Big Bang Machine
Explore the deepest mysteries of the early universe and the quest to find the Higgs Boson. Airing January 14, 2015 at 9 pm on PBS Aired January 14, 2015 on PBS
On July 4, 2012, scientists at the giant atom smashing facility at CERN announced the discovery of a subatomic particle that seems like a tantalizingly close match to the elusive Higgs Boson, thought to be responsible for giving all the stuff in the universe its mass. Since it was first proposed nearly fifty years ago, the Higgs has been the holy grail of particle physicists: in finding it they validate the “standard model” that underlies all of modern physics and open the door to new discoveries when CERN’s giant collider switches on at higher power in 2015.
Big Bang Machine
PBS Airdate: January 14, 2015
NARRATOR: They built the largest, most complex machine in history, to probe the deepest mysteries of the early universe, as it was at the beginning of time. The Large Hadron Collider is allowing us to see right back to 10-to-the-minus-twelve seconds after the Big Bang.
Within two massive detectors, in conditions harsher even than outer space, tiny particles smash together at nearly the speed of light, unleashing incredible energy.
STEVEN WEINBERG (University of Texas): Trying to figure out what happens in the collisions of two protons at very high energy is like analyzing what happens in the high-speed collision of two garbage trucks.
NARRATOR: Within that spray of debris, physicists search for a tiny bundle of energy, a subatomic particle, proof of an invisible energy field that fills all of space. It just may be the most important feature of our universe. Without it,…
SEAN CARROLL (California Institute of Technology): There are no atoms, there are no molecules, there's no chemistry, there's no life.
NARRATOR: Fifty years of effort, 10-billion dollars and thousands of researchers around the world: for them the stakes have never been higher.
LYN EVANS (CERN): It's practically my whole professional life that's led to this point.
NARRATOR: It's the moment of truth, when science flips the switch on the Big Bang Machine, right now, on NOVA.
In Europe, a stunning announcement: one of the world's most wanted fugitives has finally been captured.
ROLF-DIETER HEUER (CERN 2009-2015): Done!
NARRATOR: The announcement came at the end of a high-speed, high-stakes chase.
FABIOLA GIANOTTI (CERN/ATLAS Experiment): …a mystery.
DON LINCOLN (Fermi National Accelerator Laboratory): Three-hundred people were hot on the trail.
ADAM DAVISON (University College London): Decades worth of work...
NARRATOR: It was a truly international effort that drew to its dramatic conclusion, here…
ROLF-DIETER HEUER: It's a historic milestone today…
NARRATOR: …on the border of France and Switzerland, 300 feet below ground.
But this wasn't a search for some outlaw or criminal mastermind. It was a hunt for something far more elusive, an unstable bundle of energy, far smaller than an atom, that winks out of existence in a trillion-trillionth of a second.
It's evidence of a force that fills all of space, completely invisible, and yet without it, life, Earth, the universe we know could not exist.
Finding this elusive particle marks the end of a quest that required constructing the largest, most complex machine the world has ever seen, a quest that consumed nearly half a century, billions of dollars and asked thousands of scientists, across the globe, to invest years, even decades of their careers, with no guarantee of success.
LHC SCIENTIST: I got a job to do this in 1993. It's my eleventh year now.
JON BUTTERWORTH (University College London): About 10 years, me.
ADAM DAVISON: Yeah, and about five years for me.
FABIOLA GIANOTTI: …twenty years, something like that.
DON LINCOLN: Since 1994, I guess.
LYN EVANS: It's practically my whole professional life that's led to this point.
NARRATOR: The discovery has been hailed as one of the greatest scientific victories of all time and has already won the Nobel Prize.
SEAN CARROLL: It's an enormous triumph.
JOE LYKKEN (Fermi National Accelerator Laboratory): This was my generation's Manhattan Project, and I wanted to be on the inside, looking out. It's been extremely exciting.
NARRATOR: But what is this mysterious quarry? What does it actually do? And why was finding it so important?
That story begins at the very beginning of time, when the universe came into being, in a massive explosion, called the “Big Bang.”
JON BUTTERWORTH: So, here we have the Big Bang,…
NARRATOR: Billions of years ago,…
JON BUTTERWORTH: …—deserves a little bit of color, I think—and then the timeline of the universe. This is where we are, this, now, the age of the universe like 13.7-billion years after the Big Bang. And so, working backwards, we know that we had the dinosaurs, so here's a dinosaur; then life itself, first D.N.A., at about four-billion years ago.
