Large Hadron Collider

Humanity’s Quest to Find New Physics Hinges on a Controversial Particle Smasher

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This next-gen collider could redefine the boundaries of physics, but it comes with an astronomical cost.

as fast as light

  • The European Organization for Nuclear Research, CERN, has put a $21.5 billion price tag on its proposed Future Circular Collider.
  • At more than three times the size of the current Large Hadron Collider, scientists say it is needed to create a more powerful accelerator.
  • Proponents say the possibilities of a sizable collider are too great to understand, but opponents are concerned about the intimidating financial costs.

The Large Hadron Collider still has experiments scheduled into 2040, but CERN—the European Organization for Nuclear Research—already has plans to iterate on the LHC and making something much bigger: the Future Circular Collider.

And bigger might be an understatement.

The proposed $21.5 billion Future Circular Collider (FCC) would “push the energy and intensity frontiers of particle colliders, with the aim of reaching collision energies of 100 TeV, in the search for new physics,” CERN wrote. Expected to have a 56-mile circumference, compared to the 16.5 of the LHC, it would be able to handle energy levels about seven times those of the LHC.

“The FCC will not only be a wonderful instrument to improve our understanding of fundamental laws of physics and of nature,” CERN director general Fabiola Gianotti said during a briefing, according to the Financial Times, “it will also be a driver of innovation.” Much like the LHC before it.

The LHC, an underground circular tunnel near the border between Switzerland and France, started smashing subatomic particles together at nearly the speed of light in 2008. The force it generates is greater than anywhere else in the world, and it allows scientists to study extremely hard-to-observe collisions. In 2012, the LHC helped confirm a 1964 theory about the existence of a fundamental particle called the Higgs boson, a.k.a. the “God particle.” And while there hasn’t been a monumental breakthrough of that magnitude in the last decade, the world’s largest collider is an ongoing lab for physics experiments that simply wouldn’t be possible if the collider didn’t exist.

But even the LHC has its limits. For those physicists who believe colliders can potentially teach us about things like dark matter or about how particles gain mass, the LHC just might not be hefty enough to do the job. That’s where the FCC steps in—three times larger and seven times more powerful.

The FCC, carved deeper underground in the same region, would be built in two phases. The first would begin colliding electrons together in the 2040s. If all goes well, the second phase could begin smashing protons in the 2070s, using powerful magnets not yet invented. All of this would open up a fresh wave of potential experiments.

While it’s almost all upsides in the world of physics, the FCC does have its downsides—namely, its financial cost. The $21.5 billion is just for construction, and doesn’t account for things like operational expenses.

Proponents say that’s the price for science, but not everyone is on board. David King, a former UK government chief scientific advisor, told the BBC that spending that kind of money on the FCC is “reckless.” He believes that with so many other more pressing issues facing our world—such as the current climate emergency—research should focus on helping to manage our future.

Sabine Hossenfelder, of the Munich Center for Mathematical Philosophy, has a similar sentiment. She told the BBC that particle physics research has ballooned well beyond what’s needed—about 10 times the size of what it warrants.

But for those on the particle search, the FCC represents the gateway to the next frontier. “It is a tool that will allow humanity to make enormous steps forward in answering questions in fundamental physics about our knowledge of the universe,” Gianotti said, according to the BBC. “And to do that we need a more powerful instrument to address these questions.”

We’ll soon see if officials decide that the potential benefits outweigh the costs.

What No New Particles Means for Physics

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Physicists are confronting their “nightmare scenario.” What does the absence of new particles suggest about how nature works?

Physicists at the Large Hadron Collider (LHC) in Europe have explored the properties of nature at higher energies than ever before, and they have found something profound: nothing new.

It’s perhaps the one thing that no one predicted 30 years ago when the project was first conceived.

The infamous “diphoton bump” that arose in data plots in December has disappeared, indicating that it was a fleeting statistical fluctuation rather than a revolutionary new fundamental particle. And in fact, the machine’s collisions have so far conjured up no particles at all beyond those catalogued in the long-reigning but incomplete “Standard Model” of particle physics. In the collision debris, physicists have found no particles that could comprise dark matter, no siblings or cousins of the Higgs boson, no sign of extra dimensions, no leptoquarks — and above all, none of the desperately sought supersymmetry particles that would round out equations and satisfy “naturalness,” a deep principle about how the laws of nature ought to work.

“It’s striking that we’ve thought about these things for 30 years and we have not made one correct prediction that they have seen,” said Nima Arkani-Hamed, a professor of physics at the Institute for Advanced Study in Princeton, N.J.

The news has emerged at the International Conference on High Energy Physics in Chicago over the past few days in presentations by the ATLAS and CMS experiments, whose cathedral-like detectors sit at 6 and 12 o’clock on the LHC’s 17-mile ring. Both teams, each with over 3,000 members, have been working feverishly for the past three months analyzing a glut of data from a machine that is finally running at full throttle after being upgraded to nearly double its previous operating energy. It now collides protons with 13 trillion electron volts (TeV) of energy — more than 13,000 times the protons’ individual masses — providing enough raw material to beget gargantuan elementary particles, should any exist.

