Credit: Brookhaven National Laboratory
Telltale signs of a lambda hyperon (Λ) decaying into a proton (p) and a pion (π-) as tracked by the Time Projection Chamber of the STAR detector. Because the proton comes out nearly aligned with the hyperon's spin direction, tracking where these "daughter" protons strike the detector can be a stand-in for tracking how the hyperons' spins are aligned.