Particle Physics

Particle physicists study the smallest things in the universe and the forces that govern their behaviour. One aim of particle physics is to understand what happened during the big bang on a fundamental scale, and the evolution of our universe from these early conditions.

Particle physicists use giant accelerators to get particles to speeds close to the speed of light. These particles can then be smashed into each other creating high energy collisions. These collisions must be head on in order to produce the very high energy that is required for new particles to be created. These high energies are similar to those at extremes in the universe such as the big bang and black holes, which is why there was a lot of hype when The Large hadron Collider was started that it may create a black hole. At these limits our current knowledge of Physics breaks down and so they are of huge interest to a range of Physicists. In order to produce these high energy head on collisions very precise calculations must be made. For example at CERN they have to account for tides and the vibrations from vehicles. These particle accelerators can be better understood by imagining that you want to know what makes up watches in a bid to understand what’s going on inside them. If you smash two watches together they would smash open and if you did enough collisions you may be able to find the parts you were interested in. In particle collisions, many particles are created which can then be studied to give information about the basic forces and constituents of nature. Theoretical particle physicists look at the particles created in these experiments and form ideas as to how they came about.

The standard model is the current model used by particle physicists to describe three of the four fundamental forces and their subatomic particles. The standard model must have been very satisfying to watch grow, with physicists predicting new hypothetical particles and then confirming them in experiments. We now have a large model containing sixty one elementary particles. This is not to say that the book is closed - the standard model is known as ‘the theory of nearly everything’. Although successfully predicting certain results it falls short in a couple of respects. Firstly there is the problem of gravity, which refuses to be unified with the other forces. The standard model also fails to predict the expansion of the universe, and struggles to explain the oscillation of neutrinos, or how they have mass. Particle Physicists are trying to find ways in which they can extend the standard model to become the grand unified theory of everything.

Particle physics aims to describe the smallest constituents of matter and how they interact. It also examines the behavior of particles that have are travelling close to the speed of light. For this reason, it has applications in most realms of physics. Particle physicists are involved in many exciting projects, from understanding black holes to searching for dark matter and extra spatial dimensions. But not all particle physics is this far removed from everyday concepts - particle physics is also involved in projects such as developing hospital scanners and computer programs.

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Our blog posts are often written by scientists about their ongoing research

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