DEMOCRITUS: I like my system better. My complexity seems simpler than your simplicity. So what are the other five leptons?
LEDERMAN: There are three varieties of neutrinos, plus two leptons called the muon and the tau. But let's not get into that now. The electron is by far the most important lepton in today's global economy.
DEMOCRITUS: So I should worry only about the electron and the six quarks. These explain the birds, the sea, the clouds...
LEDERMAN: In truth, almost everything in the universe today is composed of only two of the quarks—the up and the down—and the electron. The neutrino zings around the universe freely and pops out of our radioactive nuclei, but most of the other quarks and leptons must be manufactured in our laboratories.
DEMOCRITUS: Then why do we need them?
LEDERMAN: That's a good question. We believe this: there are twelve basic particles of matter. Six quarks, six leptons. Only a few exist in abundance today. But they were all here on an equal footing during the Big Bang, the birth of the universe.
DEMOCRITUS: And who believes all this, the six quarks and six leptons? A handful of you? A few renegades? All of you?
LEDERMAN : All of us. At least, all the intelligent particle physicists. But this concept is pretty much accepted by all scientists. They trust us on this one.
DEMOCRITUS: So where do we disagree? I said there was an uncuttable atom. But there were many, many of them. And they combined because they had complementary shape characteristics. You say there are only six or twelve such "a-toms." And they do not have shapes, but they combine because they have complementary electrical charges. Your quarks and leptons are also uncuttable. Now, are you sure there are only twelve?
LEDERMAN: Well ... depends on how you count. There are also six antiquarks and six antileptons and—
DEMOCRITUS: Γρℇατ Zℇυσ∋σ υνδℇρπαντσ [Great Zeus's underpants!]
LEDERMAN: It's not as bad as it sounds. We agree much more than we disagree. But in spite of what you told me, I am still amazed that such a primitive, ignorant heathen could come up with the atom, which we call the quark. What kind of experiments did you do to verify the idea? Here we spend billions of drachmas to test each concept. How did you work so cheaply?
DEMOCRITUS: We did it the old-fashioned way. Not having a Department of Energy or a National Science Foundation, we had to use Pure Reason.
LEDERMAN: So you spun your theories out of whole cloth.
DEMOCRITUS: No, even we ancient Greeks had clues from which we molded our ideas. As I said, we saw that poppy seeds always grow into poppies. The spring always comes after the winter. The sun rises and sets. Empedocles studied water clocks and whirling buckets. One can form conclusions by keeping one's eyes open.
LEDERMAN: "You can observe a lot just by looking," as one of my contemporaries once said.
DEMOCRITUS: Exactly! Who is this sage, so Grecian in his perspective?
LEDERMAN: Yogi Berra.
DEMOCRITUS: One of your greatest philosophers, no doubt.
LEDERMAN: You could say that. But why do you distrust experiment?
DEMOCRITUS: The mind is better than the senses. It contains trueborn knowledge. The second kind of knowledge is bastard knowledge, which comes from the senses—sight, hearing, smell, taste, touch. Think about it. The drink that tastes sweet to you may taste sour to me. A woman who appears beautiful to you is nothing to me. An ugly child appears beautiful to its mother. How can we trust such information?
LEDERMAN: Then you do not think we can measure the object world? Our senses simply manufacture sensory information?
DEMOCRITUS: No, our senses do not create knowledge from the void. Objects shed their atoms. That is how we can see them or smell them—like that loaf of bread I told you about. These atoms/ images enter through our organs of sense, which are passages to the soul. But the images are distorted as they pass through the air, which is why objects very far off may not be seen at all. The senses give no reliable information about reality. Everything is subjective.
LEDERMAN: To you there is no objective reality?
DEMOCRITUS: Oh, there's an objective reality. But we are not able to perceive it accurately. When you are sick, foods taste different. Water might seem warm to one hand and not the other. It is all a matter of the temporary arrangement of the atoms in our bodies and their reaction to the equally temporary combination in the object being sensed. The truth must be deeper than the senses.
LEDERMAN: The object being measured and the measuring instrument—in this case, the body—interact with each other and change the nature of the object, thus obscuring the measurement.
DEMOCRITUS: An awkward way of thinking about it, but yes. What are you getting at?
LEDERMAN: Well, instead of thinking of this as bastard knowledge, one could see it as a matter of uncertainty of measurement, or sensation.
DEMOCRITUS: I can live with that. Or, to quote Heraclitus, "The senses are bad witnesses."
LEDERMAN: Is the mind any better, even though you call it the source of "trueborn" knowledge? The mind, in your world view, is a property of what you call the soul, which in turn is also composed of atoms. Are not these atoms also in constant motion, and interacting with distorted atoms from the exterior? Can one make an absolute separation between sense and thought?
DEMOCRITUS: You make a good point. As I have said in the past, "Poor Mind, it is from us." From the senses. Still, Pure Reason is less misleading than the senses. I remain skeptical of your experiments. I find these huge buildings with all their wires and machines almost laughable.
