What No New Particles Means for Physics


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?”

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


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 LHC Disproves the Existence of Ghosts and the Paranormal


IN BRIEF
  • Renowned physicist Brian Cox has claimed that the lack of any physical evidence being detected by the highly sensitive Large Hadron Collider disproves the existence of ghosts.
  • Four in 10 Americans reportedly believe in ghosts, a figure that belies the lack of scientific evidence behind their existence.

THE LHC

Looks like the Ghostbusters have some competition, and it’s renowned physicist and science communicator Brian Cox. But rather than bust some ghosts, it looks like he’s more in the business of destroying the idea of the paranormal entirely. He wasn’t just looking to spread some knowledge to the 4 in 10 Americans who believe in ghosts, though — he was sharing a simple conclusion he has reached by working with the Large Hadron Collider (LHC).

The LHC is the largest and most powerful particle accelerator that humanity has ever built. It features a ring 27 kilometers (16 miles) long with superconducting magnets and accelerating structures specifically built to boost the energy of particles that scientists hope to study. Within the accelerator, two high-energy beams are forced to collide from opposite directions at speeds close to the speed of light. A good analogy for this would be firing two needles toward each other from 10 kilometers (6 miles) apart with a precision that makes sure they meet halfway.

Over 10,000 scientists and engineers from over 100 countries work together at this structure below the France-Switzerland border to help us learn about the fundamental properties of physics. They test different properties of elementary particles, and thus far, they have learned about particle decay, found hints of new particles, and reexamined what we know about the Big Bang. It’s from this evidence-based research that Brain Cox believes he can dismiss the existence of the paranormal entirely.

NO EVIDENCE, NO GHOSTS

Brian Cox made the claim during a recent broadcast of BBC Radio Four’s “The Infinite Monkey Cage” that focused on the intersection of science and the paranormal:

If we want some sort of pattern that carries information about our living cells to persist then we must specify precisely what medium carries that pattern and how it interacts with the matter particles out of which our bodies are made. We must, in other words, invent an extension to the Standard Model of Particle Physics that has escaped detection at the Large Hadron Collider. That’s almost inconceivable at the energy scales typical of the particle interactions in our bodies.

Neil deGrasse Tyson, who was also on the show, went on to press him for a clarification: “If I understand what you just declared, you just asserted that CERN, the European Center for Nuclear Research, disproved the existence of ghosts.” Cox replied with a simple “Yes.”

Cox’s point relies heavily on the LHC’s ability to pick up the tiniest bursts of energy found in particle collisions. That mean that any energy signatures from paranormal entities should be easy to detect. Thus far, no such evidence has been found. Does this mean that you can no longer enjoy horror movies? No, it just means you don’t have to be scared.

Watch the video. URL:

Will the LHC Prove the Existence of Higher Dimensions?


In Brief
  • To achieve an accurate description of the universe, physical theories are increasingly invoking extra dimensions to explain the mysteries of nature.
  • The problem is—how do you prove the existence of something so elusive? New experiments with the LHC may finally prove just how many extra dimensions, if any, our universe really has.

How many dimensions are there? Is time a dimension? Or is our 3-dimensional space-time just one element—and a minor one at that—of a greater hyperdimensional universe?

It’s a question that’s been asked many, many times, and the answers can be almost as varied as there are potential extra dimensions. From Paul Ehrenfest’s exploration of 3-dimensional physics in 1917 to the M-theory of the 1990s, experts throughout the years have proposed their own answers—some more forcefully than others.

But with advances in technology, and armed with new mathematical models and theories, we might be in a unique position today to begin to understand one of the natural world’s most baffling mysteries.

Dimensions, Gravity, and Light

At the heart of almost all theories that deal with the number of dimensions are the fundamental forces of gravity and light, both of which are possibly the most observed and easily the most studied phenomena in the physical universe. Among the four fundamental forces in nature—the others being the strong and weak nuclear forces—gravity and electromagnetism (which is responsible for generating light) are the trickiest to deal with. Individually, they’ve caused grief to countless scientists and theorists; and when put together, they wreak absolute havoc.

