Tag: Standard Model

Why Does the Higgs Particle Matter?

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source: Big Questions Online

author: Frank Wilczek

Editors’ Note: It has been one year since scientists announced the discovery of a particle believed to be Higgs.  Read this essay by a Nobel prize winner in physics and share your comments on ourFacebook page.

Imagine a planet encrusted with ice, beneath which a vast ocean lies. (Imagine Europa.)

Within that ocean a species of brilliant fish evolved. Those fish were so intelligent that they took up physics, and formulated the laws that govern motion. At first they derived quite complicated laws, because the motion of bodies within water is complicated.

One day, however, a genius among fish, call her Fish Newton, had a startling new idea. She proposed fundamental laws of motion––Newton’s laws––that are simpler and more beautiful than the laws the fish had derived directly from experience. She demonstrated mathematically that you could reproduce the observed motions from the new, simpler laws, if you assume that there is a space-filling medium that complicates things. She called it Ocean.

Of course our fish had been immersed in Ocean for eons, but without knowing it. Since it was ever-present, they took it for granted. They regarded it as an aspect of space itself––as mere emptiness. But Fish Newton invited them to consider that they might be immersed in a material medium.

Thus inspired, fish scientists set out to find the atoms of Fish Newton’s hypothetical medium. And soon they did!

That story is our own. We humans, like those fish, have been living within a material medium for millennia, without being consciously aware of it.

The first inkling of its existence came in the 1960s. By that time physicists had devised especially beautiful equations for describing elementary particles with zero mass. Nature likes those equations, too. The photons responsible for electromagnetism, the gravitons responsible for gravity, and the color gluons responsible for the strong force are all zero mass particles. Electromagnetism, gravity, and the strong force are three of the four fundamental interactions known to physics. The other is the weak force.

A problem arose, however, for the W and Z bosons, which are responsible for the weak force. Though they have many properties in common with photons and color gluons, Wand Z bosons have non-zero mass. So it appeared that one could not use the beautiful equations for zero mass particles to describe them.  The situation grew desperate: The equations for particles with the properties of W and Z, when forced to accommodate non-zero mass, led to mathematical inconsistencies.  

The right kind of cosmic medium could rescue the situation, however. Such a medium could slow down the motion of W and Z particles, and make them appear to have non-zero mass, even though their fundamental mass––that is, the mass they would exhibit in ideally empty space––is zero. Using that idea, theorists built a wonderfully successful account of all the phenomena of the weak interaction, fully worthy to stand beside our successful theories of the electromagnetic, strong, and gravitational interactions. Our laws of fundamental physics reached a qualitatively new level of completeness and economy.

The predictions of those “medium-based” laws got tested with the sharpest precision and in the most extreme conditions that experimenters could devise. They were eager to disprove them.  The Swedish Academy of Sciences gives prizes for things like that!  But the laws passed every test, with flying colors. This grand synthesis has been so successful, for so long, that it has become known as the Standard Model.  

Of course, the success of the Standard Model gave circumstantial evidence for the cosmic medium it relies on. Nevertheless, until a few months ago a nagging question remained: What is that cosmic medium made from? No known particles had the right properties.

On July 4, 2012, scientists at the CERN laboratory, near Geneva, announced the discovery of a new particle that seemed as though it might have the required properties. Over the last few months, more detailed measurements have confirmed and sharpened the initial discovery.  Several tough consistency checks came in positive. In March CERN declared victory.  The main building block of our cosmic Ocean, the Higgs particle, has been successfully identified.

Why does it matter? 

The discovery of the Higgs particle is, first and foremost, a ringing affirmation of fundamental harmony between Mind and Matter.  Mind, in the form of human thought, was able to predict the existence of a qualitatively new form of Matter before ever having encountered it, based on esthetic preference for beautiful equations.

We plumb the depth of that Mind-Matter harmony if we meditate on the challenge the Higgs particle discovery posed.

The Higgs particle is heavy, couples poorly to matter, and is extremely unstable.  (Its lifetime is much too short to be measured directly, but is inferred to be roughly 10-22sec.)   To produce it, scientists had to plan, and then build, the Large Hadron Collider, or LHC. That machine is an extraordinary feat of engineering.  The main ring, which houses counter-circulating beams of extremely energetic protons, is 27 kilometers around. The protons are moving at very nearly the speed of light, so they make the circuit about 10,000 times per second.  Their paths must be controlled very accurately, using powerful, precisely machined, superconducting magnets. Superconductivity requires low temperatures, so the ring is held at just 2 degrees above absolute zero. Even intergalactic space, filled with the 2.7 degree microwave background, is hotter than that. Thus the LHC ring is the coldest extended region in the universe, unless of course some extraterrestrial civilization is doing similar tricks.

