What do physicists do when theory suggests that something should exist, but we haven’t proved that it does? They search for evidence, and they search with sophisticated experiments that delve into any aspect that could prove (or disprove) a hypothesis.
A good fraction of particle physics therefore comes down to searches. Searches for the Higgs boson, exotic particles, dark matter. Whilst most of these experiments don’t directly make a discovery, they help significantly by ruling out experimental regions that they prove does not contain the particle they hunt for. That’s why our image of the week comes from a review in JPhysG studying the direct detection of dark matter.
The image above shows the upper-limit exclusions on cross-sections for one of the leading candidates to explain dark matter: Weakly Interacting Massive Particles (WIMPS). Naturally, this is just one facet to the hunt. Each experiment will have different capabilities and specialisms that make them suited to ruling out or finding new physics in the specific area they target.
These exclusion graphs, compiled form many experiments, help both theorists and experimentalists know where to look next, and are a vital part of the scientific process of discovery. Should a discovery be made, there will be a lot to thank these experiments for for paving the way forward.
This work is licensed under a Creative Commons Attribution 3.0 Unported License
Image of the week: from Teresa Marrodán Undagoitia and Ludwig Rauch 2016 J. Phys. G: Nucl. Part. Phys. 43 013001. Copyright IOP Publishing.
Categories: Journal of Physics G: Nuclear and Particle Physics, JPhys+