Sometimes discoveries in science turn up where you are looking for them, like finding treasure near a shipwreck. At other times they seem to appear from nowhere, as if they’ve fallen from the sky. In particle physics there are plenty of examples of both kinds, but all discoveries have one thing in common. As soon you find something new – whether it’s expected or completely out of the blue – you go back through the analysis with a fine tooth comb, making sure that you’ve missed nothing. Is there a detail you’ve forgotten? Have you overlooked some aspect that could mimic the effect of something new?
It’s at this stage that you make your results known to the jury of your peers – other scientists working in the same area who look at what you’ve done and see if they can find anything you might have missed. Then, to quote one of the famous fictional detectives, Sherlock Holmes, “when you have eliminated the impossible, whatever remains, however improbable, must be the truth”.
This is particularly the case when a result is completely unexpected. In a sense, it’s all down to detective work, and the experimenters must make sure that they are interpreting all the evidence correctly before identifying the suspect.
The curious case of the speeding neutrinos – apparently breaking nature’s speed limit of the velocity of light as they fly from CERN to the OPERA experiment in central Italy – is now open to the jury. The OPERA collaboration has been able to find no explanation in terms of the experimental set up for this effect. So the researchers have revealed what they observe to their peers through a paper posted on arXiv.org that explains all the steps from data collection to the final analysis, and through a talk at CERN. Neutrino experiments are notoriously difficult because neutrino interactions are so rare, but over the coming months – and indeed years – the teams working on similar experiments elsewhere will scrutinise their data to see if they see the same effect.
This is the way that science works all the time, not just when a surprise effect appears like an unexpected guest at a party. Results are checked by others, questions can be asked – and answered – and when everyone is satisfied that nothing has been overlooked, then the results are published. Of course, wrong results do get published and surprising effects can fade away as further experiments fail to find fresh evidence. Again, this is all part of the scientific process; far from being a straight line like a Roman road linking major discoveries, it wanders more like river that changes direction in response to the landscape it crosses,
So the OPERA results are now coming under close scrutiny in the particle physics community, and it will be fascinating to see whether they do eventually stand the test of time. Then, and only then, if the results remain, fulfilling Sherlock Holmes’s requirement, would super-fast neutrinos become established, not as science fiction, but as science fact. For now, however, we have to wait and see.
Christine Sutton
