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Europe officially sets its sights on a giant LHC successor



Enlarge / CERN makes its own superconducting wiring for the successor to the LHC.

The Large Hadron Collider, the most powerful particle collider humanity has ever built, resides in an enormous, 27-kilometer-long tunnel that extends under the Swiss and French countrysides. What’s often overlooked is that the tunnel was built for an earlier piece of hardware, the Large Electron-Positron collider, or LEP. LEP had been built specifically to provide a clean way to study the Z boson; only later was it converted to a higher-energy proton collider that enabled the discovery of the Higgs boson.

Now, Europe is officially committing to taking a similar approach: building a huge tunnel at the CERN facility that will collide particles to enable a clean study of the Higgs boson. But Europe is leaving the option of using the tunnel for a future collider that could reach energies nearly 10 times higher than the LHC.

Electrons vs. hadrons

Electrons and positrons are fundamental particles; as far as we know, they have no smaller particles that comprise them. That makes their collisions extremely clean. The protons collided by the LHC, in contrast, are composed of a collection of quarks and gluons, making their collisions a complicated collection of sub-collisions that can be challenging to interpret.

That makes electrons and positrons better candidates for the detailed characterization of particles. But they’re less good for discovery. As particles are forced to travel around the curved paths of circular colliders, they radiate away some energy, causing them to slow down. This limits the energy that collisions can reach. And that’s why CERN replaced LEP with the Large Hadron Collider; protons, thanks to their larger mass, lose less of their energy in the curves of a circular collider. As such, they can be boosted to much higher energy.

Thus, while the 27km tunnel that houses the LHC was originally built to study the Z boson using electrons and positrons, CERN replaced the hardware with a proton collider to discover the Higgs: the Large Hadron Collider.

But even a tunnel like the 27km one now occupied by the LHC sets limits on what we can do. To pull particles along a curved path, we need magnets that increase in strength as the particles’ energy gets higher. Given that we’re at about the limits of current magnet technology, that means we need a larger tunnel—meaning more gradual curves—to reach higher energies. And Europe’s physics community has now decided it wants to build a much larger tunnel.

Bigger is may be better?

The tunnel would be truly enormous, with a circumference of roughly 100km, meaning a diameter of roughly 30km. That would mean it would pass under the nearby Lake Geneva, requiring much deeper tunnels than those used for the LHC. It would be a major and expensive construction project. But it would potentially get us a two-for-one, just as the tunnels occupied by the LHC did. Initially, an electron-positron collider would be built for a detailed characterization of the Higgs boson.

Then, once that is done to the physics community’s satisfaction, it would be replaced by a proton collider that would allow collisions to reach energies over seven times those reached by the LHC. This could allow detection of much heavier particles than those studied by the LHC—assuming heavier particles exist (more on that in a bit).

The total costs of some of these ideas runs into the tens of billions of dollars, and the document is clear that Europe won’t be doing it on its own—international partners will be critical. And that’s where things get a bit strange, because the potential partners are in the process of considering other projects.

Japan and China

For example, Japan has been suggesting it might be willing to host a proposed alternative to a circular collider, the International Linear Collider, which would also collide electrons and positrons in order to study the Higgs. A linear collider avoids the energy loss associated with forcing particles around a curved path. But circular colliders have the advantage of being able to slowly accelerate particles each time they take a lap around the loop, meaning the acceleration could be much more gradual. Linear colliders have only one chance to accelerate particles as they run down the track toward a collision, so the track has to be much longer to reach the equivalent energies—about 30km for the International Linear Collider.

So, the costs are somewhat lower than a circular collider, but not a lot lower. And a linear collider can’t be repurposed into a high-energy hadron collider afterwards.

While Japan is very interested in hosting this collider, it hasn’t committed to fully funding it and is trying to arrange commitments from other countries to add the rest of the funding. But if that collider goes forward, it would obviate the at least half of the justification for building a giant tunnel at CERN. Yet the report claims that “The timely realisation of the electron-positron International Linear Collider in Japan would be compatible with this strategy.”

