December 20, 2016

New CERN experiment could solve the mysteries of antimatter

Antimatter has been notoriously difficult to produce, capture, and maintain, but scientists at the European Organization for Nuclear Research (CERN) have reportedly developed a new way to observe and analyze these elusive materials – a project two decades in the making.

As BBC News explains, most scientists believe that the Big Bang produced equal amounts of both matter and antimatter, but for reasons not completely understood, the universe currently is made up almost exclusively of matter. Existing theories have been unable to explain why, but a team of CERN researchers has apparently come one step closer to finding the answer.

In research published Monday in the journal Nature, members of CERN’s ALPHA collaboration reported the first ever measurement of an antimatter atom on the optical spectrum – a feat which they accomplished by trapping the antimatter atoms, then shining a laser on them to see whether or not they behaved any differently than regular atoms.

“Using a laser to observe a transition in antihydrogen and comparing it to hydrogen to see if they obey the same laws of physics has always been a key goal of antimatter research,” ALPHA team spokesperson Jeffrey Hangst said in a statement. This breakthrough, he and his colleagues added, could result in the dawning of “a completely new era in high-precision antimatter research.”

So far, so good for the Standard Model, researchers say

One of the primary reasons that antimatter has been so difficult to work with, BBC News said, is that it get annihilated if it comes into contact with ordinary matter. However, by using a specially designed magnetic trap, the ALPHA collaboration was able to capture an antihydrogen atom.

The goal, Hangst told the British media outlet, was to see if antimatter obeyed the same laws of physics as ordinary matter – specifically, the Standard Model that explains each of the subatomic particles and the interactions between them. By recording measurements of the optical spectrum of the captured antihydrogen atom, the CERN researchers have confirmed that such particles do indeed behave in a manner consistent with the Standard Model, said Yahoo! News.

“Within experimental limits, the result shows no difference compared to the equivalent spectral line in hydrogen. This is consistent with the Standard Model of particle physics, the theory that best describes particles and the forces at work between them, which predicts that hydrogen and antihydrogen should have identical spectroscopic characteristics,” CERN explained.

As Nature noted, the findings are good news for scientists who have spent decades working to find a way to study how antimatter absorbs and emits light. The hope, the journal added, is that this could be the first step towards a test of charge-parity-time or CPT symmetry, one of the key symmetries of the known laws of physics. Based on CPT symmetry predictions, antimatter and matter should have the same energy levels, as was the case in the ALPHA team’s experiments.

“We've tried to shine the same ‘color’ of light, if you will, on an antihydrogen atom that we would use for hydrogen, to see if it responds in the same way. The answer so far is yes,” Hangst told BBC News. “What really matters here and for the future is how precisely you do that measurement. Right now, we have a precision of a few parts in 10 billion. We hope to get much, much better than that – the precision with hydrogen is a few parts in a thousand trillion.”


Image credit: CERN