NARRATOR: Before D.N.A., there was the earth; before that, the first stars; before them, just atoms. While atoms were once thought to consist of just three basic particles—neutrons, protons and electrons—physicists now know some of these are made of even more fundamental stuff, the basic building blocks of our universe.
JON BUTTERWORTH: The big question, then, is where did those building blocks come from? The answer to all that lies in the first second.
NARRATOR: In the first instant of existence, when the universe was unimaginably hot, the cosmos was filled with identical bundles of energy, moving at the speed of light, all indistinguishable from one another, but then something changed.
Distinct types of particles emerged, with different properties, like electric charge and mass, what we experience as weight. Now we live in a universe full of tangible stuff, and while that monumental shift from nothing to something must have happened almost immediately, how it happened was one of the biggest unanswered questions in physics.
JON BUTTERWORTH: The mysteries of existence lie within this second. Certainly we understand the science, we understand the physics. Look backwards into this second, but at some point we just want that knowledge. And the Large Hadron Collider is allowing us to see right back to 10-to-the-minus-12 seconds after the Big Bang. Beyond that, there be dragons or dinosaurs.
NARRATOR: The Large Hadron Collider is a massive particle accelerator—the largest machine in the world—designed to simulate the universe, as it was a trillionth of a second after the Big Bang. To solve the mystery of mass, it smashes protons together at energy so high that it is capable of testing an idea first suggested in 1964 by several scientists around the world, including a young theoretical physicist named Peter Higgs. His mathematics suggested that right after the Big Bang, an invisible energy field was somehow switched on and now fills the entire universe.
Just the way that a magnetic field effects some materials, but not others, he suggested that this new field selectively effects some fundamental particles, causing some of them to take on mass. Very massive particles, like the quarks that make up protons and neutrons, interact strongly with this field. Electrons, which form the outer shells of atoms, interact less strongly and are very lightweight. And still others, like photons, particles of light, have no mass, because they don't interact with the field at all.
The theory implied that a universe without a Higgs field might not be a very friendly place. And that got people's attention.
LISA RANDALL (Harvard University): If there were no Higgs mechanism, elementary particles wouldn't have mass.
SEAN CARROLL: If electrons didn't have mass, that means they would move at the speed of light; and if electrons move at the speed of light, electrons do not settle down into atoms; and if electrons are not settled down into atoms, there are no atoms, there are no molecules, there's no chemistry, there's no life.
LISA RANDALL: …nothing, it would look nothing like what we see today.
STEVEN WEINBERG: We wouldn't be here. And there would be no physicist to ask these questions.
NARRATOR: When Higgs submitted his theory to a journal, the editors, based at CERN, rejected it.
PETER HIGGS (University of Edinburgh): My reaction was that they clearly hadn't understood what I was saying.
NARRATOR: Undeterred, he revised the paper, adding a paragraph saying, in effect, that if the field exists, we should find evidence of it in the form of a particle that would turn up in an accelerator. In other words, if you smash particles together energetically, you'll make a ripple in the field. And if you apply enough energy, you just might be able to detect it in the form of a particle.
The second time around, an American journal published the paper, and Peter Higgs got a lot of credit. But in reality, the idea was cooked up independently by a bunch of scientists: Philip Anderson, Robert Brout, Francois Englert, Gerry Guralnik, Carl R. Hagen, Peter Higgs, Tom Kibble and Gerard ‘t Hooft. Some have suggested that it really should be called this, but since that's impossible to pronounce, it's simply called the “Higgs field.”
Gradually, the theory gained support, but without the evidence of a particle, now called the Higgs boson, it remained unproven.
DON LINCOLN: To be honest, we weren't sure that the Higgs existed.
JOE LYKKEN: Mr. Higgs and his collaborators were saying that there was an invisible energy field everywhere in the universe. So, the “invisible” sounds a little odd, and the “everywhere in the universe” also sounds kind of farfetched. So, that was a lot for people to swallow.
JOE INCANDELA (CERN/CMS Experiment): There are many people who thought this can't be the answer. I've heard people describe it as a trick. It was just a mathematical trick to make the equations work out.
NARRATOR: Finding something that's all around us is surprisingly tricky, because the Higgs boson doesn't actually exist, at least not in any form that we can easily detect.