Elsewhere, the Chinese are considering a plan that largely mimics that of CERN’s: a giant circular tunnel that will house first an electron-positron collider and, later, a proton collider. China’s argument is that it’s not constrained to build in the complex geography of the Swiss-French border, with its lakes and mountain ranges. And construction costs are lower there to begin with, meaning that the whole project could be done substantially more cheaply in China. Again, no commitment has been made to build the hardware yet, but it could make the arguments for CERN’s project far more complicated if it continues to move forward.

There are also many active areas of study that would enable us to build hardware that provides greater accelerations in shorter distances. The report also argues for continued support of those, even though they would tip the balance heavily in favor of using a linear collider, since it could be made much more compact. There’s an additional mention of using muons, heavier (if unstable) relatives of the electron and positron, for the collisions, something that’s being actively pursued at the US’ Fermilab.

“The European particle physics community must intensify accelerator R&D and sustain it with adequate resources,” the report says, even though progress on any of them would make the big collider a less appealing approach.

A gap in the theory

But perhaps the biggest question facing the collider is whether there’s anything left for it to find. In addition to the Higgs, there were strong theoretical candidates, including potential dark matter particles, that were within the energy range reached by the LHC. Even though none of them turned up, that has ended up being informative, killing off a huge range of potential models for other particles and causing plenty of people to rethink models based on the idea of supersymmetry.

At the moment, in the energies that will be reached by this proposed successor, we have… not a whole lot. There are always ideas floating around that would involve extremely heavy particles, and it’s always possible that potential particles that were predicted to be lighter turn out not to be. But there’s no obvious candidates at these energies that have a well-developed theory behind them. As a result, we’ve got no strong reason to think that there’d be anything to discover if we built this machine.

Of course, we’d have decades of development in theory that might place something there before this actually becomes operational. And there’s always the chance that we’d find something unexpected if it was built. But those chances are not typically the sorts of things that are allowed to dominate the funding landscape for an entire field. Fortunately, the physics community has gotten used to shifting funding priorities over the years, and the construction of the new collider is far enough out that there is time to work out if and how to integrate this work with the proposed projects in Japan and China.

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COVID was the leading cause of death in Americans aged 45-54 in 2021



Enlarge / A woman watches white flags on the National Mall on September 18, 2021 in Washington, DC. Over 660,000 white flags were installed here to honor Americans who have lost their lives to COVID-19 epidemic.

COVID-19 was the third leading cause of death in Americans between March 2020 and October 2021, accounting for one in every eight deaths.

In that time frame, COVID-19 ranked in the top five causes of death for every age group of people older than 15 years. Between January and October 2021, the pandemic disease was the leading cause of death among people 45 to 54 years old.

That’s all according to a study of national death certificate data, published Tuesday in JAMA Internal Medicine by researchers at the National Institutes of Health.

The study found COVID-19 caused roughly 700,000 deaths between March 2020 and October 2021. The pandemic disease trailed only heart disease and cancer, which caused roughly 2.15 million collectively in that time frame. The fourth and fifth deadliest afflictions in the US were accidental deaths—including car crashes, overdoses, and alcohol-related deaths—and stroke, which collectively caused around 624,000 deaths during that period.

The authors, led by Meredith Shiels, an expert in cancer epidemiology and genetics at the National Cancer Institute, broke up the time frame into two sections: the start of the pandemic in March 2020 to December 2020, and January 2021 to October 2021, the last month for which there was complete data. This revealed age-specific trends, likely driven partly by uptake of vaccines and other mitigation efforts.

In the 2020 period, COVID-19 was the second leading cause of death in people aged 85 and over, but, amid high vaccine uptake in this age group, it fell to the third leading cause of death from January to October 2021.

Younger adults saw the opposite trend. For those aged 45 to 54, COVID-19 was the fourth leading cause of death in the 2020 period but jumped to the leading cause of death in 2021. Likewise, in those aged 35 to 44, COVID-19 jumped from the fifth leading cause of death in 2020 to the second leading cause in 2021. And for those aged 15 to 24 and 25 to 34, COVID-19 wasn’t in the top five in 2020, but ranked as the fourth leading cause of death in both age groups in 2021.