Models generally draw from these observable features of the universe to build theories and conjectures about how things work. The simpler ones proposed that the universe was made up of three dimensions: length, width, and depth. This is especially easy to grasp since it’s how we perceive the world; it’s intuitive and entirely logical.

Illustration of gravity leaking from space-time
Illustration of gravity leaking from space-time “branes” into the hyperdimensional “bulk.”

But this neat, trinary division of the universe doesn’t exactly sum up how we experience it. To build on this, some mathematicians—notably Hermann Minkowski—combined the three spatial dimensions with a fourth, temporal dimension, to construct a space-time description of reality.

This is where things start to become knotty. There are embarrassing discrepancies and inconsistencies that just don’t seem to tally. For instance, why does gravity operate on such a massive scale—planets, stars, galaxies—whereas the other forces act upon such a tiny scale? Or, put somewhat differently, why is gravity so much weaker than the other four fundamental forces?

In an interesting essay for PBS, Paul Halpern illustrates the problem using a simple example: “Pick up a steel thumbtack with a tiny kitchen magnet, and see how its attraction overwhelms the gravitational pull of the entire earth.”

So a number of theories were evolved to attempt to compensate for these discrepancies. Building on the work of Theodor Kaluza and Oskar Klein in the 1920s, superstring theories advanced the idea that the vibrations of minuscule energy strings were responsible for all that we observe in nature; these theories only worked, however, in a universe comprising ten or more dimensions, with the extra six or so all “compactified” into a tiny space beyond the limits of ready observation.

Another approach (M-theory) subsumed this 10-dimensional universe, composed of strings and energetic membranes, within a large, potentially observable extra dimension called the “bulk.” In this notion, matter and energy and most of the fundamental forces cling timidly to the energetic space-time membranes, or “branes;” gravity, however, is something of a free agent, operating alike on the branes and within the hyperdimensional bulk. For this reasons, gravitons—the carriers of gravitational energy—can bleed off in to the bulk, diminishing the small-scale strength of gravity but still allowing it to exert undue power over large distances.

A Large Hadron Collision of Ideas

Enter the Large Hadron Collider. The machine, based in Geneva, Switzerland, just might hold the answer to the dimensional puzzle. Capable of running extremely high-energy particle collisions, experts are able to construct specialized experiments which might, in turn, yield data that point to theories that actually hold water.

Right now, scientists are looking for three specific occurrences to prove that higher dimensions exist: the presence of massive particle traces, sort of like reverberating echoes; missing energy caused by gravitons migrating to higher dimensions; and microscopic black holes.

Ongoing experiments will explore these possibilities, just as scientists are hotly pursuing an elusive theory that unifies all the laws of the universe. If the volume of discoveries in recent years is an indicator, then we just might be closer than we ever thought.

 

A ‘New Physics’? Scientists May Have Glimpsed a World Beyond the Standard Model


Physicists are using the LHC to probe for elementary particles that may exist beyond the Standard Model. By doing so, they may discover (and may have already discovered) a “new physics” that has a real chance to resolve some of the greatest mysteries in science.
MESON, FERMIONS, LEPTONS, AND BOSONS

The Standard Model, which emerged in the 1970s, is a theoretical foundation that explains the world and matter at the very smallest levels of reality: elementary particles so minute they boggle the imagination and defy easy understanding.  It has been a pretty successful description so far, but like most old foundations, it’s beginning to show signs of cracks and disrepair.

Of course, it’s not so much that the standard model is wrong; rather, there may be a deeper kind of physics, a dark sector that we haven’t been able to reach yet.

In other words, there are hints of something greater and even more fundamental shining through those cracks like glinting rays of sunshine.  And a team of physicists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN), working with the LHC particle accelerator at CERN, think they may be on the track of what that “something” is.

Briefly, the Standard Model divides matter and the forces of the universe into several categories of elementary particles.  Pay attention now, reader, because this will go quickly.  Bosons transmit force; photons (light) emerge from electromagnetic activity; eight species of gluon are involved in the strong nuclear force (holding atoms together); and the W+, W- and Z0 bosons oversee the weak nuclear force (responsible for radioactive decay).  Matter comprises fermions, which are formed by quarks and leptons; there are six species of quarks, and six of leptons (which include electrons and neutrinos), together with 12 antiparticles for each.  The Higgs boson provides mass for all, save the gluons and photons.

