Physicists at the Fermi National Accelerator Laboratory in Illinois report that they have discovered a new clue that sheds light on one of the biggest mysteries of cosmology: Why the universe is composed of matter and not its opposite, antimatter. If confirmed, the finding portends fundamental discoveries at the new Large Hadron Collider on the border of Switzerland and France. as well as a possible explanation for our own existence.
In a mathematically perfect universe, we would never have existed. According to the basic precepts of Einsteinian relativity and quantum mechanics, equal amounts of matter and antimatter should have been created in the Big Bang and then immediately annihilated each other in a blaze of energy, leaving nothing behind with which to make stars, galaxies and us. And yet the universe as we know it, with its infinite variety, exists, and physicists want to know why.
Sifting data from collisions of protons and antiprotons at Fermilab’s Tevatron, which until last winter was the most powerful particle accelerator in the world, the team, known as the DZero collaboration, found that the fireballs produced pairs of the particles known as muons, which are sort of fat electrons, slightly more often than they produced pairs of anti-muons, according to the New York Times. So the miniature universe inside the accelerator went from being neutral to being about one percent more matter than antimatter.
“This result may provide an important input for explaining the matter dominance in our universe,” Guennadi Borissov, a co-leader of the study from Lancaster University, in England, said in a talk last week at Fermilab in Illinois.
Word spread quickly among physicists. The results have now been posted on the Internet and submitted to science publications.
It was Andrei Sakharov, the Russian dissident and physicist, who first provided a recipe for how matter could prevail over antimatter in the early universe, according to the New York Times. Among his conditions was that there be a slight difference in the properties of particles and antiparticles known technically as CP violation. In effect, when the charges and spins of particles are reversed, they should behave slightly differently. Over the years, physicists have discovered a few examples of CP violation in rare reactions between subatomic particles that tilt slightly in favor of matter over antimatter, but “not enough to explain our existence,” in the words of Gustaaf Brooijmans of Columbia, who is a member of the DZero team.
“The new effect hinges on the behavior of particularly strange particles called neutral B-mesons, which are famous for not being able to make up their minds. They oscillate back and forth trillions of times a second between their regular state and their antimatter state. As it happens, the mesons, created in the proton-antiproton collisions, seem to go from their antimatter state to their matter state more rapidly than they go the other way around, leading to an eventual preponderance of matter over antimatter of about 1 percent, when they decay to muons.”
Whether this is enough to explain our existence is a question that cannot be answered until the cause of the still-mysterious behavior of the B-mesons is directly observed, said Dr. Brooijmans, who called the situation “fairly encouraging.”
The observed preponderance is about 50 times what is predicted by the Standard Model, the assemblage of theories that has ruled particle physics for a generation, meaning that whatever is causing the B-meson to act this way is “new physics” that physicists have been yearning for almost as long.
Dr. Brooijmans said that the most likely explanations were some new particle not predicted by the Standard Model or some new kind of interaction between particles. Luckily, he said, “this is something we should be able to poke at with the Large Hadron Collider.”
Neal Weiner of New York University said, “If this holds up, the Large Hadron Collider is going to be producing some fantastic results.”
Joe Lykken, a theorist at Fermilab, said, “So I would not say that this announcement is the equivalent of seeing the face of God, but it might turn out to be the toe of God.”
