PARTICLE physics finds itself in testing times. This branch of science aims to describe the universe by pulling it apart into its most fundamental building blocks, or particles, and putting them back together in a way that explains how everything works.
Its most robust attempt, the standard model, explains the subatomic world with incredible precision 鈥� but falls short in some big ways, lacking the parts to explain gravity, dark matter and dark energy for instance.
Advertisement
Theories like supersymmetry, and those on extra dimensions and novel forces, seek to provide the missing pieces. Almost all of these predict new particles that the Large Hadron Collider at CERN near Geneva, Switzerland, is powerful enough to discover.
The anticipation of finding such a particle may explain what happened when a small bump showed up in LHC data at the end of 2015. This could have been the first sign of a heavier particle predicted by supersymmetry. A flood of more than 500 theory papers attempted to explain it.
But after adding data taken at the LHC so far in 2016, the bump went away. The 2015 signal was just noise after all.
This prompted questions about the wisdom of pursuing proposals for . Some go as far as to call this no-show a 鈥� but it is too early to make that call.
We experimentalists will go on searching for these particles using the LHC. It is due to deliver 100 times more data than collected so far. Admittedly, we will have to start wondering what to do if nothing new shows up at all.
Are things only real when we look at them? Collapse: Has quantum theory鈥檚 greatest mystery been solved?
A machine bigger than the LHC would cast the net for heavy particles wider, and perhaps finally confirm or rule out theories such as supersymmetry. It would be a costly global effort. CERN, China, Japan and the US are vying to host such a facility.
To undertake such a project would require thousands of people and billions of dollars over decades. But the economic case is strong: projects like this pay for themselves through spin-off technologies, and by inspiring and training future science, maths and engineering graduates.
The main deciding factor, however, must be the scientific case. If we still have no clear sign that such a machine will be able to discover or study the particles new theories predict, the money may be better spent on many smaller facilities that can test the standard model in ways not possible at the LHC.
The next five years will be crucial to that decision. It is time for creativity, hard work and some bumps along the way. At stake is a revolution in our understanding of the universe, and the future direction of global research in fundamental physics.
This article appeared in print under the headline 鈥淩eality check鈥