Got that?  Good.

But here’s the problem—the Standard Model, in common with other theories explaining the universe (such as Quantum Mechanics and General Relativity), is not quite as comprehensive as we’d like it to be.  It fails to explain some of the most interesting and pressing questions confronting physics.

For instance, it doesn’t account for the division of fermions into different families, or why matter achieved the upper hand over antimatter in the early universe.  And if dark matter is indeed an actual form of “matter,” it is not explained by our current understanding of elementary particles.  Perhaps most importantly, gravity (that most mysterious and fundamental of forces) is utterly unaccounted for by the Standard Model.

Highly complicated, graphical analysis of the decay of a "beauty" meson into a kaon and two muons. Credit: CERN
Highly complicated, graphical analysis of the decay of a “beauty” meson into a kaon and two muons. 
THE BEAUTY MESON

The Large Hadron Collider has turned its considerable particle-smashing heft to the task of seeking out new elementary particles beyond the Standard Model; but it’s possible they exist just outside the energy limit of the LHC.  If this is the case, then the only way to discover their presence will be to discern their “shadow,” as it were—the influence they exert upon other particles at lower energies.

And one way this might work is if they cause “mesons”—unstable, short-lived combinations of a quark and antiquark—to decay in unusual and unexpected ways.

This is what the team believes it may have found. A few years back, the LHCb experiment, which probes the mysteries of matter and antimatter, detected anomalous readings in the decay of a B meson or “beauty” meson—a meson consisting of a light quark and a heavy beauty antiquark.  It was necessary to rig up a more accurate method of determining the parameters by which the beauty quark decayed in order to test its deviation from the Standard Model; the Polish team devised a means to determine the parameters independently.

According to Dr. Marcin Chrzaszcz of IFJ PAN, one of the authors of the new research, “[m]y approach can be likened to determining the year when a family portrait was taken. Rather than looking at the whole picture, it is better to analyze each person individually and from that perspective try to work out the year the portrait was taken.”

By more accurately determining the degree of deviation from the Standard Model, scientists will be able to ascertain whether the anomaly really represents the influence of unknown elementary particles beyond the Model, or whether it is merely some hitherto undiscovered property which the Model does account for.

For now, physicists hypothesize that there is something called a “Z-prime” (Z’) boson, which mediates the decay of B mesons.  The LHC is gearing up now for new, higher-energy collisions. Perhaps, at last, they’ll discover the new particles, and the new physics, they’ve been searching for.

What No New Particles Means for Physics


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

[No Caption]
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.

 

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.

 

Maria Spiropulu of the California Institute of Technology, pictured in the LHC’s CMS control room, brushed aside talk of a nightmare scenario, saying, “Experimentalists have no religion.”

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 particlesdidn’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.

 

“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,” explainedKyle 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.

 

Nima Arkani‐Hamed discussing theoretical physics with a colleague at the Institute for Advanced Study in Princeton, N.J.

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?”

Hope for a New Particle Fizzles at the LHC


A curious signal of a potentially revolutionary new particle detected last year turned out to be a fluke.

A portion of the ATLAS detector, one of the two massive experiments at the Large Hadron Collider that reported—and have now refuted—what could have been a revolutionary new subatomic particle. 

For months, the world of physics has been abuzz with rumors about a potential new subatomic particle that could revolutionize our entire view of physics. But new results presented today by physicists from the Large Hadron Collider (LHC) today have, for now, quashed the revolution.

The first hints of a new particle appeared in December 2015, when two independent experiments at the LHC, ATLAS and CMS, each announced the same tantalizing quirk in their data. Both experiments smash together protons at nearly the speed of light, searching for new fundamental particles produced by the enormously energetic collisions. When they ramped up to their highest energies yet, the two experiments detected a mysterious signal: more pairs of photons with a combined energy of 750 giga-electron volts (GeV) than expected.