The proton beams are made to cross at a few points, where collisions can occur. The collisions are violent encounters. They reproduce densities of energy achieved when the universe was a mere microsecond old, close to the Big Bang. They make Little Bangs, from which hundreds of energetic particles emerge. Less than one collision per billion contains a Higgs particle.  And those that do, don’t come labeled “Higgs particle here!” Far from it.  As I mentioned previously, the Higgs particle is extremely unstable.  One sees only the products of its decay.  From those remnants––which, remember, are delivered mixed up with lots of other debris––one must reconstruct what happened well enough to identify the Higgs.  Related QuestionsDoes Quantum Physics Make it Easier to Believe in God?Is Information the Basis of Reality?

From this description, I hope you’ll get the (correct) impression that the discovery of the Higgs particle built upon, and required, a tremendous foundation of prior knowledge. We relied on our mathematical equations to guide us in building the machine and to anticipate, in quantitative detail, 99.9999999 percent of what would happen when it ran, so we could concentrate on the interesting novelties.  Our equations proved up to the task! This is profound testimony that Mind, in its mathematical productions, accurately reflects the system Matter lives by.

Confirmation of the idea that we live in a cosmic medium has two other, more specific philosophical consequences, as well.

We have learned that some of the observed peculiarities of elementary particles can be blamed on the cosmic medium they inhabit. We can work creatively with beautiful equations that seem to be––and that, taken literally, actually are–– “too good for this world” by imagining a simpler, emptier world where they hold, and devolving from there to here.  Can we take that strategy further?  Might most––or all?––of the apparent differences among elementary particles be due to the complicating influence of other cosmic media, made from heavier and more elusive Higgs-like particles?

Physicists have taken up that imaginative opportunity, with gusto. We can construct specific, attractive models whose basic equations obliterate the distinctions among strong, weak, and electromagnetic forces.  These unified theories go well beyond the Standard Model. They predict the existence of new particles and forces, which could well be discovered within a few years, after the LHC is upgraded to run at higher energies. They are credible, because they also predict quantitative relationships among the observed forces that agree with existing measurements. Specifically, they predict the relative strengths of the strong, weak, and electromagnetic interactions, which are free parameters with the Standard Model itself.  In this way, Einstein’s vague dreams of unification have begun to take on tangible, quantitative form.

The other implication is cosmological. Given that we live in a material medium, it is natural to ask whether that medium might change with time, or might have different properties elsewhere — just as our standard analogue, water, can boil into steam, or freeze into ice. Indeed, calculations show that the Higgs-particle medium that fills our universe today could not persist at arbitrarily high temperatures. It is like a liquid that “boils away.” Then the W and Z bosons lose their masses, and the operative laws of physics look different! That almost certainly occurred, during the earliest moments of the Big Bang.

Cosmologists have taken up these imaginative opportunities, also with gusto. Although the cosmic phase transition associated with the (now) known Higgs-particle medium was probably tame, other transitions of that sort could have had dramatic consequences. In particular, they might trigger periods of extremely rapid expansion––cosmic inflation. That has proved to be an extremely fruitful idea in early-universe cosmology.

Space-filling media with variable properties also encourage speculations that the laws of physics might operate quite differently in different locations. There is presently no direct evidence for any effect of that kind, but an inhomogeneous Multiverse is a logical possibility that no longer seems entirely fanciful.

In conclusion, coming back to Earth, I’d like to mention an aspect of the discovery I can only describe as moral.  The scientific work leading to the Higgs particle discovery involved thousands of engineers and physicists, not to mention billions of taxpayers, from all over the world co-operating to pursue a common goal. For most of the highly gifted participants, it involved long, often frustrating and sometimes tedious labor, with modest prospects for personal reward. They did it, anyway, because they wanted to understand the world better, and to be part of something great. They did, and they were. In this we have seen, I think, an example of humanity at its best.

Discussion Questions:

Can you imagine some works of art, or events, that would add to our appreciation of these discoveries?   Music?  Multimedia? Performances?  Installations?

What does the beauty of the fundamental laws––which everyone who understands them senses––mean?   Is it a lucky accident, a trick of perception, or something deeper?

