When particles collide at enormous speeds, they produce a shower of new particles. Among them are antiprotons — twins of ordinary protons but with the opposite charge. Each of these particles has its own spin, like a tennis ball sent with a twist. But whether antiprotons are actually spun up at birth has never been checked.
The authors of the study propose a way to find out. A beam of antiprotons is directed at a thin target of ordinary matter. If the antiprotons are spinning, they will deflect slightly more often to one side than the other, just as a spun ball in table tennis tends to veer sideways. This asymmetry can be spotted if enough events are collected. Computer model calculations show how many collisions are needed to reliably catch the signal.
The result matters for understanding how antiprotons interact with the nuclei of ordinary matter. Currently, this is known only approximately, and data on particle spin will help refine the theory. If the effect turns out to be noticeable, it will open a new window into the world of antimatter. If not, it will constrain the possible interaction scenarios.
Antiprotons were first produced in 1955 at the accelerator in Berkeley, and this discovery earned a Nobel Prize.
In the series 'Star Trek', antimatter is used as fuel for warp drives, and its storage requires magnetic fields to prevent contact with ordinary matter.