This “diphoton bump” was not a prediction of the Standard Model of physics—a rigorously tested and profoundly successful theory forged in the 1970s that incorporates all known fundamental particles and forces. Despite its success, however, the Standard Model does not explain what lies at the hearts of black holes, the nature of dark matter and dark energy, the quantum behavior of gravity, and other deep mysteries of the universe. With their shared diphoton bumps, ATLAS and CMS appeared on the verge of peering into physics beyond the Standard Model’s musty confines. Within weeks, the little bump had inspired hundreds of speculative papers by theorists. “At the LHC, physicists are looking very intensively for new particles and new laws of physics so it’s easy to get excited about something that seems very convincing,” says Michael Peskin, a theoretical physicist at Stanford’s SLAC National Accelerator Laboratory.

Whatever produced the diminutive diphoton bump didn’t neatly fit into any theory. Many scientists suggested that the bump was produced by a heavier cousin of the Higgs boson, another particle that similarly showed up as an eyebrow-raising blip in the data about four years ago. Others suggested that it could be a kind of dark matter particle, or even the vaunted graviton, the predicted carrier particle for gravity itself.

But as scientists at the LHC started collecting more data this year, the 750 GeV diphoton bump started disappearing. Now, after analyzing nearly five times the amount of data that they had last year, ATLAS and CMS physicists have watched the bump diminish to statistical insignificance. Presenting at the International Conference on High Energy Physics in Chicago, particle physicist and ATLAS spokesperson Dave Charlton said that when looking at all the data, the 750GeV signal now only has a significance of 2 sigma, which is much less than the 5 sigma (or 1 in 3.5 million chance) that is needed to confirm a new discovery in physics. Simply put, the diphoton bump was a false alarm. “It is a bit surprising that we saw the fluctuation on both instruments but it was just that—a fluctuation or statistical fluke,” said Charlton.

Seeing anomalies in the data is not uncommon at the LHC. The collider crashes so many protons together and churns out so much raw data that occasionally finding extra pairs of photons in the wreckage was bound to happen. “If you conduct many, many searches you come across these kinds of coincidences,” says Guy Wilkinson, a member of the LHCb collaboration.

Although the diphoton bump has now evaporated under closer scrutiny, researchers remain optimistic that the LHC will still lead them to new physics beyond the Standard Model. The multibillion-dollar project has years of operations left during which it will produce far more data for physicists to parse for elusive new particles. “We would have been very lucky if we found something, some new phenomenon or some new state of matter at this early stage,” says CMS physicist Tiziano Camporesi. “But we have to be patient.”

 

LHC creates liquid from Big Bang


Wow, this is amazing, maybe we will be closer from understanding the universe than ever.

Scientists using the Large Hadron Collider (LHC) have produced tiny droplets of a state of matter thought to have existed right at the birth of the universe.

An international team at the Large Hadron Collider (LHC) have produced quark-gluon plasma — a state of matter thought to have existed right at the birth of the universe — with fewer particles than previously thought possible. The results were published in the journal APS Physics on June 29, 2015.

The Large Hadron Collider is the world’s largest and most powerful particle accelerator. The LHC, located in a tunnel between Lake Geneva and the Jura mountain range on the Franco-Swiss border, is the largest machine in the world. The supercollider was restarted this spring (April 2015) following two years of intense maintenance and upgrade. Take a virtual tour of the LHC here.

The new material was discovered by colliding protons with lead nuclei at high energy inside the supercollider’s Compact Muon Solenoid detector. Physicists have dubbed the resulting plasma the “littlest liquid.”

So, the Big bang was not solid, but liquid??? Did i get ir right, this is a very interesting stuff.


Quan Wang is a University of Kansas researcher working with the team at CERN, the European Organization for Nuclear Research. Wang described quark-gluon plasma as a very hot and dense state of matter of unbound quarks and gluons — that is, not contained within individual nucleons. He said:

It’s believed to correspond to the state of the universe shortly after the Big Bang.

While high-energy particle physics often focuses on detection of subatomic particles, such as the recently discovered Higgs Boson, the new quark-gluon-plasma research instead examines behavior of a volume of such particles.

Wang said such experiments might help scientists to better understand cosmic conditions in the instant following the Big Bang.