Do the achievements of CERN, and of the scientific research enterprise in general, provide a model for creative human cooperation that we can build on, to address other, more immediate problems?
Emphasis Mine

See: https://www.bigquestionsonline.com/content/why-does-higgs-particle-matter?utm_medium=email&utm_source=editor&utm_campaign=higgs%20re-post%207-2

 

The Higgs Boson Hangover

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From: Slate

By: Lawrence Krauss

“On July 4, the physics community responded with jubilation to an announcement that had been anticipated for 50 years: the discovery of the Higgs Boson. Just as half of the country was ecstatic in 2008 when Barack Obama was first elected—supposedly heralding the end of “business as usual” in Washington—the Higgs breakthrough appeared to herald a new era in particle physics, one that could bring us closer to a possible unified theory describing all of the fundamental forces of nature.

Unfortunately, in both cases, reality has intervened. Obama discovered that being elected and governing a divided and partisan country are two different things. In physics, too, we are uncomfortably close to what many of us would consider the nightmare scenario. The initial buzz of the Higgs discovery has faded, and now we face a monstrous hangover: What happens next?

Briefly, the Higgs is an elementary particle predicted 50 years ago during the development of the standard model of particle physics. The standard model beautifully describes three of the four fundamental forces in nature and is one of the most remarkable theoretical constructions in the history of science. Specifically, the Higgs was predicted in order to provide a natural mechanism to explain what now appears to be an amazing cosmic accident: the fact that some particles have mass and others don’t. (For a thorough explanation, listen to my conversation with Blogging Heads’ Robert Wright.)

Before the Large Hadron Collider at CERN in Switzerland was turned on, there were five possibilities for what might be revealed: 1) No Higgs and nothing else, 2) a Higgs with unexpected properties and nothing else, 3) lots of other stuff but no Higgs, 4) a Higgs and lots of other stuff, and 5) a single Higgs with the properties predicted in the standard model.

Many might imagine that physicists were rooting for door No. 5 because we like to be vindicated. In fact, nothing could be further from the truth. The discovery of the Higgs validates the prediction of the standard model, and with that much of the theoretical underpinning of modern fundamental physics and cosmology. But now we are completely baffled about the origins of the standard model itself. I, for one, was rooting for no Higgs at all, because that would have meant our fundamental ideas were on the wrong track. Nothing can be more exciting than finding that we have to start from scratch and discover a whole new reality hidden.

While the Higgs discovery was announced in July, the announcement was based on preliminary data. In Kyoto in November, the LHC teams reported on six more months’ worth of data, giving us more clues as to what we really have on our hands. If the LHC reveals the a standard model Higgs and nothing else—that is what we have seen in the data reported in Kyoto—we will confront some major problems. That would mean we have no empirical clues as to what theoretical ideas we should next explore in hopes of answering long-standing questions, including perhaps what caused the Big Bang itself. We won’t know where to focus next. Will the next great discovery be just around the corner, to be made at a successor machine in Geneva or elsewhere? Or do we have to build an implausibly large accelerator perhaps the size of the solar system?

It was hard enough to convince the governments of the world to spend money pushing the edges of knowledge even when we had a pretty good idea what we were looking for, as was the case with the Higgs. In the current world, with shrinking budgets for everything (except maybe weapons and debt repayments), it is hard to imagine any government willing to fund the next generation of research when the outcome may be only that we need to work harder still and pay yet more money to uncover the secrets of the universe.

Indeed, because of the unfortunate way in which we fund big science projects in this country, it is almost impossible to preserve funding for long-term, large-scale projects that are relatively esoteric. For example, the Superconducting Supercollider, which was being built in Texas in the 1980s and early ’90s and which would have been a much grander and more powerful machine than the LHC, was killed, even though it had been approved by three consecutive presidents in their budgets.

One is virtually guaranteed to have some kind of economic recession every decade or two, and if a grand science endeavor takes that long to complete, it is easy pickings for a Congress intent on cutting budgets without offending constituencies with influential lobbyists. Scientists, you may be surprised to learn, are not power players in Washington. We don’t vote as a block, and in economic hard times, it is pretty challenging to convince people to fund projects that don’t promise direct technological spinoffs but rather might answer fundamental questions about the universe. Over much of the last decade in this country, the funding of particle physics, for example, has not even kept up with inflation. This, in spite of the fact that perhaps one-half of the current U.S. GDP might be due to investments in curiosity-driven fundamental research a generation or two ago.

It is too early to settle on a tale of doom and gloom, just as it is not yet time to give up on the hope of Obama changing the status quo in Washington. The LHC will run for several more years, and there is still a good chance that it will uncover new clues that can guide us. But fortune favors the prepared mind, and that sometimes means preparing for the worst.

