Tag Archives: particle

Dead Star and Distant Black Holes Dazzle in X-Rays

Two new views from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, showcase the telescope’s talent for spying objects near and far. One image shows the energized remains of a dead star, a structure nicknamed the “Hand of God” after its resemblance to a hand. Another image shows distant black holes buried in blankets of dust.

“NuSTAR’s unique viewpoint, in seeing the highest-energy X-rays, is showing us well-studied objects and regions in a whole new light,” said Fiona Harrison, the mission’s principal investigator at the California Institute of Technology in Pasadena, Calif. (more…)

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Higgs Boson Discussion Launches UChicago Discovery Series

The long-sought Higgs boson—the particle that endows all elementary particles in the universe with mass—was elusive no longer when scientists at the CERN physics laboratory in Switzerland, discovered it last summer.

The July 4, 2012 announcement of the discovery appealed to both the general public and the media: Fifty-five media organizations and more than one billion television viewers made it an event that couldn’t be missed. Time even dubbed the Higgs boson “Particle of the Year.” (more…)

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How Computers Push on the Molecules They Simulate

Berkeley Lab bioscientists and their colleagues decipher a far-reaching problem in computer simulations

Because modern computers have to depict the real world with digital representations of numbers instead of physical analogues, to simulate the continuous passage of time they have to digitize time into small slices. This kind of simulation is essential in disciplines from medical and biological research, to new materials, to fundamental considerations of quantum mechanics, and the fact that it inevitably introduces errors is an ongoing problem for scientists.

Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have now identified and characterized the source of tenacious errors and come up with a way to separate the realistic aspects of a simulation from the artifacts of the computer method. The research was done by David Sivak and his advisor Gavin Crooks in Berkeley Lab’s Physical Biosciences Division and John Chodera, a colleague at the California Institute of Quantitative Biosciences (QB3) at the University of California at Berkeley. The three report their results in Physical Review X. (more…)

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Researchers Reveal Structure of Carbon’s ‘Hoyle State’

A North Carolina State University researcher has taken a “snapshot” of the way particles combine to form carbon-12, the element that makes all life on Earth possible. And the picture looks like a bent arm.

Carbon-12 can only exist when three alpha particles, or helium-4 nuclei, combine in a very specific way. This combination is known as the Hoyle state. NC State physicist Dean Lee and German colleagues Evgeny Epelbaum, Hermann Krebs and Ulf-G. Meissner had previously confirmed the existence of the Hoyle state using a numerical lattice that allowed the researchers to simulate how the protons and neutrons interact. When the researchers ran their simulations on the lattice, the Hoyle state appeared together with other observed states of carbon-12, proving the theory correct from first principles. (more…)

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How Silver Turns People Blue

Ingesting silver — in antimicrobial health tonics or for extensive medical treatments involving silver — can cause argyria, condition in which the skin turns grayish-blue. Brown researchers have discovered how that happens. The process is similar to developing black-and-white photographs, and it’s not just the silver.

PROVIDENCE, R.I. [Brown University] — Researchers from Brown University have shown for the first time how ingesting too much silver can cause argyria, a rare condition in which patients’ skin turns a striking shade of grayish blue.

“It’s the first conceptual model giving the whole picture of how one develops this condition,” said Robert Hurt, professor of engineering at Brown and part of the research team. “What’s interesting here is that the particles someone ingests aren’t the particles that ultimately cause the disorder.” (more…)

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Fluid Cathedrals: Gels Under the Microscope

ANN ARBOR— A dollop of hair gel might not look like much, but Michigan Engineering researchers have found that it’s a labyrinth of chambers and domes, constructed by the particles inside. These structures allow the gel to hold its shape and determine how much pressure it can withstand before it starts to flow.

While manufacturers currently use trial and error to develop gels with a particular degree of solidity, this discovery could provide a way to design gels for particular applications. (more…)

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A Clock that Will Last Forever

Berkeley Lab Researchers Propose a Way to Build the First Space-Time Crystal

Imagine a clock that will keep perfect time forever, even after the heat-death of the universe. This is the “wow” factor behind a device known as a “space-time crystal,” a four-dimensional crystal that has periodic structure in time as well as space. However, there are also practical and important scientific reasons for constructing a space-time crystal. With such a 4D crystal, scientists would have a new and more effective means by which to study how complex physical properties and behaviors emerge from the collective interactions of large numbers of individual particles, the so-called many-body problem of physics. A space-time crystal could also be used to study phenomena in the quantum world, such as entanglement, in which an action on one particle impacts another particle even if the two particles are separated by vast distances.

A space-time crystal, however, has only existed as a concept in the minds of theoretical scientists with no serious idea as to how to actually build one – until now. An international team of scientists led by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has proposed the experimental design of a space-time crystal based on an electric-field ion trap and the Coulomb repulsion of particles that carry the same electrical charge. (more…)

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UA Climate Scientists Put Predictions to the Test

A new study has found that climate-prediction models are good at predicting long-term climate patterns on a global scale but lose their edge when applied to time frames shorter than three decades and on sub-continental scales.

Climate-prediction models show skills in forecasting climate trends over time spans of greater than 30 years and at the geographical scale of continents, but they deteriorate when applied to shorter time frames and smaller geographical regions, a new study has found.

Published in the Journal of Geophysical Research-Atmospheres, the study is one of the first to systematically address a longstanding, fundamental question asked not only by climate scientists and weather forecasters, but the public as well: How good are Earth system models at predicting the surface air temperature trend at different geographical and time scales? (more…)

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