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Archive for the ‘particle physics’ category: Page 334

Dec 5, 2020

Researchers observe what could be the first hints of dark bosons

Posted by in categories: cosmology, particle physics

Extremely light and weakly interacting particles may play a crucial role in cosmology and in the ongoing search for dark matter. Unfortunately, however, these particles have so far proved very difficult to detect using existing high-energy colliders. Researchers worldwide have thus been trying to develop alternative technologies and methods that could enable the detection of these particles.

Over the past few years, collaborations between particle and atomic physicists working at different institutes worldwide have led to the development of a new technique that could be used to detect interactions between very light bosons and neutrons or electrons. Light bosons, in fact, should change the energy levels of electrons in atoms and ions, a change that could be detectable using the technique proposed by these teams of researchers.

Using this method, two different research groups (one at Aarhus University in Denmark and the other at Massachusetts Institute of Technology) recently performed experiments aimed at gathering hints of the existence of dark bosons, elusive particles that are among the most promising dark matter candidates or mediators to a dark sector. Their findings, published in Physical Review Letters, could have important implications for future dark matter experiments.

Dec 3, 2020

Magnetism Does the Twist: Skyrmions 10,000 Times Thinner Than a Human Hair Could Advance High-Density Data Storage

Posted by in categories: climatology, computing, particle physics, quantum physics

Scientists discovered a strategy for layering dissimilar crystals with atomic precision to control the size of resulting magnetic quasi-particles called skyrmions. This approach could advance high-density data storage and quantum magnets for quantum information science.

In typical ferromagnets, magnetic spins align up or down. Yet in skyrmions, they twist and swirl, forming unique shapes like petite porcupines or tiny tornadoes.

The tiny intertwined magnetic structures could innovate high-density data storage, for which size does matter and must be small. The Oak Ridge National Laboratory-led project produced skyrmions as small as 10 nanometers – 10,000 times thinner than a human hair.

Dec 3, 2020

Research leads to better modeling of hypersonic flow

Posted by in categories: engineering, military, particle physics

Hypersonic flight is conventionally referred to as the ability to fly at speeds significantly faster than the speed of sound and presents an extraordinary set of technical challenges. As an example, when a space capsule re-enters Earth’s atmosphere, it reaches hypersonic speeds—more than five times the speed of sound—and generates temperatures over 4,000 degrees Fahrenheit on its exterior surface. Designing a thermal protection system to keep astronauts and cargo safe requires an understanding at the molecular level of the complicated physics going on in the gas that flows around the vehicle.

Recent research at the University of Illinois Urbana-Champaign added new knowledge about the physical phenomena that occur as atoms vibrate, rotate, and collide in this extreme environment.

“Due to the relative velocity of the flow surrounding the vehicle, a shock is formed in front of the capsule. When the gas molecules cross the shock, some of their properties change almost instantaneously. Instead, others don’t have enough time to adjust to the abrupt changes, and they don’t reach their equilibrium values before arriving at the surface of the vehicle. The layer between the shock and heat shield is then found in nonequilibrium. There is a lot that we don’t understand yet about the reactions that happen in this type of flow,” said Simone Venturi. He is a graduate student studying with Marco Panesi in the Department of Aerospace Engineering at UIUC.

Dec 2, 2020

Why the Future of Nuclear Power Is Tiny and Factory-Made

Posted by in categories: nuclear energy, particle physics

In the 1950s, few things seemed more futuristic and utopian than harnessing nuclear energy to power your home. Towering nuclear reactors popped up across the U.S. with the promise of harvesting energy from smashed atoms of Uranium to power everything from lights in an office to an oven cooking a pot roast. With clean and efficient nuclear power, anything seemed possible.

But as the years went on, doubt about the safety of these reactors began to poison the bright future they’d once promised. Stories of nuclear waste polluting waterways downstream of power plants began to stir alarm, and in the 1980s the Chernobyl nuclear power plant explosion sent radiation billowing across Europe and into the tissues of an estimated 4,000 Ukrainians who died from radiation poisoning. Even as recently as 2011, Japan’s Fukushima nuclear power plant faced catastrophe when a tsunami knocked out its power supply and led all three of its nuclear reactors to melt down.

All in all, it’s been a tough few decades for nuclear energy’s public image. But nuclear scientists say that now, more than ever, is the time to reinvest in nuclear innovation. Governments agree: In the U.K. Rolls-Royce plans to roll out 16 mini-nuclear plants over the next five years and China, an emerging nuclear super power, has pledged to ramp up its nuclear use to meet emissions goals.

Dec 2, 2020

Heavy boson triplets test Standard Model

Posted by in category: particle physics

A recent observation of an extremely rare subatomic process allows scientists to test the Standard Model’s boundaries.

