Neutrinos are so tiny and inconspicuous that physicists believed for a long time they had no mass. Now, a massive device that scientists say will determine the mass of neutrinos has begun operation in Karlsruhe.
What is the exact mass of the three known kinds of neutrinos? Any answers? No? Well, don’t worry, because nobody knows. Not yet. Electron, muon and tau neutrinos are simply too difficult to grasp for scientists.
What would it say about the fundamental structure of the universe?
Physicists working at the Large Hadron Collider have made a major new detection of the famous Higgs boson, this time catching details on a rare interaction with one of the heaviest fundamental particles known to physics — the top quark.
The brief mingling of these incredibly rare encounters has provided physicists with important information on the nature of mass, and whether there is more to physics than the existing model predicts.
Results produced by the ATLAS and CMS experiments from the European Organization for Nuclear Research (CERN) help confirm the strength of the bond between Higgs bosons and top quarks.
The Higgs boson appeared again at the world’s largest atom smasher — this time, alongside a top quark and an antitop quark, the heaviest known fundamental particles. And this new discovery could help scientists better understand why fundamental particles have the mass they do.
When scientists at the Large Hadron Collider (LHC) first confirmed the Higgs’ existence back in 2013, it was a big deal. As Live Science reported at the time, the discovery filled in the last missing piece of the Standard Model of physics, which explains the behavior of tiny subatomic particles. It also confirmed physicists’ basic assumptions about how the universe works. But simply finding the Higgs didn’t answer every question scientists have about how the Higgs behaves. This new observation starts to fill in the gaps.
As the European Organization for Nuclear Research (CERN), the scientific organization that operates the LHC, explained in a statement, one of the most significant mysteries in particle physics is the major mass differences between fermions, the particles that make up matter. An electron, for example, is a bit less than one three-millionth the mass of a top quark. Researchers believe that the Higgs boson, with its role (as Live Science previously explained) in giving rise to mass in the universe, could be the key to that mystery. [Top 5 Implications of Finding the Higgs Boson ].
Scientists have produced the firmest evidence yet of so-called sterile neutrinos, mysterious particles that pass through matter without interacting with it at all.
The first hints these elusive particles turned up decades ago. But after years of dedicated searches, scientists have been unable to find any other evidence for them, with many experiments contradicting those old results. These new results now leave scientists with two robust experiments that seem to demonstrate the existence of sterile neutrinos, even as other experiments continue to suggest sterile neutrinos don’t exist at all.
That means there’s something strange happening in the universe that is making humanity’s most cutting-edge physics experiments contradict one another. [The 18 Biggest Unsolved Mysteries in Physics].
A rare earth element that doesn’t get much mention could become the key to upgrading atomic clocks to become even more accurate. This could help us explore space and track satellites, and even keep the world’s time zones in sync.
Atomic clocks use the oscillations of atoms under laser fire as a measurement of time, in the same way a grandfather clock uses the swing of a pendulum. They can lose less than a second over 50 million years, depending on the elements used — but scientists want even greater accuracy.
That’s where lutetium (Lu) comes in. It offers both a higher level of stability and a higher degree of precision than the caesium or rubidium of today’s atomic clocks, according to a team of researchers from the Centre for Quantum Technologies (CQT) in Singapore.
In general, modelers attack the problem by breaking it into billions of bits, either by dividing space into a 3D grid of subvolumes or by parceling the mass of dark and ordinary matter into swarms of particles. The simulation then tracks the interactions among those elements while ticking through cosmic time in, say, million-year steps. The computations strain even the most powerful supercomputers. BlueTides, for example, runs on Blue Waters—a supercomputer at the University of Illinois in Urbana that can perform 13 quadrillion calculations per second. Merely loading the model consumes 90% of the computer’s available memory, Feng says.
For years such simulations produced galaxies that were too gassy, massive, and blobby. But computer power has increased, and, more important, models of the radiation-matter feedback have improved. Now, hydrodynamic simulations have begun to produce the right number of galaxies of the right masses and shapes—spiral disks, squat ellipticals, spherical dwarfs, and oddball irregulars—says Volker Springel, a cosmologist at the Heidelberg Institute for Theoretical Studies in Germany who worked on Millennium and leads the Illustris simulation. “Until recently, the simulation field struggled to make spiral galaxies,” he says. “It’s only in the last 5 years that we’ve shown that you can make them.”
The models now show that, like people, galaxies tend to go through distinct life stages, Hopkins says. When young, a galaxy roils with activity, as one merger after another stretches and contorts it, inducing spurts of star formation. After a few billion years, the galaxy tends to settle into a relatively placid and stable middle age. Later, it can even slip into senescence as it loses its gas and the ability make stars—a transition our Milky Way appears to be making now, Hopkins says. But the wild and violent turns of adolescence make the particular path of any galaxy hard to predict, he says.
Inside the proton, there is an immense amount of pressure which is equivalent to a billion, billion times the pressure at the bottom of the Mariana Trench. Scientists at the Thomas Jefferson National Accelerator Facility have measured the pressure inside the proton for the first time. To probe the conditions within the proton, Burkert and his colleagues used an electron beam to probe the inner conditions of a proton. In simple terms, the electrons in the electron beam have energy and this is handed over to one of the quarks. This causes the entire proton to recoil and the quark emits a high-energy photon. By using conservation of momentum and measuring the positions and energies of the photon, proton, and electron in the experiment provides insight into the inner structure of the proton.
It isn’t always easy to wrap your mind around how light works. It’s a particle, but it’s also a wave, and that wave can be powerful. Photons generally travel en masse — we’re talking densities in the range of quadrillions per square inch if they’re coming from the sun. But what if instead of the whole wave crashing over you, you were only hit by a single drop of light — would you know? In other words, is it possible for the human eye to see a single photon?
Based on complex simulations of quantum chromodynamics performed using the K computer, one of the most powerful computers in the world, the HAL QCD Collaboration, made up of scientists from the RIKEN Nishina Center for Accelerator-based Science and the RIKEN Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program, together with colleagues from a number of universities, have predicted a new type of “dibaryon”—a particle that contains six quarks instead of the usual three. Studying how these elements form could help scientists understand the interactions among elementary particles in extreme environments such as the interiors of neutron stars or the early universe moments after the Big Bang.
Particles known as “baryons”—principally protons and neutrons—are composed of three quarks bound tightly together, with their charge depending on the “color” of the quarks that make them up. A dibaryon is essentially a system with two baryons. There is one known dibaryon in nature—deuteron, a deuterium (or heavy-hydrogen) nucleus that contains a proton and a neutron that are very lightly bound. Scientists have long wondered whether there could be other types of dibaryons. Despite searches, no other dibaryon has been found.
The group, in work published in Physical Review Letters, has now used powerful theoretical and computational tools to predict the existence of a “most strange” dibaryon, made up of two “Omega baryons” that contain three strange quarks each. They named it “di-Omega”. The group also suggested a way to look for these strange particles through experiments with heavy ion collisions planned in Europe and Japan.