The Large Hadron Collider collides protons at high energies, and the debris is recorded by two main detectors, CMS and ATLAS. In December 2015, both detectors picked up a small excess in the number of pairs of photons with a combined energy of 750 GeV produced during 13-TeV collisions, when compared to Standard Model predictions. Physicists hoped that this “diphoton bump” resulted from a new elementary particle momentarily forming and then decaying into two photons. Four times more data has been collected at the LHC in 2016, and the diphoton bump has gone away. This indicates that the excess seen last year was merely a statistical fluctuation. (Note that expectations based on the Standard Model have changed slightly in 2016 because of different accelerator and detector conditions.)

Lucy Reading-Ikkanda for Quanta Magazine

So far, none have materialized. Especially heartbreaking for many is the loss of the diphoton bump, an excess of pairs of photons that cropped up in last year’s teaser batch of 13-TeV data, and whose origin has been the speculation of some 500 papers by theorists. Rumors about the bump’s disappearance in this year’s data began leaking in June, triggering a community-wide “diphoton hangover.”

“It would have single-handedly pointed to a very exciting future for particle experiments,” said Raman Sundrum, a theoretical physicist at the University of Maryland. “Its absence puts us back to where we were.”

The lack of new physics deepens a crisis that started in 2012 during the LHC’s first run, when it became clear that its 8-TeV collisions would not generate any new physics beyond the Standard Model. (The Higgs boson, discovered that year, was the Standard Model’s final puzzle piece, rather than an extension of it.) A white-knight particle could still show up later this year or next year, or, as statistics accrue over a longer time scale, subtle surprises in the behavior of the known particles could indirectly hint at new physics. But theorists are increasingly bracing themselves for their “nightmare scenario,” in which the LHC offers no path at all toward a more complete theory of nature.

Some theorists argue that the time has already come for the whole field to start reckoning with the message of the null results. The absence of new particles almost certainly means that the laws of physics are not natural in the way physicists long assumed they are. “Naturalness is so well-motivated,” Sundrum said, “that its actual absence is a major discovery.”

Missing Pieces

The main reason physicists felt sure that the Standard Model could not be the whole story is that its linchpin, the Higgs boson, has a highly unnatural-seeming mass. In the equations of the Standard Model, the Higgs is coupled to many other particles. This coupling endows those particles with mass, allowing them in turn to drive the value of the Higgs mass to and fro, like competitors in a tug-of-war. Some of the competitors are extremely strong — hypothetical particles associated with gravity might contribute (or deduct) as much as 10 million billion TeV to the Higgs mass — yet somehow its mass ends up as 0.125 TeV, as if the competitors in the tug-of-war finish in a near-perfect tie. This seems absurd — unless there is some reasonable explanation for why the competing teams are so evenly matched.

Supersymmetry, as theorists realized in the early 1980s, does the trick. It says that for every “fermion” that exists in nature — a particle of matter, such as an electron or quark, that adds to the Higgs mass — there is a supersymmetric “boson,” or force-carrying particle, that subtracts from the Higgs mass. This way, every participant in the tug-of-war game has a rival of equal strength, and the Higgs is naturally stabilized. Theorists devised alternative proposals for how naturalness might be achieved, but supersymmetry had additional arguments in its favor: It caused the strengths of the three quantum forces to exactly converge at high energies, suggesting they were unified at the beginning of the universe. And it supplied an inert, stable particle of just the right mass to be dark matter.

“We had figured it all out,” said Maria Spiropulu, a particle physicist at the California Institute of Technology and a member of CMS. “If you ask people of my generation, we were almost taught that supersymmetry is there even if we haven’t discovered it. We believed it.”

Hence the surprise when the supersymmetric partners of the known particles didn’t show up — first at the Large Electron-Positron Collider in the 1990s, then at the Tevatron in the 1990s and early 2000s, and now at the LHC. As the colliders have searched ever-higher energies, the gap has widened between the known particles and their hypothetical superpartners, which must be much heavier in order to have avoided detection. Ultimately, supersymmetry becomes so “broken” that the effects of the particles and their superpartners on the Higgs mass no longer cancel out, and supersymmetry fails as a solution to the naturalness problem. Some experts argue that we’ve passed that point already. Others, allowing for more freedom in how certain factors are arranged, say it is happening right now, with ATLAS and CMS excluding the stop quark — the hypothetical superpartner of the 0.173-TeV top quark — up to a mass of 1 TeV. That’s already a nearly sixfold imbalance between the top and the stop in the Higgs tug-of-war. Even if a stop heavier than 1 TeV exists, it would be pulling too hard on the Higgs to solve the problem it was invented to address.

The Standard Model

Lucy Reading-Ikkanda for Quanta Magazine

“I think 1 TeV is a psychological limit,” said Albert de Roeck, a senior research scientist at CERN, the laboratory that houses the LHC, and a professor at the University of Antwerp in Belgium.

Some will say that enough is enough, but for others there are still loopholes to cling to. Among the myriad supersymmetric extensions of the Standard Model, there are more complicated versions in which stop quarks heavier than 1 TeV conspire with additional supersymmetric particles to counterbalance the top quark, tuning the Higgs mass. The theory has so many variants, or individual “models,” that killing it outright is almost impossible. Joe Incandela, a physicist at the University of California, Santa Barbara, who announced the discovery of the Higgs boson on behalf of the CMS collaboration in 2012, and who now leads one of the stop-quark searches, said, “If you see something, you can make a model-independent statement that you see something. Seeing nothing is a little more complicated.”