Dec 1, 2020

In search for dark matter, new fountain design could become wellspring of answers

Posted by in categories: cosmology, particle physics

You can’t see it. You can’t feel it. But the substance scientists refer to as dark matter could account for five times as much “stuff” in the universe as the regular matter that forms everything from trees, trains and the air you breathe, to stars, planets and interstellar dust clouds.

Though scientists see the signature of indirectly in the way large objects orbit one another—particularly how stars swirl around the centers of spiral galaxies—no one knows yet what comprises this substance. One of the candidates is a Z’ boson, a fundamental particle that has been theorized to exist but never detected.

A new proposed experiment could help scientists determine whether Z’ bosons are real, in that way identifying a possible candidate for dark matter. To accomplish this task, researchers from the National Institute of Standards and Technology (NIST), the University of Groningen in the Netherlands, the Canadian particle accelerator center TRIUMF and other collaborators are working to make the most to date of a nuclear property that is extremely difficult to measure, called nuclear spin-dependent parity violation (NSD-PV).

Dec 1, 2020

Astrophysicists Find Hints of Beyond-Standard-Model Physics in Universe’s Oldest Light

Posted by in categories: cosmology, particle physics

Using the polarization data from ESA’s Planck satellite, a mission that have studied the Cosmic Microwave Background (CMB), the oldest light in the Universe, a duo of astrophysicists has uncovered intriguing signs of new physics beyond the Standard Model of elementary particles and fields.

Dec 1, 2020

Next step in simulating the universe

Posted by in categories: computing, particle physics

Computer simulations have struggled to capture the impact of elusive particles called neutrinos on the formation and growth of the large-scale structure of the universe. But now, a research team from Japan has developed a method that overcomes this hurdle.

In a study published this month in the Astrophysical Journal, researchers led by the University of Tsukuba present simulations that accurately depict the role of in the evolution of the universe.

Why are these simulations important? One key reason is that they can set constraints on a currently unknown quantity: the neutrino mass. If this quantity is set to a particular value in the simulations and the differ from observations, that value can be ruled out. However, the constraints can be trusted only if the simulations are accurate, which was not guaranteed in previous work. The team behind this latest research aimed to address this limitation.

Dec 1, 2020

Lower current leads to highly efficient memory

Posted by in categories: computing, particle physics, quantum physics

Researchers are a step closer to realizing a new kind of memory that works according to the principles of spintronics which is analogous to, but different from, electronics. Their unique gallium arsenide-based ferromagnetic semiconductor can act as memory by quickly switching its magnetic state in the presence of an induced current at low power. Previously, such current-induced magnetization switching was unstable and drew a lot of power, but this new material both suppresses the instability and lowers the power consumption too.

The field of quantum computing often gets covered in the technical press; however, another emerging field along similar lines tends to get overlooked, and that is spintronics. In a nutshell, spintronic devices could replace some and offer greater performance at far low power levels. Electronic devices use the motion of electrons for power and communication. Whereas use a transferable property of stationary electrons, their angular momentum, or spin. It’s a bit like having a line of people pass on a message from one to the other rather than have the person at one end run to the other. Spintronics reduces the effort needed to perform computational or memory functions.

Spintronic-based memory devices are likely to become common as they have a useful feature in that they are nonvolatile, meaning that once they are in a certain state, they maintain that state even without power. Conventional computer memory, such as DRAM and SRAM made of ordinary semiconductors, loses its state when it’s powered off. At the core of experimental spintronic devices are that can be magnetized in opposite directions to represent the familiar binary states of 1 or 0, and this switching of states can occur very, very quickly. However, there has been a long and arduous search for the best materials for this job, as magnetizing spintronic materials are no simple matter.

Nov 30, 2020

New family of quasiparticles appears in graphene

Posted by in categories: chemistry, computing, mathematics, particle physics

Researchers identify Brown-Zak fermions in superlattices made from the carbon sheet.


Researchers at the University of Manchester in the UK have identified a new family of quasiparticles in superlattices made from graphene sandwiched between two slabs of boron nitride. The work is important for fundamental studies of condensed-matter physics and could also lead to the development of improved transistors capable of operating at higher frequencies.

In recent years, physicists and materials scientists have been studying ways to use the weak (van der Waals) coupling between atomically thin layers of different crystals to create new materials in which electronic properties can be manipulated without chemical doping. The most famous example is graphene (a sheet of carbon just one atom thick) encapsulated between another 2D material, hexagonal boron nitride (hBN), which has a similar lattice constant. Since both materials also have similar hexagonal structures, regular moiré patterns (or “superlattices”) form when the two lattices are overlaid.

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