Large Hadron Collider Created A Portal To Another Dimension?


As U.I.P stated recently, the bizarre UFO sighting in the sky above the Netherlands, looks VERY much like a Portal than anything else! Could it be that the Large Hadron Collider (LHC) has opened up a Portal in the sky to Another Dimension?

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Could it be that this image of a most bizarre looking object snapped up high above the Netherlands, could be the first ever picture of a portal to another dimension? Possibly opened up by the guys based in CERN

The Gentleman who caught this incredible sighting was Dutch snapper Harry Perton, who was photographing stormy evening skies at the tome over Groningen in his homeland, when all of a sudden there was a HUGE flash as he fired the shutter! Some people believe that this very well could be a wormhole to another Dimension.

Harry Perton's astonishing original picture

Harry Perton’s astonishing original picture

I am sure that a lot of you reading this will already know this, but Wormholes are a VERY mysterious scientific theory that there are openings in space-time to another part of the universe or even another dimension. It is very important to remember when discussing Portals/wormholes, that they are actually very real and even our silent friends in NASA not so long confirmed their existence

At the time he took the picture, Mr Perton actually did not realise anything out of the ordinary had just happened, and instead believing it must have been a flash of lightening instead. Little did he know that he may of taken one of the most important photos of all time…

It was only until a short while later after taking the photographs , when he reviewed the shots at home, he could actually see the strange semi-translucent object shaped like an upside down jellyfish or toadstool…..or Portal!

NASA's image or what a Portal could look like.

NASA’s image or what a Portal could look like.

The REAL thing!?

The REAL thing!?

You can clearly see that most of the object is a turquoise like colour, while there is a sunlight-esque jet or beam of light at the base…..Or an entrance to a portal to another Dimension!?

Not surprisingly, after this incredible photo was posted online, it led to a complete frenzy of speculation, which included whether it could be proof of wormholes, Project Blue Beam, alien visitations or even some kind of a religious warning to the people of this world. But the most popular theory was ‘could this be a portal to another Dimension?’

Has a new door for mankind been opened

Has a new door for mankind been opened

One commentator said about this whole strange event the:

“That’s a portal, it allows a craft to travel from one end of the universe to the other in a matter of secontnds. Someone made a mistake when entering our system and basically got caught. What you’re seeing is a craft entering not leaving.”

Many others immediately speculated that this could be the result of the Large Hadron Collider LHC being turned back on at twice its original power AND what with the confirmation off the guys at CERN that they are starting to look for other Universes/Dimensions!

Somebody else immediately posted: “It’s a wormhole.”

As we all know, the LHC is a massive atom smashing machine which scientists are now using to unlock secrets of the universe, which also includes whether parallel universes exist.

Many critics around the world now fear that CERN is tampering way too much with the laws of physics as they have already admitted that it could create a man made ‘mini’ black hole or even a wormhole – a mysterious theoretical portal through space-time to another part of the universe or even to another dimension….It really is like something from your wildest dreams and imagination as a child isn’t it!

Mr Perton officially responded to the amount of interest his image had gained around the world and said:

“I was taking photos and suddenly something flashed.

“I decided it must have been a strike of lightning ­ but back at home I saw something strange in one of the photos that I took ­what looked like a UFO.”

Quite a few other people online posted and decided that this could be a fighter jet sonic boom, or even a sign of the Second coming…or a sign of the End of days being not too far away! (well we did hear the sounds of the Trumpets in the sky across the world not so long ago).

One person in Malta has actually claimed that a whole football team saw it, and then adding:”We where playing a football game in Malta and all the 16 players saw it on 26th Tuesday around 8.05pm.”

Another claimed to have seen the same thing six years ago in Wales. Whilst others pointed out the Norway Spiral could be a similar oddity in the sky!?

