Scientists Blast Antimatter Atoms With a Laser For The First Time (npr.org)

For the first time, researchers from Indiana University were able to blast antimatter atoms with a laser to measure the light emitted from the anti-atoms. The researchers hope to answer one of the big mysteries of our universe: Why, in the early universe, did antimatter lose out to regular old matter? NPR reports: "The first time I heard about antimatter was on Star Trek, when I was a kid," says Jeffrey Hangst, a physicist at Aarhus University in Denmark. "I was intrigued by what it was and then kind of shocked to learn that it was a real thing in physics." He founded a research group called ALPHA at CERN, Europe's premier particle physics laboratory near Geneva, that is devoted to studying antimatter. That's a tricky thing to do because antimatter isn't like the regular matter you see around you every day. At the subatomic level, antimatter is pretty much the complete opposite -- instead of having a negative charge, for example, its electrons have a positive charge. And whenever antimatter comes into contact with regular matter, they both disappear in a flash of light. In the journal Nature, his team reports that they've now used the special laser to probe this antimatter. So far, what they see is that their anti-hydrogen atoms respond to the laser in the same way that regular hydrogen does. That's what the various theories out there would predict -- still, Hangst says, it's important to check. "We're kind of really overjoyed to finally be able to say we have done this," he says. "For us, it's a really big deal." From the journal Nature: "Researchers at CERN, the European particle physics laboratory outside Geneva, trained an ultraviolet laser on antihydrogen, the antimatter counterpart of hydrogen. They measured the frequency of light needed to jolt a positron -- an antielectron -- from its lowest energy level to the next level up, and found no discrepancy with the corresponding energy transition in ordinary hydrogen."

Comments

Why lasers?

[jmv]

Anyone with better physics knowledge can comment here? Why would you use lasers to measure differences between matter and anti-matter? As far as I know, the only difference between the two is supposed to involve the weak force rather than the electromagnetic force (on which light is based). Considering that these guys aren't idiots, I must be missing something. How are the lasers useful?

Re:Why lasers?

[Dorianny]

The C and P symmetries violations in weak interactions is not enough to explain why there is No detectable antimatter in the Universe. Scientists are performing experiments that they should know the results of in the hopes that it gives unexpected result. Ernest Rutherford's landmark experiment with gold foil and alpha particles is just one of many experiments yielding unexpected results, invalidating the wildly accepted Plumb Pudding theory of the atom and opening the door to Quantum Mechanics. The discovery of the expansion of the universe and later its acceleration were both unexpected results. Sometimes it pay to check if the sky is actually blue (which ironically only appears to humans as blue because of a quirk of our vision system. If human (or to alien) eyes were equally sensitive to all wavelengths the sky might look violet or ultra-violet)