Force That Binds Antimatter Together Measured For The First Time

As we know, antimatter is the opposite of normal matter and it consists of elementary particles which are the antiparticles (antiprotons, antineutrons, and positrons) of those making up normal matter.

Based on our general interpretation that the sub-atomic particles of antimatter have properties opposite to those of normal matter, we assume that force that binds antimatter particles together would be something opposite to the force that binds regular matter together. Surprisingly, physicists at Rice University have found that the attractive force between antiprotons is similar to that between protons. Not only that, but also they have managed to measure it for the first time.

The result of the study was published in the journal Nature. For the study, the team created antiprotons by smashing gold ions together and then they managed to measured two important parameters : the scattering length and the effective range of interaction between two antiprotons. Once they were done with the measurements, they were able to understand the attractive force holds together the nuclei in antimatter and how this compares to regular matter.

“This is about the subtle difference in the way matter and antimatter interact with each other,” said Rice physicist Frank Geurts, in the university news release.

The results of their experiment showed that the attractive forces between the antiparticles are not actually that different at all. “It could have been that antimatter didn’t have the same attractive force as matter and would have helped explain how these differences, during the initial part of the Big Bang, might have resulted in antimatter not having survived in the shape of stars and planets, as matter did,” Geurts said.

“That’s where this research is helpful. The interactions between two antimatter particles turn out to be quite similar to matter particles. It may not give us a solution to the bigger problem, but we most definitely removed one option,” he said.

For antiprotons, the scattering length was around 7.41 femtometers, and the effective range was 2.14 femtometers, which is nearly equivalent to their proton counterparts.

[1 fm = 1.0 x 10^-15 m | For reference, visit Femtometer – Wikipedia]

“This discovery isn’t a surprise,” said Xin, whose Ph.D. thesis focuses on rather exotic systems called muonic atoms.

“We’ve been studying the interaction between nucleons (particles that make up an atom’s nucleus) for decades, and we’ve always thought the forces between antimatter particles are the same as for matter. But this is the first time we’ve been able to quantify it.”

Now that we know a little more about the universe, the study has indeed ruled out some leading hypotheses regarding the characteristics of antimatter. It certainly has changed physicists’ viewpoint on the existing imbalance nature between matter and antimatter because both happen to obey the same law of attraction.

[Hat Tip: Rice University, Nature – Measurement of Interaction Between Antiprotons | Image: Brookhaven National Laboratory]