Particles can hide in nooks and crannies. If, for example, the stop quark and the lightest neutralino (supersymmetry’s candidate for dark matter) happen to have nearly the same mass, they might have stayed hidden so far. The reason for this is that, when a stop quark is created in a collision and decays, producing a neutralino, very little energy will be freed up to take the form of motion. “When the stop decays, there’s a dark-matter particle just kind of sitting there,” explained Kyle Cranmer of New York University, a member of ATLAS. “You don’t see it. So in those regions it’s very difficult to look for.” In that case, a stop quark with a mass as low as 0.6 TeV could still be hiding in the data.

Experimentalists will strive to close these loopholes in the coming years, or to dig out the hidden particles. Meanwhile, theorists who are ready to move on face the fact that they have no signposts from nature about which way to go. “It’s a very muddled and uncertain situation,” Arkani-Hamed said.

New Hope

Many particle theorists now acknowledge a long-looming possibility: that the mass of the Higgs boson is simply unnatural — its small value resulting from an accidental, fine-tuned cancellation in a cosmic game of tug-of-war — and that we observe such a peculiar property because our lives depend on it. In this scenario, there are many, many universes, each shaped by different chance combinations of effects. Out of all these universes, only the ones with accidentally lightweight Higgs bosons will allow atoms to form and thus give rise to living beings. But this “anthropic” argument is widely disliked for being seemingly untestable.

In the past two years, some theoretical physicists have started to devise totally new natural explanations for the Higgs mass that avoid the fatalism of anthropic reasoning and do not rely on new particles showing up at the LHC. Last week at CERN, while their experimental colleagues elsewhere in the building busily crunched data in search of such particles, theorists held a workshop to discuss nascent ideas such as the relaxion hypothesis — which supposes that the Higgs mass, rather than being shaped by symmetry, was sculpted dynamically by the birth of the cosmos — and possible ways to test these ideas. Nathaniel Craig of the University of California, Santa Barbara, who works on an idea called “neutral naturalness,” said in a phone call from the CERN workshop, “Now that everyone is past their diphoton hangover, we’re going back to these questions that are really aimed at coping with the lack of apparent new physics at the LHC.”

Arkani-Hamed, who, along with several colleagues, recently proposed another new approach called “Nnaturalness,” said, “There are many theorists, myself included, who feel that we’re in a totally unique time, where the questions on the table are the really huge, structural ones, not the details of the next particle. We’re very lucky to get to live in a period like this — even if there may not be major, verified progress in our lifetimes.”

As theorists return to their blackboards, the 6,000 experimentalists with CMS and ATLAS are reveling in their exploration of a previously uncharted realm. “Nightmare, what does it mean?” said Spiropulu, referring to theorists’ angst about the nightmare scenario. “We are exploring nature. Maybe we don’t have time to think about nightmares like that, because we are being flooded in data and we are extremely excited.”

There’s still hope that new physics will show up. But discovering nothing, in Spiropulu’s view, is a discovery all the same — especially when it heralds the death of cherished ideas. “Experimentalists have no religion,” she said.

Some theorists agree. Talk of disappointment is “crazy talk,” Arkani-Hamed said. “It’s actually nature! We’re learning the answer! These 6,000 people are busting their butts and you’re pouting like a little kid because you didn’t get the lollipop you wanted?”

CERN Scientists Say The LHC Has Confirmed Two New Particles, And Possibly Discovered a Third

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They are known as bottom baryons.

The Large Hadron Collider is at it again, showing us new wonders in the world of particle physics. Scientists working on the Large Hadron Collider beauty (LHCb) collaboration have observed two new particles that have never been seen before – and seen evidence of a third.

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The two new particles, predicted by the standard quark model, are baryons – the same family of particles as the protons used in LHC particle acceleration experiments.

Baryons are what most of the Universe is made up of, including protons and neutrons – composite particles consisting of three fundamental particles called quarks, which have different ‘flavours’, or types: up, down, top, bottom, charm, and strange.

Protons consist of two up quarks and one down quark, while neutrons consist of one up quark and two down quarks, for instance. But the two new particles discovered have a slightly different composition.

Named Σb(6097)+ and Σb(6097)–, they consist of two up quarks and one bottom quark; and two down quarks and one bottom quark, respectively.

These particles are known as bottom baryons, and they are related to four particles previously observed at Fermilab. However, the new observations mark the first time scientists have detected these higher-mass counterparts; they are about six times more massive than a proton.

So what’s the third particle candidate we mentioned earlier?

The researchers think it might be a strange type of composite particle called a tetraquark. These are an exotic kind of meson, which normally have two quarks. But a tetraquark is composed of four quarks – well, two quarks and two antiquarks, to be more accurate.

Observational evidence of tetraquarks has been pretty elusive to date, and that is also the case here. Evidence of the candidate particle, called Zc–(4100) and including two heavy charm quarks, was detected in the decay of heavier B mesons.

But the detection only had a significance of over 3 standard deviations. The usual threshold to claim the discovery of a new particle is 5 standard deviations. It will take future observations to either confirm or disprove the existence of Zc–(4100).

The new bottom baryons, you’ll be pleased to know, blew that threshold out of the water: Σb(6097)+ and Σb(6097)– had significances of 12.7 and 12.6 standard deviations respectively.

Particle Physicists Turn to AI to Cope with CERN’s Collision Deluge

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Can a competition with cash rewards improve techniques for tracking the Large Hadron Collider’s messy particle trajectories?

