Inevitably, a hangover followed. The leading idea for how to push physics beyond the Standard Model – and explain the many remaining mysteries of the universe – is looking shaky. Thousands of physicists have spent their career carefully constructing the theory, called supersymmetry. It has taken almost four decades. But, so far, the most powerful particle accelerator ever built – the Large Hadron Collider (LHC) at Cern, near Geneva – has not found any hard evidence to back up the theory.