Thursday, October 28, 2021

Is the Great Neutrino Puzzle Pointing to Multiple Missing Particles?

 

In 1993, the Liquid Scintillator Neutrino

Detector at Los Alamos National Laboratory

reported a puzzling bounty of neutrino detections.

 

In 1993, deep underground at Los Alamos National Laboratory in New Mexico, a few flashes of light inside a bus-size tank of oil kicked off a detective story that is yet to reach its conclusion.

 

The Liquid Scintillator Neutrino Detector (LSND) was searching for bursts of radiation created by neutrinos, the lightest and most elusive of all known elementary particles. “Much to our amazement, that’s what we saw,” said Bill Louis, one of the experiment’s leaders.

 

The problem was that they saw too many. Theorists had postulated that neutrinos might oscillate between types as they fly along — a hypothesis that explained various astronomical observations. LSND had set out to test this idea by aiming a beam of muon neutrinos, one of the three known types, toward the oil tank, and counting the number of electron neutrinos that arrived there. Yet Louis and his team detected far more electron neutrinos arriving in the tank than the simple theory of neutrino oscillations predicted.

 

Since then, dozens more neutrino experiments have been built, each grander than the last. In mountains, disused mining caverns and the ice beneath the South Pole, physicists have erected cathedrals to these notoriously slippery particles. But as these experiments probed neutrinos from every angle, they kept yielding conflicting pictures of how the particles behave. “The plot keeps thickening,” said Louis. (Full Story)

 

 

Understanding the towering ‘fire clouds’ over forest blazes

 

Courtesy photo.

 

Across Northern New Mexico, it’s been a hazy summer and early fall for all to see — and smell. Much of that smoke was blown here by winds from the Bootleg Fire, which raged across south-central Oregon, and the Dixie Fire, which scorched Northern California. As these blazes obliterated hundreds of thousands of acres of forest, the roiling flames launched massive smoke plumes high into the atmosphere.

 

Typically, the smoke has been lofted to a few miles above ground, and then picked up and carried by wind currents across the country, much like weather fronts that carry moisture and bring rain to blanket New York City and the eastern seaboard in a thick haze.

 

But the Bootleg Fire also sent up a towering vertical plume lofting smoke to a record-breaking 10 miles. Intensely hot fires from dense fuels, local weather conditions and dry surface and high-altitude atmospheric clouds conspired to cause the plume to rise far above ordinary clouds.

 

When you see these pyrocumulonimbus, you know you’ve got big trouble below. These clouds are so intense that they modify local weather and create amazing lightning storms that can ignite more fires.

 

In recent years, megafires and their blanketing haze have become an increasingly familiar sight, along with the towering thunderheads of smoke that form above them. Yet we’re only beginning to learn what causes those awe-inspiring “fire clouds,” what’s in them and what effects they have on weather and climate.

 

Through a combination of field observations, experimental work in the laboratory and computer modeling at local to global scales, our team at Los Alamos National Laboratory is making progress in understanding the mechanisms and climate impacts of pyrocumulonimbus from recent megafires in British Columbia (2017) and Australia (2019-20). (Full story)

 

 

 

Major US and European labs join forces to tackle climate change

 

  

Waste heat from the European Spallation Source will

eventually be connected to the local heating system

rather than being vented into the atmosphere

(courtesy: Perry Nordeng/ESS).

 

Top physics facilities in Europe and the US have come together to tackle the climate crisis. The labs – including CERN, the European Space Agency, Fermilab and the Los Alamos National Laboratory – have announced that they will step up their scientific collaboration on carbon-neutral energy and climate change as well as share best practices to improve the carbon footprint of big-science facilities.

 

Large labs demand a huge amount of energy. The CERN particle-physics lab near Geneva, for example, uses 1.3 terawatt hours of electricity annually, which is enough to power 300,000 UK homes for a year. In 2020 the lab released its first public Environment Report that detailed the status of CERN’s environmental footprint. It found that greenhouse-gas emissions emitted by the lab in 2018 was 223,800 tonnes of carbon-dioxide equivalent.

 

Planned facilities, such as the European Spallation Source that is being constructed in Lund, Sweden, meanwhile, have integrated sustainability into their design such as diverting waste heat into local heating systems instead of it being vented into the atmosphere. (Full story)

 

 

 

New Results from MicroBooNE Provide Clues to Particle Physics Mystery

 

MicroBooNE detector being lowered into the

experimental facility at Fermilab. Photo Courtesy Fermilab.

 

New results from a more-than-decade long physics experiment offer insight into unexplained electron-like events found in previous experiments. Results of the MicroBooNE experiment, while not confirming the existence of a proposed new particle, the sterile neutrino, provide a path forward to explore physics beyond the Standard Model, the theory of the fundamental forces of nature and elementary particles.

 

“The results so far from MicroBooNE make the explanation for the MiniBooNE experiment’s anomalous electron-like events more likely to be physics beyond the Standard Model,” said William Louis, physicist at Los Alamos National Laboratory and a member of the MicroBooNE collaboration. “What exactly the new physics is – that remains to be seen.”

 

The MicroBooNE experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory explores a striking anomaly in particle beam experimentation first uncovered by researchers at Los Alamos National Laboratory. In the 1990s, the Liquid Scintillator Neutrino Detector experiment at the Laboratory saw more electron-like events than expected, compared to Standard Model-based calculations. (Full story)

 

 

Also from the Los Alamos Reporter:

 

Improved DOE Exascale Earth System Model Two Times Faster Than Previous Version

 

High-resolution E3SM simulation over the Arctic showing

surface ocean currents and temperatures (blue) and

January sea-ice concentration (gray/white).

 

A new version of the Department of Energy’s Energy Exascale Earth System Model (E3SM) is two times faster than its earlier version released in 2018, allowing for more accurate and timely simulations of the changing climate.

