Neutrinos, though nearly invisible, are among the most numerous matter particles in the universe. The Standard Model recognizes three types, but the discovery of neutrino oscillations revealed they have mass and can change identity while propagating.
For decades, puzzling experimental anomalies have suggested the presence of a fourth, “sterile” neutrino, one that interacts even more weakly. Finding it would transform our understanding of particle physics.
SUNY Poly Professor of Physics Dr. Amir Fariborz recently published a paper in Physical Review D titled “Spinless glueballs in generalized linear sigma model.” The work takes on a central challenge in modern physics: understanding how the strongest force in nature shapes the inner structure of matter, and how it may produce an unusual form of matter made entirely from the carriers of that force.
Here’s the quick background. Everything is made of atoms. Atoms have a nucleus made of protons and neutrons, and those are made of even smaller pieces called quarks. Quarks are held together by gluons, which carry the strong interaction described by quantum chromodynamics (QCD).
Composite subatomic particles—hadrons—are built from quarks and gluons. Hadrons fall into two main groups: mesons and baryons. QCD does a great job explaining what happens when particles collide at very high energies, but at lower energies it becomes much harder to calculate, so researchers use well-tested models that still follow QCD’s rules.
Measurements of the decay of the Higgs boson into muon–antimuon pairs provide evidence for the mechanism by which quarks and leptons acquire their mass.
The most basic bits of matter that we have found are quarks and leptons, which we idealize as point-like objects with no internal structure and no measurable size (experiments constrain their sizes to below an attometer, a billionth of a billionth of a meter). The quarks, which experience strong, weak, and electromagnetic interactions, come in six flavors: up and down (the constituents of the proton and neutron), charm and strange, and top and bottom. The charged leptons—electron, muon, and tau—experience weak and electromagnetic interactions, while the neutral leptons—the three neutrinos—feel only the weak interactions. The masses of the quarks and charged leptons span more than 5 orders of magnitude: The top-quark mass is nearly 340,000 times that of the electron.
It is something like the “Holy Grail” of physics: unifying particle physics and gravitation. The world of tiny particles is described extremely well by quantum theory, while the world of gravitation is captured by Einstein’s general theory of relativity. But combining the two has not yet worked—the two leading theories of theoretical physics still do not quite fit together.
There are many ideas for such a unification—with names like string theory, loop quantum gravity, canonical quantum gravity or asymptotically safe gravity. Each of them has its strengths and weaknesses. What has been missing so far, however, are observable predictions for measurable quantities and experimental data that could reveal which of these theories actually describes nature best. A new study from TU Wien published in Physical Review D may now have brought us a small step closer to this ambitious goal.
XLight, a U.S.-based startup developing an EUV light source based on a particle accelerator, on Tuesday signed a Letter of Intent (LOI) with the U.S. Department of Commerce for $150 million in proposed federal incentives under the CHIPS and Science Act. xLight came out of the blue earlier this year when it hired Pat Gelsinger, former chief executive of Intel, as executive chairman. The money, if awarded, will be used to bring xLight’s free-electron laser (FEL) based light source closer to reality once it is built in Albany and its viability is proven in practice.
“With the support from the [Department of] Commerce, our investors, and development partners, xLight is building its first free-electron laser system at the Albany Nanotech Complex, where the world’s best lithography capabilities will enable the research and development that will define the future of chip manufacturing,” said Nicholas Kelez, CEO and CTO of xLight.
An exploration of the mystery of the impossible neutrino detection and how that might be our first direct detection of dark matter.
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Umbrella toxin particles produced by Actinobacteria contain five spokes tipped with variable lectin domains. Here, Zhao et al. show that these lectins mediate species-specific binding to a previously unrecognized cell surface carbohydrate polymer and propose that the modular nature of umbrella particles enables bet hedging against unpredictable competitor encounters.
A new type of sensor that levitates dozens of glass microparticles could revolutionize the accuracy and efficiency of sensing, laying the foundation for better autonomous vehicles, navigation and even the detection of dark matter.
Using a camera inspired by the human eye, scientists from King’s College London believe they could track upwards of 100 floating particles in what could be one of the most sensitive sensors to date.
Levitating sensors typically isolate small particles to observe and quantify the impact of outside forces like acceleration on them. The higher the number of particles which could be disturbed and the greater their isolation from their environment, the more accurate the sensor can be.
Using sound to get objects to float works well if a single particle is levitated, but it causes multiple particles to collapse into a clump in mid-air. Physicists at the Institute of Science and Technology Austria (ISTA) have now found a way to keep them apart using charge. Their findings, published in Proceedings of the National Academy of Sciences, could find applications in materials science, robotics, and microengineering.
Who hasn’t dreamed of overcoming gravity and getting objects to hover above ground?
In 2013, Scott Waitukaitis, now an assistant professor at the Institute of Science and Technology Austria (ISTA), became interested in using acoustic levitation as a tool to study various physical phenomena. At that time, only a handful of research groups were using this technique for similar purposes.
And this isn’t the only close match. The energy signature of these gamma-rays closely matches those predicted to emerge from the annihilation of colliding WIMPs, which are predicted to have a mass around 500 times that of a proton, the ordinary matter particles found at the heart of atoms. Totani suggests there aren’t any other astronomical phenomena that easily explain the gamma-rays observed by Fermi.
“If this is correct, to the extent of my knowledge, it would mark the first time humanity has ‘seen’ dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics,” Totani said. “This signifies a major development in astronomy and physics.”
While Totani is confident that what he and his colleagues have detected is the signature of dark matter WIMPs annihilating each other at the heart of the Milky Way, the scientific community in general will require more hard evidence before the book is closed on this nearly century-old mystery.