How Charge Flows from Z-Boson Decays ✎ express
In 1994–1995, the LEP accelerator collided electrons and positrons, producing Z bosons that promptly decayed into showers of particles. The DELPHI detector recorded these events, and now, decades later, a new pattern has been found in that data: the electric charge within particle jets is not distributed randomly but follows a simple sine curve.
Looking at the emission angle of particles relative to the collision axis, the charge flow varies as sin(2θ). This pattern arises because the Z boson interacts differently with left-handed and right-handed particles — a property of the weak interaction that violates mirror symmetry. This effect had not been isolated in charge flow before, but now it is visible directly in the data.
The measurement shows that such charge flow can be reliably extracted from experiment, carefully accounting for detector distortions. This paves the way for new tests of the Standard Model: if traces of unknown particles exist in Z-boson decays, they may show up precisely in such subtle correlations.
The data analyzed by the authors were recorded in the last century, yet they remain valuable: the LEP accelerator has long been dismantled, but its archive continues to yield new results.