Particle Physicists Turn to AI to Cope with CERN's Collision Deluge
A visualization of complex sprays of subatomic particles, produced from colliding proton beams in CERN’s CMS detector at the Large Hadron Collider near Geneva, Switzerland in mid-April of 2018. Credit: CERN

Physicists at the world’s leading atom smasher are calling for help. In the next decade, they plan to produce up to 20 times more particle collisions in the Large Hadron Collider (LHC) than they do now, but current detector systems aren’t fit for the coming deluge. So this week, a group of LHC physicists has teamed up with computer scientists to launch a competition to spur the development of artificial-intelligence techniques that can quickly sort through the debris of these collisions. Researchers hope these will help the experiment’s ultimate goal of revealing fundamental insights into the laws of nature.

At the LHC at CERN, Europe’s particle-physics laboratory near Geneva, two bunches of protons collide head-on inside each of the machine’s detectors 40 million times a second. Every proton collision can produce thousands of new particles, which radiate from a collision point at the centre of each cathedral-sized detector. Millions of silicon sensors are arranged in onion-like layers and light up each time a particle crosses them, producing one pixel of information every time. Collisions are recorded only when they produce potentially interesting by-products. When they are, the detector takes a snapshot that might include hundreds of thousands of pixels from the piled-up debris of up to 20 different pairs of protons. (Because particles move at or close to the speed of light, a detector cannot record a full movie of their motion.)

From this mess, the LHC’s computers reconstruct tens of thousands of tracks in real time, before moving on to the next snapshot. “The name of the game is connecting the dots,” says Jean-Roch Vlimant, a physicist at the California Institute of Technology in Pasadena who is a member of the collaboration that operates the CMS detector at the LHC.

After future planned upgrades, each snapshot is expected to include particle debris from 200 proton collisions. Physicists currently use pattern-recognition algorithms to reconstruct the particles’ tracks. Although these techniques would be able to work out the paths even after the upgrades, “the problem is, they are too slow”, says Cécile Germain, a computer scientist at the University of Paris South in Orsay. Without major investment in new detector technologies, LHC physicists estimate that the collision rates will exceed the current capabilities by at least a factor of 10.

Researchers suspect that machine-learning algorithms could reconstruct the tracks much more quickly. To help find the best solution, Vlimant and other LHC physicists teamed up with computer scientists including Germain to launch the TrackML challenge. For the next three months, data scientists will be able to download 400 gigabytes of simulated particle-collision data—the pixels produced by an idealized detector—and train their algorithms to reconstruct the tracks.

Participants will be evaluated on the accuracy with which they do this. The top three performers of this phase hosted by Google-owned company Kaggle, will receive cash prizes of US$12,000, $8,000 and $5,000. A second competition will then evaluate algorithms on the basis of speed as well as accuracy, Vlimant says.

Prize appeal

Such competitions have a long tradition in data science, and many young researchers take part to build up their CVs. “Getting well ranked in challenges is extremely important,” says Germain. Perhaps the most famous of these contests was the 2009 Netflix Prize. The entertainment company offered US$1 million to whoever worked out the best way to predict what films its users would like to watch, going on their previous ratings. TrackML isn’t the first challenge in particle physics, either: in 2014, teams competed to ‘discover’ the Higgs boson in a set of simulated data (the LHC discovered the Higgs, long predicted by theory, in 2012). Other science-themed challenges have involved data on anything from plankton to galaxies.

From the computer-science point of view, the Higgs challenge was an ordinary classification problem, says Tim Salimans, one of the top performers in that race (after the challenge, Salimans went on to get a job at the non-profit effort OpenAI in San Francisco, California). But the fact that it was about LHC physics added to its lustre, he says. That may help to explain the challenge’s popularity: nearly 1,800 teams took part, and many researchers credit the contest for having dramatically increased the interaction between the physics and computer-science communities.

TrackML is “incomparably more difficult”, says Germain. In the Higgs case, the reconstructed tracks were part of the input, and contestants had to do another layer of analysis to ‘find’ the particle. In the new problem, she says, you have to find in the 100,000 points something like 10,000 arcs of ellipse. She thinks the winning technique might end up resembling those used by the program AlphaGo, which made history in 2016 when it beat a human champion at the complex game of Go. In particular, they might use reinforcement learning, in which an algorithm learns by trial and error on the basis of ‘rewards’ that it receives after each attempt.

Vlimant and other physicists are also beginning to consider more untested technologies, such as neuromorphic computing and quantum computing. “It’s not clear where we’re going,” says Vlimant, “but it looks like we have a good path.”

For all book lovers please visit my friend’s website.
URL: http://www.romancewithbooks.com

Particle Physicists Turn to AI to Cope with CERN’s Collision Deluge

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Can a competition with cash rewards improve techniques for tracking the Large Hadron Collider’s messy particle trajectories?

Particle Physicists Turn to AI to Cope with CERN's Collision Deluge
A visualization of complex sprays of subatomic particles, produced from colliding proton beams in CERN’s CMS detector at the Large Hadron Collider near Geneva, Switzerland in mid-April of 2018.

Physicists at the world’s leading atom smasher are calling for help. In the next decade, they plan to produce up to 20 times more particle collisions in the Large Hadron Collider (LHC) than they do now, but current detector systems aren’t fit for the coming deluge. So this week, a group of LHC physicists has teamed up with computer scientists to launch a competition to spur the development of artificial-intelligence techniques that can quickly sort through the debris of these collisions. Researchers hope these will help the experiment’s ultimate goal of revealing fundamental insights into the laws of nature.

