When a top quark is born in a particle detector, it immediately decays into a shower of other particles. Catching a hint of new physics in that shower is like hearing a whisper at a rock concert. You need not just a good microphone, but the ability to subtract the roar of the amplifiers and the hum of the crowd.
The new method, called Optimal Observable Machine (OOM), teaches a neural network to find the observable that changes most strongly when the parameter of interest varies. The network knows in advance how the detector distorts the signal and what systematic uncertainties are possible. It's like training your ear to pick out a specific sound while knowing the acoustics of the hall and the noise of the ventilation.
The observable created by the neural network proved more sensitive than standard approaches and remained reusable for future analyses. This means that data collected today can be re-examined tomorrow with new hypotheses — without re-simulating the detector.
The top quark is the heaviest known elementary particle, and its behavior is especially sensitive to unknown forces. The new tool will help us hear even the faintest whisper of new physics in the noise of the Large Hadron Collider.
The top quark lives for only about $10^{-25}$ seconds — shorter than the time it takes light to cross a proton.