Scientists report first measurement of antiproton interaction

Antimatter is essentially the opposite of matter, in which the subatomic particles (protons and electrons) of antimatter have charges opposite to those of ordinary matter. The findings, published online November 4 in Nature, reveal that the strong nuclear force securely binds antiprotons in close proximity with the same intensity that it does for protons inside the nuclei of atoms.

Dating back to the possible origin of universe, the Big Bang created both matter and antimatter in equal amounts. The researchers were surprised to find the no difference between matter and antimatter in the way in which their forces behaved, making them appear perfectly symmetrical.

Tang measured something called the “Strong Nuclear Force” between two antiprotons.

‘Although this puzzle has been known for decades and little clues have emerged, it remains one of the big challenges of science, ‘ said Aihong Tang, a Brookhaven physicist.

This lack of antimatter is one of the biggest mysteries of the cosmos. Antimatter is a counterpart of matter.

Researchers wanted to see if antiprotons behaved in a different way to protons, which are “mirror images”, ordinary protons.

So Michael Lisa, a particle physicist at Ohio State University in Columbus, and hundreds of colleagues tracked antiprotons inside the Relativistic Heavy Ion Collider, a 3.8-kilometer-around particle accelerator at Brookhaven National Laboratory in Upton, New York Antiprotons are among the scores of particles produced when gold nuclei collide inside the machine at almost the speed of light.

Physicist Frank Geurts explains that there are subtle differences in the way matter and antimatter interact with each other and that there is now a new way to study and understand these differences by comparison.

Physicists studying how protons interact have it easy: Just fire a proton beam at a target made of proton-filled nuclei and see what happens.

“The antiprotons look just like familiar protons, but because they are antimatter, they have a negative charge instead of positive, so they curve the opposite way in the magnetic field of the detector”, he explained.

There has to be an explanation, but at this point opinions are mixed.

Because antiprotons annihilate when they hit anything made of ordinary matter, within a fraction of a second, they usually hit the sides of the chamber that contains the collision of the gold nuclei that created them in the first place, and turn into gamma radiation.

“We see lots of protons, the basic building blocks of conventional atoms, coming out, and we see nearly equal numbers of antiprotons”, said team member Zhengqiao Zhang of the Shanghai Institute of Applied Physics, China.

That doesn’t seem to hold up however: if that were the case, the boundaries between matter-dominated and anti-matter dominated areas should be producing collisions which result in powerful gamma rays that we should be able to detect. They were able to isolate the relationships between pairs of protons from the effects of other particles such as antineutrons.