The writer’s latest book is How to Grow a Man
Whatever may have finally arisen from the excitement that particle physicists may have discovered a new secret of the universe, one thing is for sure, the process shows that science is working at its best. Political ideologues may want to claim justification for an innermost idea. But scientists can be filled with delight when their theories don’t work.
Hubbub followed an experiment at the Fermi National Accelerator Laboratory in Illinois that yielded a result that may differ from what the theory predicts. From such discrepancies, scientific knowledge is found, even if the discrepancy is small ̵
The difficult part explains what was measured in the Muon g-2 experiment and what the discrepancy suggests. Muons are similar to electrons orbiting atoms, but are more massive: plum to pea electrons. Both act as small magnets, and the experiment measures the strength of this magnetism – quantified by a number denoted by “g” and revealed by how many muons oscillate as they rotate in a magnetic field.
The theory used to predict “g” is based on the so-called standard model of physics, which describes all known basic forces and particles in our universe. If the prognosis has come out, even with a small difference, something must be missing: an extra particle or force that they have never seen before. That the predicted “g” may differ from its measured value was disputed 20 years ago. This new experiment suggests that the difference may be real.
If so, this would be more dramatic than the famous discovery of the Higgs particle in 2012. Almost everyone was convinced that Higgs had to exist, as this was the last missing piece in the Standard Model. Yet we also know that this model cannot be a complete account of the world. First, it does not reconcile the two deepest theories of physics: quantum mechanics and general relativity. Nor does it explain the existence of dark matter, a hypothetical substance needed to explain why space looks the way it does.
Theoretical physicists have long constructed theories that go beyond the standard model. But we can’t verify that they’re true without experimental guidance on where the model breaks down. The result was very well argued, but no progress. So particle physicists have been looking for experimental results in which the model seems to be insufficient. Now they may have found him.
If the discrepancy is true, it could mean some new natural force that has given the muons an extra boost. Since every force in physics has a connected particle, this implies a new particle – one that other experiments can look for afterwards.
However, keep in mind that several earlier claims about a possible “new physics” outside the Standard Model have evaporated. Also, the calculations behind the theoretical prediction of this experiment are devastating and rely on approximations that leave room for twisting. Some physicists claim in an article published last week that the measured result may actually be fully compatible with the standard model. So anything can be a false alarm.
For now, this leaves more questions than conclusions. The findings will not explain dark matter or prove string theory; at best, they offer a vague hint of the way forward. However, the broader message is extremely necessary in these rapidly changing and difficult times: acquiring new knowledge requires patience and care, an open but perceptive mind and acceptance of insecurity.