LEDERMAN: Perhaps they are. But they stand as monuments to the difficulty of trusting what we can see and touch and hear. Your comments about the subjectivity of measurement were, for us, learned slowly in the sixteenth to eighteenth centuries. Little by little we learned to reduce observation and measurement to objective acts like writing numbers in notebooks. We learned to examine a hypothesis, an idea, a process of nature from many angles, in many laboratories by many scientists, until the best approximations to objective reality emerged—by consensus. We made wonderful instruments to help us observe, but we learned to be skeptical about what they revealed until it was repeated in many places by many techniques. Finally, we subjected the conclusions to the test of time. If some young SOB a hundred years later and juicing for a reputation shakes it up, so be it. We rewarded him with praises and prizes. We learned to suppress our envy and fear and to love the bastard.
DEMOCRITUS: But what about authority? Most of what the world learned about my work came from Aristotle. Talk about authority. People were exiled, imprisoned, and buried if they disagreed with old Aristotle. The atom idea barely made it to the Renaissance.
LEDERMAN : It's much better now. Not perfect, but better. Today we can almost define a good scientist by how skeptical he is of the establishment.
DEMOCRITUS: By Zeus, this is good news. What do you pay mature scientists who don't do windows or experiments?
LEDERMAN: Obviously, you're applying for a job as a theorist. I don't hire many of those, though the hours are good. Theorists never schedule meetings on Wednesday because it kills two weekends. Besides, you're not as anti-experiment as you make yourself out to be. Whether you like the idea or not, you did conduct experiments.
DEMOCRITUS: I did?
LEDERMAN: Sure. Your knife. It was a mind experiment, but an experiment nonetheless. By cutting that piece of cheese in your mind over and over again, you reached your theory of the atom.
DEMOCRITUS: Yes, but that was all in the mind. Pure Reason.
LEDERMAN: What if I could show you that knife?
DEMOCRITUS: What are you talking about?
LEDERMAN: What if I could show you a knife that could cut matter forever, until it finally cut off an a-tom.
DEMOCRITUS: You found a knife that can cut off an atom? In this town?
LEDERMAN [nodding]: We're sitting on the main nerve right now.
DEMOCRITUS: This laboratory, it i
s your knife?
LEDERMAN: The particle accelerator. Beneath our feet particles are spiraling through a four-mile-around tube and crashing into each other.
DEMOCRITUS: And this is how you cut away at matter to get down to the a-tom?
LEDERMAN: Quarks and leptons, yes.
DEMOCRITUS: I'm impressed. And you're sure there's nothing smaller?
LEDERMAN: Well, yes; absolutely sure, I think, maybe.
DEMOCRITUS: But not positive. Otherwise you would have stopped cutting.
LEDERMAN: "Cutting" teaches us something about the properties of quarks and leptons even if there aren't little people running around inside them.
DEMOCRITUS: There's one thing I forgot to ask. The quarks—they're all pointlike, dimensionless; they have no real size. So, outside of their electrical charges, how do you tell them apart?
LEDERMAN: They have different masses.
DEMOCRITUS: Some are heavy, some are light?
LEDERMAN: Da.
DEMOCRITUS: I find that puzzling.
LEDERMAN: That they have different masses?
DEMOCRITUS: That they weigh anything at all. My atoms have no weight. Doesn't it bother you that your quarks have mass? Can you explain it?
LEDERMAN: Yes, it bothers us a lot, and no, we can't explain it. But that's what our experiments indicate. It's even worse with the gauge bosons. The sensible theories say that their masses should be zero, nothing, zilch! But...
DEMOCRITUS: Any ignorant Thracian tinker would find himself in the same predicament. You pick up a rock. It feels heavy. You pick up a tuft of wool. It feels light. It follows from living in this world that atoms—quarks, if you will—have different weights. But again, the senses are bad witnesses. Using Pure Reason, I don't see why matter should have any mass at all. Can you explain it? What gives particles their mass?
LEDERMAN: It's a mystery. We're still struggling with this idea. If you stick around the control room until we are into Chapter 8 of this book, we'll clear it all up. We suspect that mass comes from a field.
DEMOCRITUS: A field?
LEDERMAN: Our theoretical physicists call it the Higgs field. It pervades all of space, the apeiron, cluttering up your void, tugging on matter, making it heavy.
DEMOCRITUS: Higgs? Who is Higgs? Why don't you people name something after me—the democriton! By its sound you know it interacts with all other particles.
LEDERMAN: Sorry. Theorists always name things after one another.
DEMOCRITUS: What is this field?
LEDERMAN: The field is represented by a particle we call the Higgs boson.
DEMOCRITUS: A particle! I like this idea already. And you have found this Higgs particle in your accelerators?
LEDERMAN: Well, no.
DEMOCRITUS: So you found it where?
LEDERMAN: We haven't found it yet. It exists only in the collective physicist mind. Kind of like Impure Reason.
DEMOCRITUS: Why do you believe in it?
LEDERMAN: Because it has to exist. The quarks, the leptons, the four known forces—none of these make complete sense unless there is a massive field distorting what we see, skewing our experimental results. By deduction, the Higgs is out there.