So, in 1998, scientists from around the world came together at CERN, the Center for European Nuclear Research located on the border of France and Switzerland, to build a particle accelerator that would have enough power to create such a profound disturbance in the Higgs field that the predicted Higgs bosons would pop into existence and present themselves.
But easier said, than done.
FABIOLA GIANOTTI: In order to find this particle, we had to build this complex, cutting-edge accelerator.
JOE INCANDELA: The work is the work of thousands of people, 20 years of effort that went into building these detectors.
FABIOLA GIANOTTI: …twenty years of efforts of the international community.
NARRATOR: From dozens of nations, with the U.S. contributing 500-million dollars, it took 10-billion dollars and 10 years to complete the Large Hadron Collider, a massive masterpiece of engineering, to find one of the tiniest pieces of the cosmos.
MELISSA FRANKLIN (Harvard University/ ATLAS Experiment): It's a very cool and expensive eye that can look at very, very small distances, like a billionth of a billionth of a meter.
LYN EVANS (CERN): We designed this machine, so that wherever the Higgs boson would be, we would be able to find it.
NARRATOR: Flushing the Higgs out of hiding begins in a modest little red bottle, full of hydrogen atoms, the smallest and most abundant element in the universe.
MICK STORR (CERN): All the protons that we use at CERN are taken from a bottle of that size. They start their journey here, and they continue down this orange line, and that is the linear accelerator.
NARRATOR: Trillions of hydrogen atoms, stripped of their electrons, are injected into the collider.
MICK STORR: Every 1.2 seconds, 10-to-the-power-14 protons are being accelerated down that line.
NARRATOR: The protons accelerate around larger and larger loops, until they are finally directed into the main ring.
To keep the increasingly energetic particles confined, the LHC relies on immensely powerful magnetic fields, generated by 1,232 primary superconducting magnets, cooled to just a few degrees above absolute zero by 120 tons of liquid helium.
After about 20 minutes of acceleration, each bunch of protons is moving at nearly the speed of light, with as much energy as an onrushing locomotive.
Finally, the protons are carefully steered into violent head-on collisions, converting the huge energy into showers of exotic, energetic particles, scattering in all directions, many decaying into showers of even more particles, setting the stage for the hard work of detecting the Higgs.
STEVEN WEINBERG: Trying to figure out what happens in the collisions of two protons at very high energy, like you have in the Large Hadron Collider, is like analyzing what happens in the high-speed collision of two garbage trucks. Garbage is spread all over everything. And most of it is garbage, in the sense that it's not interesting. It's old stuff that we already knew about. And in all this garbage, that's spraying out in all directions on the highway, you have to find the golden needle, the rare artifact that you're looking for: the Higgs boson, something entirely new.
NARRATOR: To the scientists at CERN, a collection of physicists from all over the world, the stuff produced in those powerful collisions is anything but garbage. Each particle has a well-understood identity, described with great precision in one of the most accurate theories ever devised to explain the workings of the universe.
It's called the Standard Model, and one of its key contributors is Frank Wilczek.
DR. FRANK WILCZEK (Massachusetts Institute of Technology): Hi. Welcome. Come on in. A lot of what I do is really just play. I mean, I play with the equations and ideas.
NARRATOR: All that playing won Frank a Nobel Prize for his contribution to the Standard Model.
FRANK WILCZEK: Well, what have we got here? It looks like an instrument of torture for the mind.
NARRATOR: The Standard Model is essentially an understanding of how all the known pieces of the universe fit together—except for the mechanism of gravity—creating a mind-boggling tapestry.
FRANK WILCZEK: This is going to be a hell of a puzzle to figure out. All right now, a promising start. Now, we think the Standard Model contains all you need, in principle, to describe how molecules behave, all of chemistry, how stars work, all of astrophysics, not only how things behave but what can exist. These are the rules of the game.
The ingredients of the Standard Model are of three basic sorts. There's what you might, broadly, call “matter,”—that's sort of lumps of stuff that have a certain degree of permanence—and these are, on the one hand, quarks. They include the building blocks of protons and neutrons and atomic nuclei. And leptons—most prominent lepton in everyday life is certainly the electron. So those are matter particles. On the other side, we have what you might call “force particles” or “force mediators.”
NARRATOR: Called “bosons,” some of these particles are more like lumps of energy. They transmit the forces that bring the matter particles to life. They include the photon, which carries the electromagnetic force; the gluons, that carry the strong force, which holds protons and neutrons together; and W and Z bosons that are responsible for the weak force governing radioactivity.
