Neutrinos created in a particle accelerator have been spotted for the first time.
Researchers at CERN’s ForwArd Search ExpeRiment (FASER) have discovered neutrino candidates in a particle accelerator for the first time, according to a research published in the peer-reviewed journal Physical Review D on Wednesday.
Neutrinos are the universe’s most prevalent fundamental particles with mass, and they’ve been found in a variety of places, including the sun and cosmic-ray interactions. Neutrinos produced within a particle collider have never been directly detected, making them one of the least understood particles in the standard model of particle physics.
Collider neutrinos are created at extremely high energy, where neutrino interactions are poorly understood. The ability to detect and study collider neutrinos could provide insight into the particles because it would allow scientists to study them under extremely controlled conditions.
According to CERN, in 2019, Jamie Boyd, co-spokesperson for the FASER experiment, said, “These neutrinos will have the highest energies yet of man-made neutrinos, and their detection and study at the LHC will be a milestone in particle physics, allowing researchers to make highly complementary measurements in neutrino physics.” “Moreover, FASER could pave the way for neutrino programs at future colliders, with the results of these programs feeding into discussions of proposals for even larger neutrino detectors.”
According to UC Irvine News, the FASER team, led by physicists from the University of California, Irvine, recorded six neutrino interactions during a pilot run of a small emulsion detector at CERN’s Large Hadron Collider (LHC) in 2018, just before the LHC went down for maintenance and upgrades.
Lead and tungsten plates alternated with layers of emulsion in the detector. Some of the neutrinos created at the LHC collide with nuclei in dense metals, resulting in particles that pass through the emulsion layers and leave markings that may be seen after processing. The marks can reveal information about the particles’ energy, allowing scientists to figure out what type of particles they were.
“This remarkable accomplishment is a step toward establishing a deeper understanding of these elusive particles and the function they play in the cosmos,” study co-author Jonathan Feng, UCI Distinguished Professor of physics and astronomy and co-leader of the FASER Collaboration, told UC Irvine News.
According to Feng, the discovery provided the FASER team with two critical pieces of information: It confirmed that the device’s location in the LHC is optimal for detecting collider neutrinos and established that an emulsion detector can detect neutrino interactions.
The team’s findings had a statistical significance of 2.7 standard deviations, which is barely below the three standard deviations required in particle physics to claim evidence of a particle or process.
“Now that the effectiveness of the emulsion detector approach for observing the interactions of neutrinos produced at a particle collider has been confirmed, the FASER team is planning a new series of experiments with a full instrument that is much larger and significantly more sensitive,” Feng said.
The gadget that led to the discovery is simply a prototype for a much larger device that will be operational after the LHC resumes operating in 2022. The ultimate device will weigh more than 2,400 pounds, but the pilot detector will only weigh around 64 pounds. The final device will also be significantly more reactive and capable of distinguishing between different neutrino types.
According to CERN, after the full-fledged detector becomes operational in the next LHC run, from 2022 to 2024, the FASER team expects to see roughly 20,000 collider neutrino interactions.
Researchers want to detect dark photons, which would indicate how dark matter interacts with normal atoms and other matter in the cosmos through nongravitational forces, with the final gadget being used to explore dark matter at the LHC.
When the LHC reopens in 2022, the Scattering and Neutrino Detector (SND@LHC) will work to detect and investigate neutrinos as well, although from a different perspective than FASERv. The detector will also be able to look for novel particles, such as very weakly interacting particles that aren’t anticipated by the Standard Model and could be the source of dark matter.