Exotic Particles form Cosmic-Ray Collisions

Our universe is made of ordinary stuff: electrons, neutrons, protons. But these particles have some weird cousins that occasionally flash into existence for just moments.

Tachyons, gluinos, photinos, axions, squarks, these are all supposed to be exotic particles, having unusual properties that can contribute significantly to the dark matter in the universe.

The interaction of a cosmic ray from outer space (typically a proton) with the atmosphere may result in the production of an exotic massive particle. This particle would be inside a shower of thousands of other particles.

However, if it is long-lived, it will survive the shower without decaying and may be detected in a neutrino telescope or other detector. Here, the researchers focused on two theoretical exotic massive particles they believe are likely produced during these interactions: the gluino, a heavy twin of the gluon, and the "weakly interacting massive particle" (WIMP), which scientists believe could be a candidate for dark matter.

"WIMPs seem undetectable among cosmic rays, but we still may have the opportunity to learn new physics from gluinos," said University of Granada physicist Jose Ignacio Illana, one of the scientists involved in the study.

Now, the scientists will have two instruments at their disposal, to help them search for these exotic particles:

The IceCube Neutrino Detector - a giant neutrino telescope under construction in the South Pole - consisting of thousands of spherical optical sensors embedded in the polar ice, covering a full square kilometer of area and designed to detect high-energy neutrinos.

The Pierre Auger Observatory - an even larger project nearing completion in the plains of western Argentina. One portion of the observatory is a grid of 1,600 giant water tanks, each mounted with photomultiplier tubes and separated from neighboring tanks by 1.5 kilometers. The tanks will detect particles based on their interactions with the water.

They have high hopes with these new instruments, as IceCube might be able to "see" the flux of gluino pairs - one pair per year, and Auger could detect 20 gluino events per year.