With just this small list of ingredients, the Standard Model explains the physical properties of the elementary building blocks of nature.
SEAN CARROLL: The Standard Model is just a handful of particles and forces, and it explains every experiment ever done, by every human being in the history of science. So, it's quite impressive in what it's managed to do.
DON LINCOLN: It explains how stars burn; it explains how radioactivity occurs; it explains how chemistry works; it explains how light works. It's an amazing theory.
NARRATOR: The first particles were discovered in experiments and became the foundation for the Standard Model. But then the theorists took over, and all of the particles discovered in the last 40 years were first predicted by the mathematics of the Standard Model, and then found experimentally. The Higgs boson, a force particle, was the last and most challenging piece of the puzzle. That's why finding it was such an obsession among theorists and experimentalists, alike.
In September, 2008, with much fanfare, the giant accelerator was switched on. The LHC was ready to go to work. It was an exciting time, full of high expectations.
LYN EVANS: Designing and building this machine, it's just incredible to see it come to life.
NARRATOR: But then, just nine days after start-up, disaster struck.
LYN EVANS: It was 11 o'clock in the morning, and I got a call to come over, something looks serious. And when I got over there, I had never seen such carnage.
NARRATOR: A short circuit burned a hole in a giant container of liquid helium used to cool the magnets. Six tons of helium was released into the tunnel, and more than 50 of the giant magnets were fried. The 10-billion-dollar LHC was dead in the water.
Undaunted, engineers worked to repair the machine, and physicists continued to refine the computer programs that would analyze the vast amount of data that the LHC would produce, once it was running at full power.
LHC SCIENTIST: “3, 2, 1…”
NARRATOR: By late 2009, after 14 months of repair work and reengineering, the LHC was more robust than ever, and finally ready to begin the hunt in earnest.
Now, protons are whizzing both ways around the ring at nearly the speed of light. At the center of the two Higgs detectors, the beams cross inside ATLAS—a massive machine the size of a cathedral—and also within its smaller cousin, CMS. Even though the beams are microscopically small, the vast majority of particles contained in them whiz past each other without incident.
MELISSA FRANKLIN: When you collide 100-billion protons and 100-billion protons, most of the protons are just seeing each other and going, “Hello,” and going on.
NARRATOR: But about 800-million times every second, pairs of protons meet head-on.
MELISSA FRANKLIN: What's called a “hard collision,” when the proton breaks up, so it's no longer a proton. That's an interesting collision and that happens only about 20 times, out of all these billions of protons crossing.
NARRATOR: In each of these powerful collisions, dozens of new particles flash into existence and spray outward, their unique signatures tracked by the huge detectors capturing the action, 40-million times a second, incredibly fast, but still not able to spot the Higgs directly.
SEAN CARROLL: The Higgs is actually kind of a difficult particle to find. It's kind of subtle in how you look for it. As soon as you create it, it decays very, very quickly. The lifetime of the Higgs is about one zeptosecond, which is like 10-to-the-minues-21seconds. So, in fact, you'll never even see it in a particle accelerator. It doesn't move that…far enough for you to see any track left behind.
NARRATOR: And so, the only way to detect the Higgs would be by spotting the more familiar particles that the quickly vanishing Higgs decays into. The math predicted about a dozen different possible “decay modes,” as they're called. But the relative likelihood of any of them depended on the mass of the Higgs, which was a total mystery. It must have seemed like a cosmic joke on the theorists.
JOE LYKKEN: The irony, if you like, is that, although the Higgs Field that's related to the Higgs boson gives other particles mass, the one property of the Higgs boson that was not predicted by professor Higgs and his colleagues was the mass of the Higgs boson itself. So, its mass could have been anything from very, very light, by our standards, to very, very heavy.
NARRATOR: Since the Higgs could theoretically decay in so many different ways, the Higgs hunters had to be willing to sift through all of the collision debris, looking for slight increases in the number of detectable particles, with very specific characteristics, into which the Higgs could possibly decay.
SEAN CARROLL: So, it's not like looking for a needle in a haystack, when at least you know that you found a needle. It's like looking for hay in a haystack. You're looking for a little bit more hay with certain properties then certain other properties.
NARRATOR: That daunting challenge meant building enormously complicated detectors to track and count every bit of debris coming out of those collisions.
