The apparent discovery of the Higgs boson was hailed as a historic milestone, but for particle physicists it mainly marks the beginning of a new search. Rival teams at CERN in Switzerland are trying to decipher the secrets of antimatter. If they succeed, the laws of physics will have to be rewritten … //
… Whatever Happened to Antimatter?
One of the central puzzles that could pave the way into this new territory lies in the question that Jeffrey Hangst has chosen to pursue: Why does the world consist of matter? And what happened to antimatter?
Hangst is particularly interested in an unusual material. It behaves just like ordinary matter, and yet it’s completely different. The properties are the same, meaning that anti-glass would splinter like glass, anti-gold would shine like gold and anti-water would splash like water. And there would also be no visible difference between a person made of normal matter and a person made of antimatter. They would be completely identical.
But heaven forbid that both — matter and antimatter, image and copy — come into contact with one another. If that happened, there would be a bright flash of light and suddenly both would have disappeared.
The most important thing, however, is the fact that antimatter doesn’t actually exist on a sustained basis. The anti-world is nothing more than a possibility, one that nature has apparently not made into a reality. In the theorists’ equations both the world and the anti-world play equal roles. But in the real, observable universe, everything consists of matter, not antimatter.
“Understanding why this is the case has always fascinated me,” says Hangst. Physicists are convinced that properly understanding the relationship between matter and antimatter would be tantamount to a revolution in comprehending the universe.
Something Instead of Nothing:
Back in the mid-19th century, German philosopher Friedrich Wilhelm Schelling came up with what he called the “final, desperation-filled question”: Why is there anything at all? Why is there not nothing? In modern physics, Schelling’s metaphysical astonishment has been rephrased: Why don’t matter and antimatter exist in equal parts in the universe?
Physicists agree that the force of the Big Bang created both forms of existence in equal amounts. With each particle, its counterpart, the corresponding antiparticle, was born. And because nature gave both the capacity to destroy one another, the moment of their creation already included the seeds of their demise.
But then some providential change must have fundamentally altered the course of the universe. Physicists would love to understand what exactly happened shortly after the Big Bang. At this point, they only know the results of those events early in the history of the cosmos: They led to matter gaining the upper hand over antimatter.
But by no means was it by a large margin. On the contrary, the ratio that once existed between the two types of particles can be calculated using the density of particles in today’s universe. The result is astonishing: There were 1,000,000,001 particles to 1,000,000,000 antiparticles. Can such a miniscule imbalance be significant?
Yes, it can. The subsequent evolution of the universe would reveal that this one particle was critical. If matter and antimatter had been exactly equal, cosmic existence would have destroyed itself within fractions of a second, leaving nothing behind but a monotonous desert of radiation.
Tiny Imbalance: … //
… Massive Search:
But now the big search for answers has begun, a search that involves the use of technology on a massive scale:
- At the Brookhaven National Laboratory outside New York City, scientists are smashing together gold ions at nearly the speed of light. Last year, they managed to identify 18 anti-helium nuclei, the largest antiparticles detected to date, in the inferno of many billions of particle fragments.
- In a bid to detect even larger particles of antimatter, particle physicists have set up experimental apparatus in space. Their detector, which is docked to the International Space Station (ISS), has been listening for signals from the anti-world since May of last year.
- In Japan, scientists are bombarding a tank filled with 50,000 tons of highly purified water with neutrinos. Their goal is to detect tiny differences in the properties of neutrinos and their antiparticles, anti-neutrinos.
- One of the four massive underground detectors at the LHC at CERN is devoted primarily to one task: detecting differences in the behavior of matter and antimatter.
Part 3: Searching for Antimatter in Space.
Link: CERN Director on Finding Higgs: The Real Work Has only Just Begun.