For those aged 55 to 84, COVID-19 was the third leading cause of death in both time periods.

The study is limited by the potential for misclassifying deaths on death certificates. But the authors were careful to select a time cutoff that would limit provisional or incomplete data from skewing the findings. That meant, however, that the study did not include deaths from part of the delta wave or the towering omicron wave in January 2022. Since October 2021, around 300,000 additional people in the US have died from COVID-19.

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Russian astronauts use space station to promote anti-Ukraine propaganda



Enlarge / Cosmonauts Oleg Artemyev, Denis Matveyev, and Sergey Korsakov pose with a flag of the Luhansk People’s Republic on the International Space Station.

The Russian state space corporation responsible for spaceflight activities, Roscosmos, on Monday posted images to its official Telegram channel showing three cosmonauts with the tri-color flags of the Luhansk People’s Republic and the Donetsk People’s Republic.

The photos were taken recently on board the International Space Station and show smiling cosmonauts Oleg Artemyev, Denis Matveyev, and Sergey Korsakov posing with the flags.

“This is a long-awaited day that residents of the occupied areas of the Luhansk region have been waiting for eight years,” the Roscosmos message stated. “We are confident that July 3, 2022, will forever go down in the history of the republic.”

The images and social media posting represent the most blatant use of the International Space Station—which is operated by the United States, Russia, Japan, Canada, and the European Space Agency—for Russian propaganda purposes since the invasion of Ukraine.

Luhansk and Donetsk are two breakaway “quasi-states” in the eastern region of Ukraine known as the Donbas. Ukraine and Russia have battled over the two regions since 2014, as Russia has agitated separatists in the Ukrainian territory. The United Nations does not recognize the two “republics,” and Ukraine has designated them as “temporarily occupied territories.” Fighting has heated up since the Russian invasion of Ukraine in February 2022. This past weekend, Russian forces claimed to have established control over the entire Luhansk region.

A professional relationship

NASA and Roscosmos, as well as other space agencies, have continued cooperating on the International Space Station since the invasion began. Some US officials have suggested that NASA should consider breaking ties with Russia in space due to the atrocities in Ukraine. However, the space agency’s administrator has defended the partnership on the basis that the station flies above geopolitical tensions on Earth. NASA also wants to keep flying the station, as breaking the US segment from the Russian segment would be difficult and potentially fatal to the operation of the orbital facility.

In an interview published Monday in the German publication Der Spiegel, NASA Administrator Bill Nelson reiterated this stance.

“In the midst of the Cold War, when the Soviet Union and the United States were mortal enemies and their nuclear weapons could be used at any time, a US and a Soviet spacecraft met in space in 1975,” Nelson said. “Peaceful cooperation continued even after the collapse of the Soviet Union. Our space shuttle docked with the Russian space station Mir. And then we decided to build the International Space Station together. Both countries are needed for operations, the Russians for propulsion, the Americans for power. We will continue to have a very professional relationship between cosmonauts and astronauts to keep this station alive.”

Nevertheless the provocative actions this weekend by Roscosmos, with its cosmonauts celebrating the so-called liberation of Ukrainian territory, brings the bloody conflict on Earth into space. To some observers, such as former NASA astronaut Terry Virts, Russia’s use of the space station for propaganda purposes is unacceptable.

“I am incredibly disappointed to see cosmonauts and Roscosmos using the International Space Station as a platform to promote their illegal and immoral war, where civilians are being killed every day,” said Virts, who flew side by side with Russians and commanded the space station in 2015. “The space station is supposed to be a symbol of peace and cooperation.”

Virts said NASA has largely been trying to look the other way when it comes to Russian actions, most notably when it comes to Roscosmos chief Dmitry Rogozin, who has made numerous jingoistic statements about the war. But in this case, he said, the agency really cannot afford to.

Seat swap

NASA’s cooperation with Russia may come into greater public focus in a couple of months. At present, a NASA astronaut named Frank Rubio is scheduled to fly on a Russian Soyuz spacecraft to the station in September. Around the same time, a Russian cosmonaut named Anna Kikina is due to fly on a SpaceX Crew Dragon vehicle to the station as part of the seat swap. The arrangement has not been formally agreed to by the US and Russian government.