MELISSA FRANKLIN: And then we have to somehow, with all of the particles that come out of this event, we have to reconstruct them and find if there are new particles or new processes that are happening.
NARRATOR: The mathematics predicts that the Higgs should often decay into particles that are also maddeningly hard to detect, like quarks, the particles that make up protons and neutrons in the nuclei of atoms.
LISA RANDALL: They looked in every possible way you can look. In the end, they looked for the Higgs boson decaying into photons.
NARRATOR: Out of every thousand Higgs bosons created, a few should decay in a way that produces a pair of photons, light particles which can be measured very precisely in the detectors.
By knowing the energy and angle between pairs of photons, scientists can tell if they were likely produced by a Higgs. And by looking for unexpectedly high concentrations of certain photons, over billions of collisions, scientists hoped to zero in on the Higgs and, as a consequence, pinpoint its exact mass, the one missing value in the theory. It proved to be a statistical sifting process of dizzying complexity.
Luckily, they had a head start. Years of experiments in other colliders had ruled out many possible masses for the Higgs, measured in units called gigaelectronvolts, or GeV.
ADAM DAVISON: So, on this line of what the mass of the Higgs might be, we can draw on what previous experiments have, have tried, and where they've been able to exclude it from being.
NARRATOR: A less powerful accelerator, the LEP Collider at CERN, a predecessor of the LHC, had already ruled out the Higgs being at the bottom end of potential masses.
ADAM DAVISON: In fact, they were able to say that the mass of the Higgs is, with 95 percent confidence, 114 GeV or more. So, after LEP, the next major milestone in the, in the Higgs search was limits set by another collider, in the U.S., called the Tevatron. The Tevatron was able to exclude a range here, around 160 GeV, here.
NARRATOR: In 2011, CERN moved that upper boundary still lower.
ADAM DAVISON: The LHC has been able to rule out a big region, from 145 quite far up.
NARRATOR: But this last remaining energy range was also the trickiest to search. It's the area in which the unique signature of the Higgs would most be deeply buried under the background noise of other particles created in the collider.
EXPERIMENTAL SCIENTISTS: If I was to bet, I would probably put it at 130 GeV.
Probably somewhere around 120 GeV.
Somewhere between 120 and 130 GeV.
One hundred fourteen GeV, because it's the most difficult place to look, and we haven't found it yet.
Ah, that's a good question, because, you know, you are assuming that the Higgs actually exists, which I'm, I'm starting to believe it probably does not exist.
NARRATOR: As data piled up at the LHC, scientists narrowed the range even further. It seemed that they were either about to close in on the Higgs particle or prove that it didn't exist at all.
SEAN CARROLL: People were beginning to worry a little bit that we hadn't found the Higgs yet and maybe weren't going to find it. And that would've been a complete shock, because we know that something is doing the job of the Higgs.
JOE LYKKEN: You start to get a little nervous, because either it's there, or there isn't a Higgs boson at all.
NARRATOR: By the end of 2011, the window narrowed even further.
ADAM DAVISON: LHC, with the new data from the whole of 2011, is able to expand the area that it can exclude the Higgs from.
NARRATOR: The new lower limit had risen to 115 GeV, and the new upper limit dropped to 127 GeV. And within that range, interesting things were showing up in the data.
ADAM DAVISON: So, the really exciting thing was that the reason the LHC experiments weren't able to exclude anything inside this remaining window is that, in fact, they see an excess of events, the early signs of the Higgs boson, if it's there.
NARRATOR: An excess of events means that the LHC was producing more particles of interest, in particular, pairs of photons.
LISA RANDALL: So, what you're looking for, it's called a bump, because, at that particular energy, you should see a lot more decays, or a lot more events than you would expect if the Higgs boson wasn't there. If you see a bump, that's a clue that something's going on.
NARRATOR: Those excess photon pairs were showing up in not just one, but in both detectors, and at practically the same mass. CMS was seeing a spike in the number of photons, which could be the signal of a Higgs with a mass of 124 GeV and Atlas was seeing a similar spike near 125.
Now, with the hunt finally closing in, the LHC continued smashing protons, sorting through the debris and piling up the data for another six months.
FABIOLA GIANOTTI: We saw a signal growing, growing, every week, every day.
NARRATOR: Until, at last, on July 4, 2012, the heads of ATLAS and CMS, Fabiola Gianotti and Joe Incandela called a meeting.