At the LHC at CERN, Europe’s particle-physics laboratory near Geneva, two bunches of protons collide head-on inside each of the machine’s detectors 40 million times a second. Every proton collision can produce thousands of new particles, which radiate from a collision point at the centre of each cathedral-sized detector. Millions of silicon sensors are arranged in onion-like layers and light up each time a particle crosses them, producing one pixel of information every time. Collisions are recorded only when they produce potentially interesting by-products. When they are, the detector takes a snapshot that might include hundreds of thousands of pixels from the piled-up debris of up to 20 different pairs of protons. (Because particles move at or close to the speed of light, a detector cannot record a full movie of their motion.)

From this mess, the LHC’s computers reconstruct tens of thousands of tracks in real time, before moving on to the next snapshot. “The name of the game is connecting the dots,” says Jean-Roch Vlimant, a physicist at the California Institute of Technology in Pasadena who is a member of the collaboration that operates the CMS detector at the LHC.

After future planned upgrades, each snapshot is expected to include particle debris from 200 proton collisions. Physicists currently use pattern-recognition algorithms to reconstruct the particles’ tracks. Although these techniques would be able to work out the paths even after the upgrades, “the problem is, they are too slow”, says Cécile Germain, a computer scientist at the University of Paris South in Orsay. Without major investment in new detector technologies, LHC physicists estimate that the collision rates will exceed the current capabilities by at least a factor of 10.

Researchers suspect that machine-learning algorithms could reconstruct the tracks much more quickly. To help find the best solution, Vlimant and other LHC physicists teamed up with computer scientists including Germain to launch the TrackML challenge. For the next three months, data scientists will be able to download 400 gigabytes of simulated particle-collision data—the pixels produced by an idealized detector—and train their algorithms to reconstruct the tracks.

Participants will be evaluated on the accuracy with which they do this. The top three performers of this phase hosted by Google-owned company Kaggle, will receive cash prizes of US$12,000, $8,000 and $5,000. A second competition will then evaluate algorithms on the basis of speed as well as accuracy, Vlimant says.

Prize appeal

Such competitions have a long tradition in data science, and many young researchers take part to build up their CVs. “Getting well ranked in challenges is extremely important,” says Germain. Perhaps the most famous of these contests was the 2009 Netflix Prize. The entertainment company offered US$1 million to whoever worked out the best way to predict what films its users would like to watch, going on their previous ratings. TrackML isn’t the first challenge in particle physics, either: in 2014, teams competed to ‘discover’ the Higgs boson in a set of simulated data (the LHC discovered the Higgs, long predicted by theory, in 2012). Other science-themed challenges have involved data on anything from plankton to galaxies.

From the computer-science point of view, the Higgs challenge was an ordinary classification problem, says Tim Salimans, one of the top performers in that race (after the challenge, Salimans went on to get a job at the non-profit effort OpenAI in San Francisco, California). But the fact that it was about LHC physics added to its lustre, he says. That may help to explain the challenge’s popularity: nearly 1,800 teams took part, and many researchers credit the contest for having dramatically increased the interaction between the physics and computer-science communities.

TrackML is “incomparably more difficult”, says Germain. In the Higgs case, the reconstructed tracks were part of the input, and contestants had to do another layer of analysis to ‘find’ the particle. In the new problem, she says, you have to find in the 100,000 points something like 10,000 arcs of ellipse. She thinks the winning technique might end up resembling those used by the program AlphaGo, which made history in 2016 when it beat a human champion at the complex game of Go. In particular, they might use reinforcement learning, in which an algorithm learns by trial and error on the basis of ‘rewards’ that it receives after each attempt.

Vlimant and other physicists are also beginning to consider more untested technologies, such as neuromorphic computing and quantum computing. “It’s not clear where we’re going,” says Vlimant, “but it looks like we have a good path.”

For all book lovers please visit my friend’s website.
URL: http://www.romancewithbooks.com

CERN May Have Evidence of a Quasiparticle We’ve Been Hunting For Decades

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Meet the elusive odderon.

The Large Hadron Collider (LHC) is the particle accelerator that just keeps on giving, and recent experiments at the site suggest we’ve got the first evidence for a mysterious subatomic quasiparticle that, until now, was only a hypothesis.

Quasiparticles aren’t technically particles, but they act like them in some respects, and the newly recorded reactions point to a particular quasiparticle called the odderon.

It already has a name because physicists have been on its theoretical trail for the past 40 years.

Now, they still haven’t seen the elusive odderon itself, but researchers have now observed certain effects that hint the quasiparticle really is there.

That would in turn give us new information to feed into the Standard Model of particle physics, the guidebook that all the building blocks of physical matter are thought to follow.

“This doesn’t break the Standard Model, but there are very opaque regions of the Standard Model, and this work shines a light on one of those opaque regions,” says one of the team, particle physicist Timothy Raben from the University of Kansas.

“These ideas date back to the 70s, but even at that time it quickly became evident we weren’t close technologically to being able to see the odderon, so while there are several decades of predictions, the odderon has not been seen.”

The reactions studied in this case involve quarks, or electrically charged subatomic particles, and gluons, which act as exchange particles between quarks and enable them to stick together to form protons and neutrons.

In proton collisions where the protons remain intact, up until now scientists have only seen this happen when an even number of gluons are exchanged between different protons. The new research notes, for the first time, these reactions happening with an odd number of gluons.

