of electrons varying in a regular pattern across the material, like a stationary wave of electric charge, with peaks in the wave corresponding to more electrons and dips corresponding to fewer electrons.

Applying parallel electric and magnetic fields to the crystal caused the wave to slosh back and forth. That sloshing is the mathematical equivalent of an axion, the researchers say.

To confirm that the sloshing was occurring, the team measured the electric current through the crystal. That current grew quickly as the researchers ramped up the electric field’s strength, in a way that is a fingerprint of axion quasiparticles.

Unveiling the Secrets of Dark Matter Vortices The enigmatic nature of dark matter continues to challenge our understanding of the cosmos. While comprising approximately 85% of the universe’s mass, its composition remains one of the most significant mysteries in modern physics. Current theoretical models propose various candidates, from WIMPs (Weakly Interacting Massive Particles) to primordial…