ROLF-DIETER HEUER: Two presentations from the two experiments, ATLAS and CMS.
NARRATOR: There to hear the news firsthand, Peter Higgs himself. It was standing room only.
ROLF-DIETER HEUER: Good afternoon, everybody in Melbourne.
NARRATOR: But it was also beamed live around the world.
MELISSA FRANKLIN: So, of course, everyone's heard lots of rumors, at this point, within the collaborations. But there are these two collaborations, the CMS collaboration and the ATLAS collaboration, and we aren't supposed to know what they have. And I didn't. You know, you'd heard stories, but I hadn't seen their data. So that's kind of exciting.
DIETER HEUER: So, today is a special day on a search for a certain particle.
NARRATOR: But no one was quite prepared for the short, definitive announcement that was to come.
DIETER HEUER: And I ask Joe Incandela from CMS to take the floor.
NARRATOR: This was about to become one of the defining moments in the history of physics and science.
JOE INCANDELA: And the energy was so incredible. It was like a big party, almost. I mean, people were really excited. And it was just then, I think, I started to really appreciate where we were and that this was a major discovery. I put the slide up, and before I can say anything, there was a gasp across the whole audience. Now a major result like this from one experiment could still be wrong.
ROLF-DIETER HEUER: Now, we go immediately to ATLAS' Fabiola Gianotti, please.
FABIOLA GIANOTTI: Thank you.
JOE INCANDELA: But Fabiola brought the same confidence for her results.
FABIOLA GIANOTTI: You can already see, here, the compatibility between what we observed: one big spike, here in this region, here.
MELISSA FRANKLIN: If you look at these plots that were shown, first thing you want to see is did CMS and ATLAS find the bump in the same place?
NARRATOR: And in fact they had.
FABIOLA GIANOTTI: …an excess at a mass of 126.5 GeV.
NARRATOR: Both teams had found an excess of photons pointing to the same mass.
MELISSA FRANKLIN: And that was pretty convincing. So, you're going, like, “Wow, we rock!”
ROLF-DIETER HEUER: As a layman, I would now say, “I think we have it. You agree?”
NARRATOR: The LHC had found the Higgs particle.
ROLF-DIETER HEUER: We have observed a new particle, consistent with a Higgs boson.
JOE INCANDELA: It's like running a marathon. Suddenly, you realize you crossed the finish line.
ROLF-DIETER HEUER: Maybe another round of applause to all the guys who took part in the project for more than 25 years.
LYN EVANS: Well, it comes as a big surprise to me, I must say. I went into that seminar expecting, I mean, a good result, but I was gobsmacked, as they say.
NARRATOR: The hunt that spanned half a century was over.
DON LINCOLN: The Higgs boson hid for 50 years. But, you know, like they said with the Canadian Mounties, “ They'll get their man.” It could run, but it couldn't hide forever.
NARRATOR: It appeared Higgs and his colleagues had been right. The mystery of how particles gain mass had been solved. The last piece of the Standard Model had been found.
PETER HIGGS: For me, it's really an incredible thing that it's happened in my lifetime.
FABIOLA GIANOTTI: I, I had the pleasure to, to meet Peter Higgs at the end of the seminar and, uh, exchange a hug. He told me, “Congratulations to you and your experiment for this incredible achievement.” And of course, I replied, “Congratulations to you! You are the first person to be congratulated.”
PETER HIGGS: I think it's not appropriate for me to answer any detailed questions, at this stage. This is an occasion celebrating an experimental achievement, and I simply congratulate the people involved.
NARRATOR: Ironically, the achievement took place at the very same institute where, nearly 50 years earlier, an editor had rejected Higgs' initial paper.
In a fitting end to the saga, Peter Higgs and Belgian Physicist Francois Englert, who had independently come up with the idea for the Higgs field, won the 2013 Nobel Prize. Englert's colleague, Robert Brout, certainly would have been honored as well, had he lived to see the day.
So why is all this important? Why does proving the existence of the Higgs field matter?
Building an enormous Big Bang machine to recreate conditions in the universe near the beginning of time and completing the Standard Model is a tremendous scientific achievement.
MELISSA FRANKLIN: Finding the Higgs, sheds light on all of particle physics and cosmology. It's all connected. All our models of how the universe began, how it expanded, everything is affected by the Higgs field and by how we understand the universe.