And it’s the way the protons deviate rather than break that’s important for this particular area of investigation. It was this phenomena that first led to the idea of a quasiparticle called an odderon, to explain away collisions where protons survived.

“The odderon is one of the possible ways by which protons can interact without breaking, whose manifestations have never been observed .. this could be the first evidence of that,” Simone Giani, spokesperson at the TOTEM experiment of which this is a part, told Ryan F. Mandelbaum at Gizmodo.

It’s a pretty complex idea to wrap your head around, so the researchers have used a vehicle metaphor to explain what’s going on.

“The protons interact like two big semi-trucks that are transporting cars, the kind you see on the highway,” explains Raben.

“If those trucks crashed together, after the crash you’d still have the trucks, but the cars would now be outside, no longer aboard the trucks – and also new cars are produced. Energy is transformed into matter.”

“Until now, most models were thinking there was a pair of gluons – always an even number… We found measurements that are incompatible with this traditional model of assuming an even number of gluons.”

What all of that theoretical physics and subatomic analysis means is that we may have seen evidence of the odderon at work – with the odderon being the total contribution produced from the exchange of an odd number of gluons.

The experiments involved a team of over 100 physicists, colliding billions of proton pairs together every second in the LHC. At its peak, data was being collected at 13 teraelectronvolts (TeV), a new record.

By comparing these high energy tests with results gleaned from other tests run on less powerful hardware, the researchers could reach a new level of accuracy in their proton collision measurements, and that may have revealed the odderon.

Ultimately this kind of super-high energy experiment can feed into all kinds of areas of research, including medicine, water purification, and cosmic ray measuring.

We’re still waiting for confirmation that this legendary quasiparticle has in fact been found – or at least that its effects have – and the papers are currently submitted to be published in peer reviewed journals.

But it’s definitely a super-exciting time for physicists.

“We expect big results in the coming months or years,” says one of the researchers, Christophe Royon from the University of Kansas.

The research is currently undergoing peer review, but you can read the studies on the ArXiv.org and CERN pre-print servers.

The Real Science of the God Particle in Netflix’s ‘The Cloverfield Paradox’

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Even if you’re not a particle physics buff, you may have noticed that the plot of Netflix’s surprise Superbowl Sunday release, The Cloverfield Paradox, relies heavily on a huge physics discovery that was in the news a few years ago: the Higgs Boson particle.

The Cloverfield Paradox

Also known as the “God particle” — which happened to be the working title of the new J.J. Abrams film — the Higgs Boson was first observed directly by scientists in 2012.

Gratuitous spoilers for The Cloverfield Paradox ahead.

In the midst of an energy crisis in the year 2028, scientists are struggling to use a massive space-based particle accelerator to help efficiently produce energy. When they finally get it to accelerate particles, they suddenly find themselves on the opposite side of the sun from the Earth. Chaos ensues: Worms explode out of a guy. Someone’s arm rematerializes on the other side of the ship with a mind of its own. Standard body horror nonsense.

Long story short, we’re led to believe that this botched experiment is what brought monsters to Earth in the first Cloverfield film — which, given the crazy science that goes on at the European Organization for Nuclear Research (CERN), is not totally absurd.

Cloverfield Paradox Monster
In ‘The Cloverfield Paradox,’ we’re led to believe that a particle accelerator experiment gone wrong in 2028 messed up the multiverse and caused a monster attack in 2008.

Any good science fiction story has some basis in reality, and it’s clear that The Cloverfield Paradox drew heavily on conspiracy theories that sprung up around CERN and its efforts to find direct evidence of the Higgs-Boson particle using a 27-kilometer circumference accelerator, the Large Hadron Collider.

 The particle’s discovery was a big deal because it was the only one out of 17 particles predicted by the Standard Model of particle physics that had never been observed. The Higgs Boson is partly responsible for the forces between objects, giving them mass.

But it wasn’t the particle itself that conspiracy theorists and skeptics worried about. It’s the way physicists had to observe it.

Doing so involved building the LHC, an extraordinarily large real-life physics experiment that housed two side-by-side high-energy particle beams traveling in opposite directions at close to the speed of light. The hope was that accelerated protons or lead ions in the beam would collide, throwing off a bunch of extremely rare, short-lived particles, one of which might be the Higgs Boson. In 2012, scientists finally observed it, calling it the “God particle” because “Goddamn particle” — as in “so Goddamn hard to find” — was considered too rude to print.

Critics and skeptics argued that colliding particles at close to the speed of light increased the potential to accidentally create micro black holes and possibly even larger black holes, leading to wild speculation like that in Cloverfield Paradox.

cloverfield paradox
Ah yes, the elusive Hands Bosarm particle.

This has never happened in real life, of course, and there’s also strong evidence that it couldn’t happen. Check out this excerpt from an interaction between astrophysicist Neil deGrasse Tyson and science skeptic Anthony Liversidge that Gizmodo reported on in 2011:

NDT: To catch everybody up on this, there’s a concern that if you make a pocket of energy that high, it might create a black hole that would then consume the Earth. So I don’t know what papers your fellow read, but there’s a simple calculation you can do. Earth is actually bombarded by high energy particles that we call cosmic rays, from the depths of space moving at a fraction of the speed of light, energies that far exceed those in the particle accelerator. So it seems to me that if making a pocket of high energy would put Earth at risk of black holes, then we and every other physical object in the universe would have become a black hole eons ago because these cosmic rays are scattered across the universe are hitting every object that’s out there. Whatever your friend’s concerns are were unfounded.