However the bulk of people posting about this offered a more mundane explanation that it was an example of lens flare as the camera was being pointed towards the sun….but it doesn’t appear to be a particularly sunny day and I am no camera expert but surely you need a sun to cause ‘Lens flare’ The next thing we know it will start being called ‘The Netherlands Swamp gas’

However even though Mr Perton is getting an awful lot of attention for his photo, he still remains very sceptical, believing it is more likely a meteorological light trick.  But how can you explain the unexplainable!?

aaaa


U.I.P SUMMARY

As mentioned above us guys at U.I.P did suggest recently that this object in the sky was not a UFO but in fact had the look or a portal, and now many others are saying the exact same thing too!

You can clearly see that this object is definitely NOT a helicopter as some people have suggested and it is also most definitely not a camera lens flare which has also been mentioned…the fact the you would need the sun to be out to create a lens flare is quite an important fact too in this whole story.

We can obviously at this moment in time a 100% confirm what this is, but lets be honest with ourselves people, the Aliens have to come through somewhere and it has already been admitted by NASA that portals DO in fact exist….which quite possibly makes this photo one of the most famous captures to this date!

Could CERN of opened up a portal to another Dimension….quite possibly considering THIS is what they have confirmed that they are trying to do in their next phase of their project! But surely the risks are unknown of doing such a thing? Yep, and guess what the Scientists clearly have NO backup plan about what to do when they do open up the doors to another Dimension/Universe!?

We will keep you updated on this gripping and intriguing story….It is like the kind of thing we would once of only ever seen in the movies!

U.I.P

Other Dimensions About To Be Discovered?

Other Dimensions About To Be Discovered?

New Cosmic Record Set: Scientists Detect Fastest Neutrino Ever has 1000X Energy of the LHC


Last week, a team from the IceCube Neutrino Observatory, which is located in the southernmost place on Earth (the Geographic South Pole in Antarctica), announced the highest-energy neutrino ever detected. The event occurred and ended in nanoseconds, but it was enough to trip the sensitive detectors at IceCube.

At a gathering this past week in the Netherlands, the team announced that the latest ultra-high-energy neutrino  was a muon neutrino, and its energy levels were simply out of this world.

To clarify, there are three known kinds of neutrinos: Electron neutrinos, muon neutrinos, and tau neutrinos. Ultimately, when muon neutrinos interact, they release a muon. It is this muon that scientists try to detect, and from the data that we gather on it, we can learn about the neutrino that made it.

The energy recorded of this muon was in excess of 2,600 trillion electronvolts (teraelectronvolts, TeV). This breaks the previous record at IceCube, which was set at 2,000 TeV. But where does the neutrino come in? What was its energy?

The team explains, “We have been adding, to our previous analysis, more years of data, and in an extra year we found this spectacular event,” says Francis Halzen, IceCube principle investigator for the University of Wisconsin, Madison. “Utilizing standard model material science, the vitality of this neutrino is some place around 5,000-10,000 TeV, with the in all likelihood esteem some place in the center,” Halzen clarified. “This neutrino packs around 1,000 times the vitality of the LHC shaft. It is terrific.”

Subatomic Neutrino Tracks: Image credit: CERN

In you aren’t aware, neutrinos are subatomic particles with a mass that is close to zero. They are also electrically neutral, and they rarely interact with normal matter. In fact, they are capable of passing through almost all matter without having any sort of interaction with it. They can even pass through entire planets without changing their course.

So then, how were we able to make this detection?

Thousands of sensors are distributed over a cubic kilometer of volume beneath the dense Antarctic ice, and these sensors are set to detect rapid movements of charged leptons (electrons, muons, or taus) that emit Cherenkov radiation. When the particles travel at nearly the speed of light through the ice, they are are detected by the photo multiplier tubes within the digital optical modules that make up the light sensors employed by IceCube.

IceCube aurora neutrino

Ultimately, this structure was created for exactly this purpose: To capture one of the rarest events in the subatomic world—The interaction of a neutrino with matter. And although we didn’t see the neutrino itself, we were able to process the information on it based on what we recorded from the muon as it bumped into an atom. Ultimately, from this data we were able to determine the speed, energy, and source of the neutrino.

Although IceCube, in comparison, detects far fewer neutrinos than traditional telescopes are detecting photons, the ones that are found help give us insight into such things as the cosmic microwave background and other sources of radiation beyond our own galaxy. In many ways, such events open up a whole new world of physics.

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