NARRATOR: Perhaps discovering the Higgs boson and the field it proves will open new doors,…
FABIOLA GIANOTTI: The discovery of the Higgs is just the first step. In science, you make a step forward, you answer a question, but then other questions open up.
NARRATOR: …into even greater mysteries that still remain, beyond the Standard Model.
JOE INCANDELA: The Standard Model can't be the final thing. There is something beyond the Standard Model; we know that. Hopefully, the Higgs can be of some guidance in that direction.
LISA RANDALL: Yes, we do know the Standard Model works. It works incredibly well. But it…we know it's not the whole story. And anytime, in the history of physics, where people thought they had the whole story, they were wrong. And so, we're looking for what is the next piece, not just in terms of one particle, but in terms of forces, in terms of understanding nature.
DON LINCOLN: The number of mysteries in the Standard Model is huge, which is fine because, as a scientist, I'm drawn to mysteries.
NARRATOR: One mystery that the Standard Model can't answer is perhaps the most fundamental of them all: Why isn't our universe empty? Because according to the mathematics behind the Standard Model, it should be.
MICHIO KAKU (City College of New York): Science has given us a set of laws that describe the world so accurately that we can predict the motions of a coin tossed in the air, because we understand the law of gravity. We understand electro-magnetism so well that we can use our G.P.S. satellites to locate your car to within a few inches. And we understand the nuclear force so well that we can predict the future evolution of the sun, itself.
NARRATOR: Those mathematical equations that work so well to describe the laws of the physical world are bound together by something that we see around us every day, something that characterizes our faces and the natural world, even the tiniest structures, like viruses and our D.N.A.: symmetry.
FRANK WILCZEK: In the Standard Model, symmetry rules. The laws are dictated, really, in their form, by requiring tremendous amounts of symmetry. That's how we found them.
NARRATOR: The equations of the Standard Model seem to predict a universe in perfect balance, formless and without structure, as it was at the very beginning. And if it had remained that way, nothing would exist.
MICHIO KAKU: If the laws of science are framed at their most perfect, most symmetrical form, then life cannot exist at all. There'd be no mountains, rivers, valleys, no D.N.A., no people, nothing.
NARRATOR: A universe created along absolutely symmetric principles would be in perfect balance. The Higgs field is the first clue to what broke the symmetry of that completely uniform early universe.
MICHIO KAKU: The state of perfect symmetry is very similar to the state of perfect balance. Think of a spinning top. It exists in a state of perfect symmetry. No matter how you rotate, everything looks the same.
NARRATOR: Even more so than the symmetry of a spinning top, at this instant of creation, every place in the universe would have been symmetrical, identical, to every other place. But perfection isn't stable.
MICHIO KAKU: The slightest imperfection, the slightest little defect, will cause it to vibrate, perturb and fall to a lower energy state. Symmetry has been broken.
NARRATOR: Within a fraction of a second of the Big Bang, physicists believe, the absolute symmetry of the universe was shattered by a tiny fluctuation. The Higgs field appeared in all of space. The forces split apart, the particles of the Standard Model became distinct, structure emerged. This fall from perfection was what allowed us to come into being.
MICHIO KAKU: Everything we see around us is nothing but fragments of this original perfection. Whenever you see a beautiful snowflake, a beautiful crystal or even the symmetry of stars in the universe, that's a fragment. That's a piece of the original symmetry at the beginning of time.
NARRATOR: Finding and studying the Higgs is a vital first step in the quest to understand that early state, when, all of the particles that make up what we can perceive came into being, as well as a much greater quantity of mysterious stuff that we know is out there, but that we can't directly detect, called “dark matter.” What are these missing pieces? When James Gates came to study at M.I.T., he was determined to unlock the secrets of the early universe and understand what happened to the unity that was once there.
S. JAMES GATES, JR. (University of Maryland): The universe and we are intricately tied together. This idea of unity turns out to be one of the most powerful driving themes in physics, and it keeps getting us to look for deeper and deeper connections. So, ultimately, perhaps we exist because the universe had no other choice.
NARRATOR: He looked at the Standard Model, the matter particles and the bosons, the force particles, that hold everything together. He wondered if these two groups of particles that seem so different are related in some profound and hidden way.
This question, “Why is there this fundamental asymmetry of forces and matter?” led him to a powerful mathematical theory called “supersymmetry.”
JAMES GATES: It was the asking of this what-if question that drove the construction of supersymmetry, which had an incredible resonance for me, when I was a graduate student. I saw one more beautiful balance that we could put in nature.