This article arises from Future Tense, a collaboration among Arizona State University, the New America Foundation, and Slate. Future Tense explores the ways emerging technologies affect society, policy, and culture. To read more, visit the Future Tense blog and the Future Tense home page. You can also follow us on Twitter.

emphasis mine

see: http://www.slate.com/articles/technology/future_tense/2013/01/the_higgs_boson_was_found_now_what.html

The discovery of the Higgs boson particle puts our understanding of nature on a new firm footing

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From: Slate

By:  Lawrence Krauss

“Who would have believed it? Every now and then theoretical speculation anticipates experimental observation in physics. It doesn’t happen often, in spite of the romantic notion of theorists sitting in their rooms alone at night thinking great thoughts. Nature usually surprises us. But today, two separate experiments at the Large Hadron Collider of the European Center for Nuclear Research (CERN) in Geneva reported convincing evidence for the long sought-after “Higgs” particle, first proposed to exist almost 50 years ago and at the heart of the “standard model” of elementary particle physics—the theoretical formalism that describes three of the four known forces in nature, and which to date agrees with every experimental observation done to date.

The LHC is the most complex (and largest) machine that humans have ever built, requiring thousands of physicists from dozens of countries, working full time for a decade to build and operate. And even with 26 kilometers of tunnel, accelerating two streams of protons in opposite directions at more than 99.9999 percent the speed of light and smashing them together in spectacular collisions billions of times each second, producing hundreds of particles in each collision; two detectors the size of office buildings to measure the particles; and a bank of more than 3,000 computers analyzing the events in real time in order to search for something interesting, the Higgs particle itself never directly appears.

Like the proverbial Cheshire cat, the Higgs instead leaves only a smile, by which I mean it decays into other particles that can be directly observed. After a lot of work and computer time, one can follow all the observed particles backward and determine the mass and other properties of the invisible Higgs candidates. Like the proverbial Cheshire cat, the Higgs instead leaves only a smile, by which I mean it decays into other particles that can be directly observed. After a lot of work and computer time, one can follow all the observed particles backward and determine the mass and other properties of the invisible Higgs candidates.

I say candidates, because so far each of the two major LHC experimental collaborations has claimed to discover a new particle with properties consistent with the other, and consistent with the general predictions of the standard model, which suggests that the Higgs particle should be produced at a rate comparable to the rate observed and should decay into the specific combinations of known elementary particles that are observed. They are being very conservative. One can in fact quantify the likelihood that the observations are mistaken and that the events are actually background noise mimicking a real signal. Each experiment quotes a likelihood of very close to “5 sigma,” meaning the likelihood that the events were produced by chance is less than one in 3.5 million. Yet in spite of this, the only claim that has been made so far is that the new particle is real and “Higgs-like.” The existing data set is still too small to statistically determine with precise accuracy that the data is consistent with the standard model.

This cautious approach is actually a good thing, because it leaves open the possibility that the particle being observed is not exactly the simple Higgs particle of the standard model. Instead, it may point the way toward understanding whatever new physics underlies the standard model—and perhaps explain outstanding mysteries from the question of why the universe is made of matter and not antimatter, to whether our universe is unique.

The idea of the Higgs particle was proposed nearly 50 years ago. (Incidentally, it has never been called the “God particle” by the physics community. That moniker has been picked up by the media, and I hope it goes away.) It was discussed almost as a curiosity, to get around some inconsistencies between predictions and theory at the time in particle physics, that if an otherwise invisible background field exists permeating empty space throughout the universe, then elementary particles can interact with this field. Even if they initially have no mass, they will encounter resistance to their motion through their interactions with this field, and they will slow down. They will then act like they have mass. It is like trying to push your car off the road if it has run out of gas. You and a friend can roll it along as long as it is on the road, but once it goes off and the wheels encounter mud, you and a whole gang of friends who may have been sitting in the back seat cannot get it moving. The car acts heavier.

Within a few years, it had been recognized that this phenomenon could not only explain why elementary particles like the particles that make up our bodies have the masses they do, but it could also illuminate why two of the four known forces in nature, electromagnetism and the so-called “weak” force (responsible for the processes that power the sun), which on the surface appear very different at the scales we measure, are actually at a fundamental scale merely different manifestations of a single force, now called the “electro-weak” force.

 All of the predictions based on these ideas have turned out to be in accord with experiment. But there was one major thing missing: What about the invisible field? How could we tell if it really exists? It turns out that in particle physics, for every field in nature, like the electromagnetic field, there must exist an elementary particle that can be produced if one has sufficient energy to create it. So, the background field, known as a Higgs field, must be associated with a Higgs particle.