 

“This version of E3SM is faster and more capable than the first,” said Los Alamos National Laboratory scientist Luke Van Roekel, who co-leads the Water Cycle science campaign for the project.

 

“From one version to another, earth system models typically become better but also quite a bit slower, so both faster and better is significant. The improved fidelity and increased capability in physics and regional resolution position us to begin answering critical questions related to DOE’s mission.”

 

Earth system models have weather-scale resolution and use advanced computers to simulate aspects of Earth’s variability and anticipate decadal changes that will critically impact the U.S. energy sector in coming years. These critical factors include regional air/water temperatures, which can strain energy grids; water availability, which affects power plant operations; extreme water-cycle events (floods and droughts), which impact infrastructure and bio-energy; and sea-level rise and coastal flooding, which threaten coastal infrastructure. (Full story)

 

Friday, October 22, 2021

 


The coronavirus is still mutating. But will that matter? ‘We need to keep the respect for this virus.’

This electron microscope image shows
coronavirus particles. Courtesy photo.
 
Coronavirus infections are down across much of the United States. Hospitalizations, too. Deaths are finally dropping from their dismaying late-summer peak of more than 2,000 a day. Most people are vaccinated, and booster shots are gaining approval. Officials in the United States are hoping the worst of the pandemic is over.
 
But so much depends on the virus itself. It is not static. It mutates. Delta, the variant of SARS-CoV-2 now causing virtually all infections in the United States, is more than twice as transmissible as the virus that emerged in Wuhan, China. The possibility of further significant mutations in the virus looms like a giant asterisk over any discussion of the trajectory of the pandemic.
 
The first significant change in the virus was identified by Bette Korber, a theoretical biologist at the Los Alamos National Laboratory in New Mexico. She had been scrutinizing the genomes of virus samples from around the world and noticed that one mutation, known as D614G, had become common in the virus in dozens of geographic locations. This mutation altered the positioning of the virus’s spike protein — its tool for binding to cells.
 
Korber, in collaboration with researchers at Duke University and the University of Sheffield in England, concluded that the strain with the mutation was more transmissible than the first strain that circulated in China. They posted their findings online — and slammed into a wall of scientific skepticism.
 
No one today doubts that the coronavirus is capable of evolving rapidly — and dangerously — as it spreads through the human population. It is a generalist virus — able to infect many different mammals. It has been known to jump from humans into minks and back into humans. Zookeepers are coping with infections among lions, tigers, gorillas and other captive animals. (Full story)
 
 
 
Physicists make most precise measurement ever of neutron’s lifetime
 
The magnet array for the UCNτ experiment at
Los Alamos National Laboratory.
 
Physicists have measured the lifetime of the neutron more precisely than ever before.
 
The average time it takes for the subatomic particle to decay is 877.75 seconds, according to an experiment that used magnetic fields to trap ultra-cold neutrons. The results have twice the precision of similar measurements, and are consistent with theoretical calculations. But they do not explain why in an alternative kind of experiment, neutrons last nearly 10 seconds longer.
 
The latest measurement was presented at a virtual meeting of the American Physical Society on 13 October, and published in Physical Review Letters1.
 
Exactly how long it takes for a neutron to decay is random, but the average time is about a quarter of an hour. To get a precise value, Daniel Salvat, an experimental nuclear physicist at Indiana University in Bloomington, and his colleagues built an experiment called UCNτ at the Los Alamos National Laboratory in New Mexico. They slowed neutrons down to ultra-cold temperatures and placed them in a vacuum ‘bottle’, a metal structure shaped like the halfpipe in skateboarding. Magnetic fields at the bottom of the bottle prevented the neutrons from touching the surface, where they would have been lost. (Full story)
 
Also reported in Gizmodo.
 
 
 
NASA releases incredible audio captured by its Perseverance rover on Mars
 
 
Nasa releases incredible audio captured by 
Perseverance rover on Mars.
 
NASA’s Perseverance rover has recorded five hours of sounds from Mars and scientists said it made them feel as if they were “right there on the surface.”
 
The rover now has the unique distinction of becoming the first spacecraft to record the sounds of the Red Planet through dedicated microphones, according to a press release issued by the space agency on Monday.
 
“Sound on Mars carries much farther than we thought. It shows you just how important it is to do field science,” said Nina Lanza, a SuperCam scientist working with mic data at the Los Alamos National Laboratory (LANL) in New Mexico.
 
“We’ve all seen these beautiful images that we get from Mars but having sound to be able to add to those images, it makes me feel like I’m almost right there on the surface,” said Lanza in a video released by NASA. (Full story)
 
 
 
7
Bacteria, fungi interact far more often than previously thought
 
A diverse culture collection of fungal isolates
obtained from around the world has been
screened by researchers for potential bacterial
associates.
 
In a novel, broad assessment of bacterial-fungal interactions, researchers using unique bioinformatics found that fungi host a remarkable diversity of bacteria, making bacterial-fungal interactions far more common and diverse than previously known.
 
"Until now, examples of bacterial-fungal interactions were pretty limited in number and diversity," said Aaron Robinson, a biologist at Los Alamos National Laboratory and lead author of a new paper describing the research in Nature's Communications Biology journal. "It had been assumed that bacterial-fungal associations might not be that common. But we found a lot of diverse bacteria that appear to associate with fungi, and we detected those associations at a frequent rate."
 
The research contributes to an emerging understanding of the fungal bacteriome, the existence of bacteria both within and in close association with a fungal host, opening up possibilities for studying the interactions more intimately and connecting that research to issues such as ecosystem functioning and climate change impacts. (Full story)
 
 
 
NASA Perseverance mission shows flash floods on Mars