DEMOCRITUS: Spoken like a Greek. I like this Higgs field. Well, look, I must go. I've heard that the twenty-first century has a special on sandals. Before I continue on to the future, do you have any ideas about when and where I should go to see some greater progress in the search for my atom?
LEDERMAN: Two times, two different places. First, I suggest you come back here to Batavia in 1995. After that, try Waxahachie, Texas, around, say, 2005.
DEMOCRITUS [snorting]: Oh, come on. You physicists are all alike. You think everything's going to be cleared up in a couple of years. I visited Lord Kelvin in 1900 and Murray Gell-Mann in 1972, and they both assured me that physics had ended; everything was completely understood. They said to come back in six months and all the kinks would be worked out.
LEDERMAN: I'm not saying that.
DEMOCRITUS: I hope not. I've been following this road for twenty-four hundred years. It's not so easy.
LEDERMAN: I know. I say to come back in '95 and 2005 because I think you'll find some interesting events then.
DEMOCRITUS: Such as?
LEDERMAN: There are six quarks, remember? We've found only five of them, the last one here at Fermilab in 1977. We need to find the sixth and final quark—the heaviest quark; we call it the top quark.
DEMOCRITUS: You'll start looking in 1995?
LEDERMAN: We're looking now, as I speak. The whirling particles beneath our feet are being cut apart and examined meticulously in search of this quark. We haven't found it yet. But by 1995 we will have found it ... or proved it doesn't exist.
DEMOCRITUS: You can do that?
LEDERMAN: Yes, our machine is that powerful, that precise. If we find it, then everything is in order. We will have further solidified the idea that the six quarks and six leptons are your a-toms.
DEMOCRITUS: And if you don't...
LEDERMAN: Then everything crumbles. Our theories, our standard model, will be next to worthless. Theorists will be leaping out of second-story windows. They'll be sawing at their wrists with butter knives.
DEMOCRITUS [laughing]: Won't that be fun! You're right. I need to come back to Batavia in 1995.
LEDERMAN: It might spell the end of your theory, too, I might add.
DEMOCRITUS: My ideas have survived a long time, young man. If the a-tom isn't a quark or a lepton, it will turn up as something else. Always has. But tell me. Why 2005? And where is this Waxahachie?
LEDERMAN: In Texas, in the desert, where we're building the largest particle accelerator in history. In fact, it will be the largest scientific tool of any kind built since the great pyramids. (I don't know who designed the pyramids, but my ancestors did all the work!) The Superconducting Super Collider, our new machine, should be in full swing by 2005—give or take a few years, depending on when Congress approves the funding.
DEMOCRITUS: What will your new accelerator find that this one here cannot?
LEDERMAN: The Higgs boson. It will go after the Higgs field. Try to capture the Higgs particle. We hope it will find out for the first time why things are heavy and why the world looks so complicated when you and I know that, deep down, the world is simple.
DEMOCRITUS: Like a Greek temple.
LEDERMAN: Or a shul in the Bronx.
DEMOCRITUS: I must see this new machine. And this particle. The Higgs boson—not a very poetic name.
LEDERMAN: I call it the God Particle.
DEMOCRITUS: Better. Though I prefer a lowercase "g." But tell me: you're an experimenter. What physical evidence have you amassed so far for this Higgs particle?
LEDERMAN: None. Zero. In fact, outside of Pure Reason, the evidence would convince most sensible physicists that the Higgs does not exist.
DEMOCRITUS: Yet you persist.
LEDERMAN: The negative evidence is only preliminary. Besides, we have an expression in this country...
DEMOCRITUS: Yes?
LEDERMAN: "It ain't over till it's over."
DEMOCRITUS: Yogi Berra?
LEDERMAN: Yup.
DEMOCRITUS: A genius.
On the northern rim of the Aegean, in the Greek province of Thrace, the town of Abdera sits at the mouth of the river Nestos. As in many other cities in this part of the world, history is written into the very stones of the hills that overlook the supermarkets, parking lots, and cinemas. Some 2,400 years ago, the town was on the busy land route from the motherland of ancient Greece to the important possessions in Ionia, now the western part of Turkey. Abdera was in fact settled by Ionian refugees fleeing from the armies of Cyrus the Great.
Imagine living in Abdera in the fifth century before Christ. In this land of goatherds, natural events weren't necessarily assigned scientific causes. Lightning strikes were thunderbolts hurled from atop Mount Olympus by an angry Zeus. Whether one enjoyed a calm sea or suffered a ti
dal wave depended on the mercurial moods of Poseidon. Feasts or famines came at the whim of Ceres, the goddess of agriculture, rather than atmospheric conditions. Imagine, then, the focus and integrity of a mind that could ignore the popular beliefs of the age and come up with concepts harmonious with quark and quantum theory. In ancient Greece, as now, progress was an accident of genius—of individuals with vision and creativity. But even for a genius, Democritus was far ahead of his time.
The God Particle Page 8