More on Particle Physics

The idea of elementary particles as the building blocks of everything – matter and forces – is one of the greatest success stories of 20th century physics.

Particle physics originated from the idea of dissecting matter in the most elementary of constituents. Ancient Greeks called them the atoms. In the past century, science has revealed a deeper, smaller realm, called the Standard Model: three families of fermions and four fundamental interactions that make up all we see around us. A key part of the Standard Model is the Higgs boson, which was observed in 2012.

But there are still questions to be answered beyond the Standard Model. It only describes five percent of the known universe; the other 95 percent is still unknown and is in the form of what we call “dark matter” and “dark energy”. And there are still questions within the Standard Model itself. What provides for the hierarchy of masses between families? Why is gravity so weak compared to the other forces of nature?

These are some of the questions particle physicists at PI are trying to address. Their work has great overlap with astrophysics and cosmology. Besides pursuing new theoretical directions, they also design new experiments that promise to shed light on these questions. These experiments range from dark-matter and hidden-sector searches at particle colliders and underground facilities, to new techniques for table-top experiments seeking to detect new forces and gravitational waves.

Tracks of many particles emerging from the collision of two protons