By Alicia Shephard, British Science Festival

Physicists have been guided on a journey of discovery by the Standard Model of Physics since 1970. This model aims to explain the interactions of core constituents of matter, as governed by four fundamental particles. However, this is a complex aim as it attempts to explain everything from the movement of planets and black holes down to electrons and atoms. The discovery of the Higgs Boson by Professor Jon Butterworth and his team of researchers at the large Hadron Collider, CERN, has closed the chapter on the Standard Model. However, the end has not yet been written as the model fails to include gravity. Until we find a model that encompasses everything, particle physics remains incomplete. 

In Jon’s talk at this year’s British Science Festival he took the audience on a journey through the invisible world that is particle physics. He began his journey with the first fundamental particle: the electron, which is considered a fundamental particle because it does not contain any smaller particles and therefore can’t be split. Discovered 100 years ago the electron became a ‘gateway into the world of subatomic particles.’ 

A map of the invisible universe as seen in Jon Butterworth's book: A map of the invisible journeys into particle physics.

Since the discovery of the electron in 1987 scientists have worked tirelessly to uncover what other constituent building blocks may be present in our universe. The final particle to be discovered was the Higgs Boson in 2011. This particle had been theorised to exist since the 1960s due to the unexplained mass of other fundamental particles known as quarks, which by definition contain nothing and therefore should have no mass.  

Mass was therefore concluded to be something which particles could not get because of their own internal properties but rather something gained from interacting with the Higgs field, a ‘field that fills the whole universe’.  Thinking of a field as being like a body of water, Prof. Butterworth invited listeners to envisage how the field can ripple and move. Drop a grain of sand into this body of water that’s constantly in flux and you won’t see much of an effect. But throw in a rock and the effect is much starker, with ripples extending in all directions from where the rock entered the water. To detect any change in the Higgs field then, you need a very large event indeed.  

Enter the Large Hadron Collider. The particle collider’s role was to do just that, power the collision of two proton particles with the use of a 27km ring of superconducting magnets. At the point of collision there was predicted to be a ‘bump’ in the data which would indicate a new particle.  

A Large Hadron Collider (Picture: Wikimedia Commons)

Despite the difficulties of trying to identify something which decays at 10-25 of a second, and years of repeating experiments to ensure maximum precision, the Higgs Boson was identified due to the expected high energy ‘bump’ in the data. 

So, the Higgs Boson has been found, but what do we do with it now? When questioned on this Prof. Butterworth was uncertain about any current applications which may have arisen for the particle. However, he stated, ‘it’s new science’ and it has not yet had time to be applied. Despite this, the facilities at CERN themselves have already contributed to science and technology in other ways, for example through touch screen technology. So the project has already contributed positively to society and it is likely it will continue to do so.  

In theory the discovery of the Higgs Boson completes the Standard Model of Physics. But the Standard Model remains incomplete, failing to account for the very force which keeps us grounded- gravity. Particle physics is now entering an era without rules and theories to guide researchers. It’s an exciting and scary time and, as Jon says, there is not simply a ‘theory for everything’.  

Find out more about the British Science Festival here.