Physicists observe the light spectrum of antimatter for the first time

After two decades of experiments, scientists working at CERN‘s ALPHA experiment have finally visualized the light spectrum emitted by antimatter, fulfilling a long-standing goal of particle research.

Measuring the antihydrogen spectrum with high-precision offers an extraordinary new tool to test whether matter behaves differently from antimatter and thus to further test the robustness of the Standard Model (Image: Maximilien Brice/CERN)

“This represents a historic point in the decades-long efforts to create antimatter and compare its properties to those of matter,” theoretical physicist Alan Kostelecky from Indiana University, who was not involved in the study, told NPR.

“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,” said Jeffrey Hangst, Spokesperson of the ALPHA collaboration.

Antimatter is a strange thing. It is a material composed of anti-particles with the same mass as ordinary particles but opposite charges, lepton numbers, and baryon numbers (leptons and baryons are subatomic particles). As the name puts it, they are similar but exactly opposite to regular matter. A mirror reflection, so to speak. We know antimatter exists, we’ve seen it in the lab, but why the universe is filled with matter and virtually completely devoid of antimatter is anyone’s guess. The fact that antimatter is so hard and expensive to produce in a lab makes it even harder to study this mystery – and yet, modern particle theory predicts that every single particle in the universe has its own opposite antiparticle. This is one of the biggest unsolved problems in physics.

Antimatter spectrum

Atoms consist of electrons orbiting around a nucleus. When the electrons move, they emit and absorb light at different frequencies, representing the atom’s spectrum. Every element has its own unique spectrum, through which it could be identified, and the study of these spectra (called spectroscopy) has numerous applications in chemistry, physics, and astronomy. But what about antimatter?

The Antihydrogen Laser Physics Apparatus, or ALPHA experiment at CERN captured 14 or so antihydrogen atoms per trial and blasted them with a laser to see what kind of light they absorb. ALPHA is a unique experiment at CERN, able to produce antihydrogen atoms and hold them in a specially-designed magnetic trap, manipulating antiatoms a few at a time. Trapping antihydrogen atoms allows them to be studied using lasers or other radiation sources.

“Moving and trapping antiprotons or positrons is easy because they are charged particles,” said Hangst. “But when you combine the two you get neutral antihydrogen, which is far more difficult to trap, so we have designed a very special magnetic trap that relies on the fact that antihydrogen is a little bit magnetic.”

As expected (and hoped), the spectrum of anti-hydrogen was identical to that of hydrogen.

“It’s long been thought that antimatter is an exact reflection of matter, and we are gathering evidence to show that is indeed true,” Tim Tharp from ALPHA told Ryan F. Mandelbaum at Gizmodo.

I say “hoped” because if the spectra didn’t turn out to be identical, then it would mean that much of what we hold as true today – including the Big Bang theory and Einstein’s special relativity – wouldn’t hold up. Special relativity assumes that a single unified thing called spacetime splits differently into space and time for observers moving relative to each other. The spectra were identical, which means that the theory of relativity passed yet another difficult test. But researchers are already planning to create more antimatter and blast it with a different type of laser, to observe even more spectra.

Particle physics is a bizarre and complicated world and we are only now getting the chance to test theories proposed many decades ago.The fact that these theories are holding op, that researchers got so many things right only through theory is a testament to the brilliant mind which contributed to this field of science.


7 thoughts on “Physicists observe the light spectrum of antimatter for the first time

  1. Xinhang Shen

    Einstein's relativity has already been disproved both theoretically and experimentally (see “Challenge to the special theory of relativity” March 1, 2016 Physics Essays). The most obvious evidence disproving special relativity is the absolute time shown by the universally synchronized clocks on the GPS satellites which move at high velocities relative to each other while special relativity claims that time is relative (i.e. the time on each reference frame is different) and can never be synchronized on clocks moving with relative velocities. We should abandon the wrong relativity theory as well as all other relativistic spacetime based physics theories to open our mind in the search of new theories. As suggested on the paper, aether can be easily detected with the modified Fizeau experiment, and the clocks on the GPS satellites to find the velocities relative to aether because Hefele-Keating experiment has shown that the velocity relative to aether will influence the frequency of atomic clocks.

    As this is such a critical message that can prevent billions of taxpayer's dollars from being wasted on the wrong physics theories, I and all other people, especially science news reporters, are obliged to deliver this message to the entire community of the physicists in the world.

  2. Bruce Voigt

    CERN experiments, Billions. MY experiments, next to nothing. Blow on …your hand, the air will be cool. THERMAL Have you noticed our spring and summer to have been cold? Oh I don’t mean temperature wise, it’s been a balmy seasonal, “ask anyone” nice year. No I mean cold, cold, like when the weather man say’s it’s a balmy 22 degrease and your chilling in the breeze. Well you really are, and I’ll try and explain it this way. — Man discovered that temperature interacted with mercury and the thermometer was born, I know, I know this is not making sense but hang in there. The house is hot as heck so you have a fan cooling a room. Coming from the hot bathroom it’s refreshing to get back to your cooled room. The thermometer taken from the bathroom reads 40 degrees and now in the cooled room reads 38 degrees. Next day (hot as heck) the bathroom reads a hot 38 and the comfortable room with fan reads 36. Ok now this is my discovery. — The fan in the room is causing a reaction that has air cells chipping, in other words that one cell that produces cold from its poles is now producing cold from the co zillion poles of it’s chips. Because Forces of Equal Evolution act Upon Forces of Equal Evolution the cold producing chips or molecules of air do not interact with the mercury of your thermometer. This explains the mystery of wind chill.

  3. Brian

    This is cool science. I tried a little background research and it's very divergent. Does antimatter move backward in time? Can uncharged particles like photons have anti version? Since they got a spectrum, I think that proves photons do not annihilate when they contact antimatter. Are there anti photons?

  4. Xinhang Shen

    They just wrongly interpreted the corrections of the clocks on the GPS satellites. Do you know that all the clocks on the GPS satellites after the corrections are precisely synchronized i.e. all showing the same absolute time? This universal synchronization has already disproved special relativity which claims that clocks can never be synchronized on clocks with relative velocities.

  5. Xinhang Shen

    No, the clocks are in different frames as satellites are moving with huge relative velocities, but they are all synchronized relative to each other and the ground clocks.

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