Teach First at the CERN Facility Preview for the next 3-year research campaign.
The international Advanced Search Experiments Team, led by physicists at the University of California, Irvine, has carried out the first-ever detection of candidate neutrinos produced by the Large Hadron Collider in
In a research paper published in the journal on November 24, 2021 physical review dIn 2018, researchers described how they observed six neutrino interactions during the LHC-mounted pressurized emulsion detector experiment in 2018.
“Prior to this project, there was no sign of neutrinos in the particle impactor,” said co-author Jonathan Feng, UCI Professor of Physics and Astronomy and one of the leaders of the FASER Collaboration. “This important breakthrough is a step towards developing a deeper understanding of these elusive particles and the role they play in the universe.”
He said the discoveries made during the pilot gave his team two important pieces of information.
The CERN-approved FASER particle detector for installation on the Large Hadron Collider in 2019 was recently upgraded with a neutrino detector. The UCI-led FASER team used a smaller detector of the same type in 2018 to make the first observations of the elusive particles generated in the masher. The researchers say the new instrument will be able to detect thousands of neutrino interactions over the next three years. Image source: CERN
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“First, verify that the forward position of the ATLAS interaction point in the LHC is the correct location for detecting the impacting neutrino,” Feng said. “Second, our efforts demonstrate the effectiveness of using an emulsion detector to monitor this type of neutrino interaction.”
The experimental instrument consisted of lead and tungsten plates interspersed with an emulsion layer. During particle collisions in the LHC, some neutrinos cause the solid metal core to break apart, creating particles that move through the emulsion layer and make visible marks after processing. These inscriptions provide clues about the energy and taste of the particles – tau, muons or electrons – and whether they are neutrinos or antineutrinos.
According to Feng, emulsions work in a similar way to photography in the pre-digital camera era. When 35 mm film is exposed to light, the photons leave a trail that appears as a pattern as the film is expanded. The FASER researchers were also able to see neutrino interactions after the emulsion layer in the detector was removed and expanded.
“After verifying the effectiveness of the emulsion detector approach in observing the neutrino interactions generated by the particle impactor, the FASER team is now preparing a new set of experiments with a complete instrument that is much larger and significantly more sensitive,” Feng said. .
The FASER experiment is located 480 meters from the Atlas interaction point in the Large Hadron Collider. According to Jonathan Feng, UCI Professor of Physics and Astronomy and one of the leaders of the FASER collaboration, this is a great site for detecting neutrinos from particle collisions at the facility. Image source: CERN
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Since 2019, he and his colleagues have been preparing to conduct experiments using the FASER instrument to examine the LHC’s dark matter. They hope to find dark photons, which will give researchers a glimpse into how dark matter interacts with natural atoms and other matter in the universe through forces other than gravity.
With the success of their neutrino work over the last few years, the FASER team – consisting of 76 physicists from 21 institutions in 9 countries – combined the new emulsion detector with the FASER instrument. While the experimental detector weighs about 64 pounds, the FASERnu instrument will be over 2,400 pounds, and will be more reactive and able to distinguish between types of neutrinos.
said co-author David Kasper, joint project leader with FASER and professor of physics and astronomy at UCI. “We will find the highest energy neutrino that has been produced from a man-made source.”
What makes FASERnu unique, he says, is that while other experiments have been able to distinguish between one or two types of neutrinos, they will be able to observe all three flavors as well as their antineutrino counterparts. Casper said there have only been about 10 observations of tau neutrinos in all of human history, but he expects his team will be able to double or triple that number in the next three years.
“This is a very interesting relationship with tradition in the physics department here at UCI,” said Feng, continuing the legacy of Frederick Raines, a founding faculty member at UCI who won the Nobel Prize in Physics for being the first to discover the neutrino. “
“We have produced world-class experiments in the world’s premier particle physics laboratories in record time and with very unconventional resources,” Casper said. “We owe a great debt of gratitude to the Heising-Simons Foundation and the Simons Foundation, as well as the Japanese Society for the Promotion of Science and CERN, who have generously supported us.”
Reference: “The first candidate for neutrino interactions in the LHC” by Henso Abreu et al. (FASER Collaboration), November 24, 2021, Available here. physical review d.
DOI: 10.1103/ PhysRevD.104.L091101
Savannah Shivley and Jason Arakawa, Ph.D. from UCLA. Physics and astronomy students also contributed to this research.
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