In his German interview, Nelson defended the swap, saying, “It makes a lot of sense for us. You need both Russians and Americans to operate the space station. What happens if something is wrong with one of our spacecraft? We need the other vehicle as a back-up. And that’s why we will continue to have crew exchanges.”

Such an argument may soon ring hollow, however. Boeing’s Starliner spacecraft may make its first crewed test flight before the end of this year, and if it is successful NASA will have two US spacecraft capable of reaching the station.

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How the Yurok Tribe is bringing back the California Condor



Enlarge / The California condor is a New World vulture, the largest North American land bird. This condor became extinct in the wild in 1987, but the species has been reintroduced in California and Arizona.

The first California condor to reach Yurok ancestral land in over a century arrived by plane and car in late March of 2022. The small plane that carried Condor 746 had a rough landing, and the bird was irritable. He rattled around in a large dog crate during the three-hour drive to the tribe’s newly built condor facility, in a remote location in Redwood National Park.

Once there, he hopped into the flight pen, a tall enclosure of wire mesh, furnished with log perches and a drinking pool. At 8 years old, Condor 746 is an adult, his naked head bright pink instead of the black found in younger birds. He’s on loan from the captive breeding program at the Peregrine Fund’s World Center for Birds of Prey in Boise, Idaho. His job is to act as the mentor for four juvenile birds who will become the founders of a reborn condor society in Yurok country.

“We have mentors because condors are so social,” says Joe Burnett, California Condor Recovery Program Manager at the Ventana Wildlife Society. Young birds in a pen with no adult will become unruly. “You get the Lord of the Flies syndrome,” says Burnett. He and his colleagues quickly learned that release programs need an adult to serve as a role model and enforce the social hierarchy that is crucial to the flock’s survival.

A few days after 746 arrived, Condor A0, age 2, entered the flight pen. The first thing she focused on was 746, lounging on a perch. Understanding that she was in a safe place, A0 checked out the food—the carcass of a stillborn calf—then flapped onto a perch and fluffed up her feathers, a sign of avian contentment. Three young male condors, tagged A1, A2, and A3, followed. The youngsters had been living together for months at other condor facilities in Boise, Idaho, and San Simeon, California, and they already felt at home with each other.

Condor, known as prey-go-neesh in the native language, is sacred to the Yurok people. The Yurok reservation lies along the Klamath River in northwest California, but much of the tribe’s ancestral land is now in the hands of government agencies or private landowners. The tribe has been working to bring back the California condor since 2003, when a group of elders identified the bird as a keystone species for both culture and ecology, and therefore the most important land-based creature in need of restoration.

Nineteen years after the Yurok made that bold decision, the condors arrived. Elders who had worked toward that pivotal moment watched as Tiana Williams-Claussen, director of the Yurok Wildlife Department, and her colleagues released each newcomer into the pen.

Williams-Claussen’s job is to understand the details of condor biology and to interpret Yurok culture for the wider world. A tribal member, she grew up on the coast near the mouth of the Klamath, and went off to Harvard University. She didn’t set out to be a condor biologist, but when she returned in 2007 with a degree in biochemical sciences, condor restoration was the work her people needed her to do. Williams-Claussen has since spent 14 years living and breathing condors, learning how to handle them, building partnerships with government agencies, and listening to what Yurok elders have to say about the great bird.

The California condor is a critically endangered species: In the 1980s, the total population dwindled to fewer than 30 individuals. Biologists concluded the species’ only chance of survival lay in capturing every living condor in order to breed the birds in captivity, safe from poisons and power lines.

Reintroducing condors to the wild proved difficult, however, and the process became a dramatic lesson for biologists on the importance of parenting and the slow pace of growing up among these long-lived, highly social birds. Scientists learned that time spent with adults was critical to the behavioral development of young condors. They also found that in a species where adults follow and protect their offspring for a year or more after the birds fledge, youngsters pioneering landscapes empty of condors require lots of human babysitting.

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