In the 1990s in the United States, a gigantic machine called the Superconducting Super Collider was being built (involving the largest tunnel ever dug—some 60 miles in circumference) to search for the Higgs—and the origin of mass. But Congress, in its infinite wisdom (Congress seems to have gotten no wiser since), decided that the country couldn’t afford the $5 billion to $10 billion that had already been approved by three different presidents. Back then, $5 billion was a lot of money! So, the LHC was constructed in Geneva by a group of European countries, and the rest is history, or will be.

The discovery announced today in Geneva represents a quantum leap (literally) in our understanding of nature at its fundamental scale, and the culmination of a half-century of dedicated work by tens of thousands of scientists using technology that has been invented for the task, and it should be celebrated on these accounts alone.

But I find it particularly exciting for two reasons—one scientific, the other more personal. First, the standard model, as remarkably successful as it has been, leaves open more questions than it answers. What causes the Higgs field to exist throughout space today? Are there other forces that dynamically determine its configuration? Why doesn’t the same phenomenon that causes the Higgs particle to exist at the mass it does cause gravity and the other forces in nature to behave similarly? Over the past 40 years or so, a host of theoretical speculations have been developed to answer these questions. But like those who are sensorially deprived, we may just be hallucinating. The cold water of experiment may now wash away many of our wrong ideas and, perhaps more importantly, could point us in the right direction. In the process I expect what we will discover about the universe may currently be beyond our wildest dreams.

More than this, however, the Higgs field implies that otherwise seemingly empty space is much richer and weirder than we could have imagined even a century ago, and in fact that we cannot understand our own existence without understanding “emptiness” better. Readers of mine will know that as a physicist, I have been particularly interested in “nothing” in all of its forms and its relation to something—namely us. The discovery of the Higgs says that “nothing” is getting ever more interesting.

Emphasis Mine

see:http://www.slate.com/articles/technology/future_tense/2012/07/higgs_boson_announcement_from_cern_why_the_god_particle_is_so_important_.single.html

What’s a Higgs Boson among friends.

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By Robert Evans

GENEVA (Reuters) – Scientists chasing a particle they believe may have played a vital role in creation of the universe indicated Monday they were coming to accept it might not exist after all.

But they stressed that if the so-called Higgs boson turns out to have been a mirage, the way would be open for advances into territory dubbed “new physics” to try to answer one of the great mysteries of the cosmos.

The CERN research centre, whose giant Large Hadron Collider (LHC) has been the focus of the search, said it had reported to a conference in Mumbai that possible signs of the Higgs noted last month were now seen as less significant.

A number of scientists from the centre went on to make comments that raised the possibility that the mystery particle might not exist.

“Whatever the final verdict on Higgs, we are now living in very exciting times for all involved in the quest for new physics,” Guido Tonelli, from one of the two LHC detectors chasing the Higgs, said as the new observations were announced.

CERN’s statement said new results, which updated findings that caused excitement at another scientific gathering in Grenoble last month, “show that the elusive Higgs particle, if it exists, is running out of places to hide.”

NEW PHYSICS

The centre’s research director Sergio Bertolucci told the conference, at the Indian city’s Tata Institute of Fundamental Research, that if the Higgs did not exist “its absence will point the way to new physics.”

Under what is known as the Standard Model of physics, the boson, which was named after British physicist Peter Higgs, is posited as having been the agent that gave mass and energy to matter just after the Big Bang 13.7 billion years ago.

As a result, flying debris from that primeval explosion could come together as stars, planets and galaxies.

In the subterranean LHC, which began operating at the end of March 2010, CERN engineers and physicists have created billions of miniature versions of the Big Bang by smashing particles together at just a fraction under the speed of light.

The results of those collisions are monitored by hundreds of physicists not just at CERN but in linked laboratories around the world which sift through the vast volumes of information generated by the LHC.

Scientists at the U.S. Fermilab near Chicago have been in a parallel search in their Tevatron collider for nearly 30 years. Last month they said they hoped to establish if the Higgs exists by the end of September, when the Tevatron closes down.

For some scientists, the Higgs remains the simplest explanation of how matter got mass. It remains unclear what could replace it as an explanation. “We know something is missing, we simply don’t quite know what this new something might be,” wrote CERN blogger Pauline Gagnon.

“There are many models out there; we simply need to be nudged in the right direction,” added Gagnon, an experimental physicist.

(Editing by Andrew Heavens)

From http://af.reuters.com/article/worldNews/idAFTRE77L5L420110822?pageNumber=2&virtualBrandChannel=0&sp=true

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