Investigating the stickiest glue in the Universe
Even the Universe finds itself fragile enough to need a little glue to keep itself together. Scientists at Brookhaven National Laboratory aim to learn more about this mysterious glue that is responsible for all visible matter.
Our understanding of the atom and its nucleus has served humanity well in the last 100 years, allowing for the exponential and perpetuating boom of all modern research. What we know about the atom though is just a fraction of available knowledge that we can extract from them.
Scientists at the Brookhaven National Laboratory plan to build a new particle collider called the Electron-Ion Collider to observe the “glue” that keeps the Universe together.
The Science and Technology Facilities Council (STFC) provided £3 million in funding toward the Electron-Ion Collider in 2021. This funding has allowed the STFC Technology Department and RAL’s Particle Physics Department to be instrumental in establishing UK leadership in the development of the detectors of the new Electron-Ion Collider.
A brief history of a two-and-a-half thousand-year journey
Around two-and-a-half thousand years ago, Greek philosopher’s Leucippus and Democritus introduced the concept of tiny, indivisible particles, which they called “atomos” meaning “uncuttable”. The concept of these particles was quite simple though, and not quite as sophisticated as today’s ideas: it was believed that if a tree were cut into these particles, you would discover tiny tree particles!
It wouldn’t be until nearly 2,300 years later, in the 19th century, that John Dalton would come up with the atomic theory, proposing that atoms are indestructible and form chemical compounds such as water and salt.
Just 100 years later, in 1897, J.J. Thomson discovered the electron, a particle 1,000 times lighter than Hydrogen. And this discovery gave rise to the “plum pudding” model of an atom.
In 1911, Ernest Rutherford found the presence of a dense, positively charged nucleus at the centre of atoms. This led to Neils Bohr proposing his “Planetary Model of the Atom” in 1913, where electrons orbit the nucleus like planets around a star. And then in 1919, Ernest Rutherford identified the positively charged particle as the proton.
Continuing in the early 20th century, scientists like Erwin Schrodinger amongst other notable scientists, developed mathematical principles that describe the behaviour of particles on the atomic scale. This led to the idea of the wave-particle duality, where electrons behave both as waves and particles, and are described through probabilities.
Our understanding of the atom and its nucleus since the dawn of the idea from Leucippus and Democritus has been a long journey, but one that has served humanity well in the last century or so, not only in scientific research but in advancements in technology. Because of it, we have discovered more elementary particles, one of which scientists are desperate to know more about.
The most important glue in history
In the early moments after the Big Bang, the Universe was a hot and dense mess of energy, known as a quark-gluon plasma. In this unique state, the building blocks of atoms called quarks and gluons roamed freely.
Amid this extreme environment in the earliest moments of our Universe, the strong [nuclear] force played one of the most important roles in history. As the strongest of the four fundamental forces, it ignored the natural repulsion between positively charged protons, and was so strong that it could hold them together to form the centre of atoms. Imagine being able to make two positive magnets touch and then hold them there for eternity…
For this to work, the strong force relies on a “force carrier” called a Gluon. Aptly named for its glue-like properties that bind positively charged protons together. Without these force carriers, atoms would collapse, and our Universe would look completely different, and our existence would not be possible.
As the Universe expanded and cooled, the strong force became strong enough to confine the building materials of atomic nuclei into the more familiar protons and neutrons, which formed an abundance of the first ever atoms: Hydrogen and Helium.
And in this grand and seemingly infinite landscape, this abundance of Hydrogen and Helium led to the formation of the very first stars and galaxies, eventually forming our Milky Way. Despite the vast expanse of our galaxy, 100,000 light years across, the strong force only operates with a range of one million billionth of a meter. Yet, its incomparable strength in binding particles is responsible for not just its existence, but the existence of all visible matter.
Scientists are still seeking answers about how Gluons played a role in creating visible matter and left a scattering of Hydrogen in the Universe. And it’s with the Electron-Ion Collider that scientists hope to unlock crucial insights into the origins of our Universe and the forces that govern it.
Smashing particles again seems like a sensible idea
It turns out that smashing particles together is a sure way of getting big answers for humanity’s most philosophical questions — just take the discovery of the Higgs boson as an example!
The Electron-Ion Collider will be a 2.4-mile circumference particle collider and will be the only one of its kind. On the surface, its layout and objectives are like those at CERN’s Large Hadron Collider.
The fundamental difference though is that the Electron-Ion Collider will steer beams of high-energy polarised electrons into collisions with polarised protons and atomic nuclei to provide insights into the fundamental forces and interactions of matter at the smallest possible scale.
The impact of the Electron-Ion Collider extends far-and-wide into some of the most important areas of modern-day research, offering possibilities for progress and innovation. Not only will this deepen our understanding of the world around us, but can lead to advancements in cancer research, the development of other drugs and medical treatments, and develop next generation computer chips, solar cells, and batteries.
Into the technicalities of Time(pix)
To answer some of the most thought-provoking questions in Science, the Electron-Ion Collider will need a detector capable of measuring the energy, position, and time of arrival of charged particles produced by the collisions. It just so happens that CERN have one that fits the bill.
The detector, called Timepix, is an electronics read-out chip, which combined with a semi-conductor, forms a detector capable of making these extreme measurements.
The pixel size of the chip is small enough to allow the detector to track the paths of individual particles with extremely high precision. This will allow researchers to observe the complex interactions that take place during the collision events and extract information about the fundamental forces and particles involved.
The Nuclear Physics Group at STFC Daresbury’s Technology Department is working with the University of Glasgow to build a prototype of a modified Timepix detector that would be suitable for the Electron-Ion Collider. The prototype will be submitted for approval to the Brookhaven National Laboratory later this year.
ITS3 for 2
Alongside its extremely accurate detector, the Electron-Ion Collider also requires an Inner Tracking System, an essential component of a particle collider. Without it, the collider would not be able to track the trajectories of charged particles produced in the collision events. A detector without a tracking system would be of no use to anyone.
Fortunately, the specifications for the Electron-Ion Collider are identical to the specifications of a brand-new Inner Tracking System (ITS3) being designed for CERN’s ALICE detector by STFC’s Technology Department in collaboration with the University of Birmingham.
And so, the two projects are merging and combining forces in the development of the tracking system.
Story by: Jake Hepburn
Interested in particle physics? Want to know what next-gen particle accelerators might be looking for? Check out our feature exploring the search for physics beyond the standard model!
