Stories tagged high energy physics

Mar
06
2010

RHIC collision of gold ions: The tracks indicate the paths taken by thousands of subatomic particles produced in the gold ion collisions at RHIC.
RHIC collision of gold ions: The tracks indicate the paths taken by thousands of subatomic particles produced in the gold ion collisions at RHIC.Courtesy Argonne National Laboratory
A heavy isotope of antihydrogen was created at the Relativistic Heavy Ion Collider (RHIC) on Long Island, New York. This antihydrogen isotope was heavier than the previous antimatter record-holder, antihelium. I say "was", because it only lasted a few hundred trillionths of a second.

Super smash-up

To make the antimatter, physicists smashed two gold nuclei against each other with enormous energies. The data resulting from the collision "literally looked like haystacks". Sophisticated software was used to make sense out of the debris and pick out the new antimatter.

To form the new antihydrogen isotope, first an antistrange quark binds with an antiup and antidown quark to make an antilambda -- an antineutron-like particle. The antilambda, which is fractionally heavier than a neutron, must then combine with a conventional antineutron and an antiproton. The chances of this happening are very slim: out of 100 million collisions, RHIC generated just 70 of the new antihydrogen isotopes.

Why?

Studying the properties of antinuclei such as these might help physicists study the primordial form of matter that existed in the universe shortly after the Big Bang and why the Universe is full of matter rather than antimatter.

Source article
Heavy antimatter created in gold collisions Scientific American