Liversidge may be on the fringe with his argument, but he isn’t alone. As Inverse previously reported, Vanderbilt University physicist Tom Weiler, Ph.D., has hypothesized that a particle created alongside the Higgs Boson, called the Higgs singlet, could travel through time through an as-yet-undiscovered fifth dimension. If Weiler’s hypothesis is correct, then it seems possible that interdimensional travel, as depicted in Cloverfield Paradox, could be possible, though his model really only accounts for the Higgs singlet particle’s ability to time travel.

'The Cloverfield Paradox' is forever the most important Cloverfield.
In ‘The Cloverfield Paradox,’ a particle accelerator plays a central role.

The reason the Cloverfield Paradox scientists were trying to fire up a particle accelerator in space is just as speculative. While particle accelerators take a massive amount of energy to accelerate their beams to near light speed, some physicists argue that under certain conditions, a particle accelerator could actually produce energy. Using superconductors, they argued, it would be possible for a particle accelerator to actually produce plutonium that could be used in nuclear reactors. So in a sense, the science of the movie is kind of based on maybe possibly real science.

That being said, this space horror film takes extreme liberties, even where it’s based on real science. Even on the extreme off-chance that any of the hypotheses outlined in this article turned out to be true, the tiny potential side effects of particle accelerators are nothing like what we see in The Cloverfield Paradox.

The Hunt For Elusive Single-Pole Magnets Just Became More Challenging

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A search through a mountain of data from the Large Hadron Collider for particles called magnetic monopoles has once again come up empty handed.

That doesn’t yet completely rule out the possibility of these hypothetical objects. But it does tell us that if they exist, they might be extraordinarily massive particles that are beyond our ability to create.

 

Magnetic monopoles are often explained as being a particle that represents a single pole of a magnet – something nobody has ever seen so far.

If you slice a magnet in half, you still get an object with a north pole and a south pole. No matter how tiny you make the thing, you won’t get an isolated pole.

Not that this stops physicists from looking: the story of the magnetic monopole dates back to the equations of the theoretical physicist James Clerk Maxwell.

He mathematically showed that we could swap electric for magnetic fields and not see any real difference – in other words, the two were symmetrical.

That only works for their fields, though. Electrical currents have charges, which are points that exist in a vector, meaning the current flows in a direction.

If we have magnetic fields that are symmetrical with electric fields, why not magnetic points that also flow along a vector? Finding one would tell us a lot about their electrical twin as well.

So the search was on for magnetic points that were the equivalent of a charge – the magnetic monopole.

Not everybody is convinced they exist. Last year, physicists argued that the symmetry between electricity and magnetism is broken at a deep, fundamental level. Still, for many optimists, the search continues.

“A lot of people think they should exist,” says particle physicist James Pinfold from the University of Alberta in Edmonton, Canada.

He and his team have just trawled through a pile of data from the Monopole and Exotics Detector at the LHC (MoEDAL). And they came up with nothing.

Their research was published recently on the pre-print website arXiv.org, which means we need to be cautious in not reading too deeply until it gets published in a peer-reviewed journal.

But the fact they had six times the information as previous efforts involving MoEDAL, and also took into consideration monopoles with a different kind of spin to previous analyses, shows how much ground has been covered.

In some ways this is a good thing – the research further narrows down where the monopole might be hiding. Crashing protons together at ridiculous speeds is just one way we might be able to make magnetic monopoles.

Another team of physicists from Imperial College London took a slightly different approach to searching for the elusive particles, publishing their results in the journal Physical Review Letters last December.

Part of the problem as they saw it was if monopoles were being produced inside particle colliders, there was every chance they’d be strongly stuck together.

What was needed was another way to narrow down the kinds of properties they might have, and then compare those with MoEDAL’s results.

To do this they considered how magnetic monopoles might appear inside intense, hot magnetic fields, just like those surrounding a type of neutron star called a magnetar.

If their mass was small enough, their magnetic charge would affect the star’s magnetic field.

Of course, even the strength of the monopole’s charge is hypothetical at the moment, but based on a few reasonable assumptions they calculated we could expect the particle’s mass to be more than about the third of that of a proton.

That’s not exactly tiny. And if the actual charge is heavier than the smallest one imaginable, that mass goes up.

Either way we look at it, physicists are needing to consider two possibilities; either the magnetic monopole is a myth, and the fractured symmetry between electricity and magnetism is a fundamental part of nature; or this thing is big.

It’s possible we just might need bigger colliders. It’s also possible magnetic monopoles are so heavy, only something as monumental as a Big Bang could produce them, leaving us to hunt for relics.

Only one thing is for certain – the hunt continues

The Large Hadron Collider Just Detected a New Particle That’s Heavier Than a Proton

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The Large Hadron Collider has once again done what it does best – smash bits of matter together and find new particles in the carnage.

This time physicists have come across a real charmer. It’s four times heavier than a proton and could help challenge some ideas about how this kind of matter sticks together.

 We’ve seen a lot of interesting new particles from CERN’s Large Hadron Collider “beauty” (LHCb) collaboration, which is a little sister to the ATLAS and CMS experiments that brought us the famous Higgs boson a few years back.

The experiments run in CERN’s colliders all involve accelerating matter and then bringing it to a quick stop. The resulting burst of energy results in a shower of particles with different properties, most of which we’re pretty familiar with.