NARRATOR: One of the pioneers of supersymmetry, Jim Gates saw, in the mathematics, a possible hidden world of new particles no one had suspected.
JAMES GATES: Mathematics leads us to find things we didn't know were there before. Supersymmetry is an example of that. We know about ordinary matter, the mass leads you on to discover super matter and super energy.
NARRATOR: The theory gives every matter particle a force partner and every force particle a matter partner. These heavier supersymmetric twins are labeled “sparticles.”
JAMES GATES: So, once you believe this math that says there's more to existence, then you have to wonder what these other things are. So, you have to name them, at a very, you know, at the very first step. So, in nature there is a thing called the electron. The math says it has a super partner called the selectron; muon, it'd have to be a smuon; photon, there'd have to be a photino; quark, there'd have to be squarks; Z particle, there'd have to be zino; the W particle, there'd have to be a wino; and that's how supersymmetry works.
NARRATOR: According to supersymmetry, matter and forces aren't so distinct after all. There's a grand symmetry between them, but we can currently see only one partner from each pair. However strange it seems, this theory has gained widespread support from theoretical physicists, not just for the beauty of its equations, but for what it might help explain.
JAMES GATES: When supersymmetry began as a topic of discussion, no one realized what it can do. It turns out that studying the mathematics, we get a firm foundation for the existence of everything.
NARRATOR: Supersymmetry could shed light on dark matter—the missing particles that aren't included in the Standard Model—and even help to explain how symmetry was broken in the first place.
FRANK WILCZEK: I very much want supersymmetry, because it's a beautiful thing, by any standard and would take our understanding of nature to a new level. So I want that.
NARRATOR: Finding the Higgs pushed the LHC to the limit of what it could do. So, a few months after the Higgs announcement, the scientists at CERN shut down the giant collider and began a planned two-year upgrade. As it begins its second act, it will smash protons even more energetically.
MELISSA FRANKLIN: So, when the LHC turns back on, in 2015, we will be at twice the energy we were before.
NARRATOR: The increased power will help physicists to study the Higgs with more precision, but the real hope is that they will find something entirely new.
MELISSA FRANKLIN: Every single experimentalist is only thinking this: “Is there a massive particle we can now make with this energy, with these energetic protons, that we haven't seen before?”
NARRATOR: For the theorists too, it is an exciting and nerve-wracking time.
JAMES GATES: If we find supersymmetry in experiments, for me, personally, it will mean that I have not wasted my entire research career, because this is the one question, as a young scientist, I decided had my name on it to study.
FRANK WILCZEK: I'm starting to get nervous, you know? So, there were a lot of people who predicted that supersymmetry was just around the corner, or something else, that as soon as LHC turned on, they'd see spectacular effects on the one hand, or that the Higgs particle would be heavy on the other hand. Those are all wrong. Now it's make or break time.
NARRATOR: For the thousands of scientists who have come together in this great quest, pushing the frontiers of knowledge has been a wild, rollercoaster ride. And with the Large Hadron Collider, the fun has only just begun.
Megan E. Chao
Daniel H. Birman
James W. O'Keeffe
J. Adam Fenster
University of Rochester
University of Edinburgh
ITP, Goethe University, Frankfurt
NASA/University of Chicago and Adler Planetarium and Astronomy Museum
New York City Police Department
Produced for NOVA by the NOVA Science Unit for WGBH Boston.
© 2012 BBC for Hunt for the Higgs
Big Bang Machine Additional Material © 2015 WGBH Educational Foundation
All rights reserved
This program was produced by WGBH, which is solely responsible for its content.
- Image credit: (LHC, Cern)
- © Christophe Vander Eecken/Corbis
- Jon Butterworth
- University College London
- Sean Carroll
- California Institute of Technology
- Adam Davison
- University College London
- Lyn Evans
- Melissa Franklin
- Harvard University/ATLAS Experiment
- S. James Gates, Jr.
- University of Maryland
- Fabiola Gianotti
- CERN/ATLAS Experiment
- Peter Higgs
- University Edinburgh
- Joe Incandela
- CERN/CMS Experiment
- Michio Kaku
- City College of New York
- Don Lincoln
- Joseph Lykken
- Lisa Randall
- Harvard University
- Mick Storr
- Steven Weinberg
- University of Texas at Austin
- Frank Wilczek
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