Scientists have made a neutrino discovery using a particle collider – an innovation that will deepen scientists’ understanding of subatomic particles.
Subatomic particles were first discovered in 1956 and play a vital role in the process that makes stars burn. The neutrino discovery, driven by a team at The University of California, Irvine, could also shed light on cosmic neutrinos that travel large distances and collide with Earth – providing insights into distant parts of the Universe.
The particle detector, named the Forward Search Experiment (FASER), was designed and built by an international group of physicists and installed at CERN, the European Council for Nuclear Research, in Switzerland. FASER is the first of its kind to detect neutrinos.
The role of neutrinos in particle physics
The first neutrino discovery was made almost 70 years ago by Frederick Reines, a UCI physicist and Nobel laureate. They are the most abundant particle in the cosmos and “were very important for establishing the standard model of particle physics,” said Jamie Boyd, a particle physicist at CERN and co-spokesman for FASER. “But no neutrino produced at a collider had ever been detected by an experiment.”
Since the groundbreaking discovery made by Reines and contributions from other scientists, most neutrinos studied by researchers have been low-energy neutrinos. The brand-new neutrino discovery is one-of-a-kind – they are the highest energy ever produced in a lab and are similar to the neutrinos found when deep-space particles trigger dramatic particle showers in our atmosphere.
Boyd explained: “They can tell us about deep space in ways we can’t learn otherwise. These very high-energy neutrinos in the LHC are important for understanding exciting particle astrophysics observations.”
Particle colliders: Paving the way for a new, unique neutrino discovery
“We’ve discovered neutrinos from a brand-new source – particle colliders – where you have two beams of particles smash together at extremely high energy,” stated Spokesman Jonathan Feng, a UC Irvine particle physicist who initiated the neutrino discovery project.
This project involves over 80 researchers at UCI, along with 21 partner institutions. Brian Petersen, a particle physicist at CERN, announced the results Sunday on behalf of FASER at the 57th Rencontres de Moriond Electroweak Interactions and Unified Theories conference in Italy.
FASER is designed to search for new and undiscovered light and weakly-interacting particles and studies the interactions of high-energy neutrinos.
In contrast to other detectors at CERN, such as ATLAS, FASER only weighs around one tonne and fits neatly into a small side tunnel within its facility, meaning it took only a few years to design and construct using spare parts from other experiments. Previous detectors have stood several stories tall and weigh thousands of tonnes.
“Neutrinos are the only known particles that the much larger experiments at the Large Hadron Collider are unable to detect directly, so FASER’s successful observation means the collider’s full physics potential is finally being exploited,” said Dave Casper, an experimental physicist at UCI.
What’s next for FASER?
Beyond neutrino discovery, another of FASER’s chief objectives is to help identify the particles that make up dark matter. According to physicists, dark matter makes up most of the matter in the Universe; however, it is a mystery as it has never been directly observed.
FASER has yet to find signs of dark matter, but with the LHC set to begin a new round of particle collisions in a few months, the detector stands ready to record any that appear.
“We are hoping to see some exciting signals,” Boyd concluded.