Running these experiments over and over again and doing the maths on the sizes and behaviours of the particles as they form and interact with one another can occasionally provide something different.

We can now officially add a new kind of baryon to the zoo of particles, one that was already predicted to exist but never before seen.

The two baryons you’re no doubt most familiar with are the ones that make up an atom’s nucleus, called protons and neutrons.

Baryons are effectively triplets of smaller particles called quarks, which are elementary particles meaning they aren’t made up of anything smaller themselves.

 Quarks come in a variety of flavours, oddly called up, down, top, bottom, charm, and strange. It’s combinations of these that give us different bosons. Current models predict there are a bunch of ways quarks can make baryons, with some more common than others.

Protons consist of two ups and a down quark, while neutrons are two downs and an up. These quarks stick together under what’s called the strong nuclear force, which is caused by the swapping of particles called gluons. Never let it be said that physicists lack a sense of humour.

This new baryon – made when two charm quarks and a single up bound together – was given the less whimsical name Xi cc++, so they can’t all be winners.

Quarks have different masses, and charm is a beefy one. That makes this baryon a touch on the heavy side, which is good news for particle physicists.

“Finding a doubly heavy-quark baryon is of great interest as it will provide a unique tool to further probe quantum chromodynamics, the theory that describes the strong interaction, one of the four fundamental forces,” said Giovanni Passaleva, the spokesperson for the LHCb collaboration.

Seeing how this particle keeps itself together compared to the predictions made by current models will help give the going theories a good shake.

 Being made of two heavy quarks should give Xi cc++ a slightly different structure to protons and neutrons.

“In contrast to other baryons, in which the three quarks perform an elaborate dance around each other, a doubly heavy baryon is expected to act like a planetary system, where the two heavy quarks play the role of heavy stars orbiting one around the other, with the lighter quark orbiting around this binary system,” says former collaboration spokesperson Guy Wilkinson.

If you’re wondering where this baryon has been hiding all this time, like many particles it doesn’t hang around very long. It wasn’t seen directly, but was recognised by the particles it broke into.

The LHCb experiment is a champion at spotting these kinds of decay products, as well as making heavy quarks.

The discovery has a high statistical significance at 7 sigma. Physicists break out the champagne at 5 sigma, so we can be pretty confident Xi cc++ was produced.

If you’re playing Standard Model bingo, that’s one more to cross off your list.

Tetraquark Evidence Mounts with Help from the Large Hadron Collider

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IN BRIEF

Physicists working with the Large Hadron Collider have found an entire set of particles with four heavy quarks, further confirming the existence of tetraquarks. The four structures do not follow the characteristics of particles dictated by pre-existing laws of physics.

“IT’S THE FIRST TIME WE’VE SEEN THIS”

While technically protons have tons of quarks (and anti-quarks), three of those quarks, known as valence quarks, make up the positive charge of a proton. Hence, the three-quark label.

Throughout the history of physics, we have been familiar with two and three-quark particles. This made the recent discovery of four-quark particles called tetraquarks, and five-quark particles or pentaquarks, a slow uphill battle as it is met with severe skepticism. In 2003, the Belle experiment in Japan first observed particles in a four-quark state but lacked sufficient evidence to definitively prove it. Belle, Fermilab, and other research facilities since have announced similar observations, but none have been able to provide irrefutable proof of their existence.

Tetraquark in comparison with ordinary matter. Credit: Nature
In 2014, the Large Hadron Collider finally confirmed tetraquarks, and now has identified four more of these particles—a discovery that stands as solid evidence that would permanently cement their existence. “It was a long road to get here,” says University of Iowa physicist Kai Yi of the Collider Detector at Fermilab (CDF) and Columbia-MIT-Fermilab (CMF) experiments.

The exotic particles are named based on their respective masses in mega-electronvolts: X(4140), X(4274), X(4500) and X(4700). They are each composed entirely of heavy quarks: two charm quarks and two strange quarks arranged in a unique way, each with a different internal structure by mass and quantum numbers. “The quarks inside these particles behave like electrons inside atoms,” says Syracuse University physics professor Tomasz Skwarnicki says. “They can be ‘excited’ and jump into higher energy orbitals. The energy configuration of the quarks gives each particle its unique mass and identity.”

 “What we have discovered is a unique system,” Skwarnicki continues. “We have four exotic particles of the same type; it’s the first time we have seen this and this discovery is already helping us distinguish between the theoretical models.”

ARE THEY EVEN PARTICLES?

Our current laws of physics cannot explain this groundbreaking discovery. “We looked at every known particle and process to make sure these four structures couldn’t be explained by any pre-existing physics. It was like baking a six-dimensional cake with 98 ingredients and no recipe—just a picture of a cake,” Syracuse University researcher Thomas Britton says.

The researchers are now working on models that would help make sense of these new particles, which may not even be particles, as they do not behave in accordance with our standard models of particles. “The molecular explanation does not fit with the data,” Skwarnicki adds. “But I personally would not conclude that these are definitely tightly bound states of four quarks. It could be possible that these are not even particles. The result could show the complex interplays of known particle pairs flippantly changing their identities.”

The bizarre particles (or whatever else they may eventually turn out to be) are possibly heralding a new era of expansion for quantum physics, thanks to the Large Hadron Collider. “The huge amount of data generated by the LHC is enabling a resurgence in searches for exotic particles and rare physical phenomena,” Britton says. “There’s so many possible things for us to find and I’m happy to be a part of it.”