Scientists have spotted collider neutrinos at the Large Hadron Collider, which means we could find out more about new physics theories.
Scientists have been trying to detect neutrinos made in the Large Hadron Collider, but hadn’t seen any until now. The FASER collaboration was able to find some after only nine months of running the LHC and their results showed that they had spotted muon neutrinos and what might be electron neutrinos. Their findings had a really high level of certainty, 16 sigma which is way beyond 5 sigma, which is usually enough for scientists to call it a discovery. Jamie Boyd from FASER explains that this ‘exceeds [the usual] threshold for a discovery!’
FASER recently studied neutrinos and did a search for something called dark photons. Unfortunately, nothing was found from this searching. That result set limits on what kind of dark matter could exist. In the future, FASER plans to collect ten times more data which will help them look for even more interesting things as well do more testing with neutrinos.
FASER and SND@LHC are two new experiments that were built near ATLAS to observe neutrinos that come from the particle collisions during ATLAS. Recently, SND@LHC was able to announce eight potential candidate events at Moriond. The experts who work on it haven’t assessed all of the errors yet, but they think these results can be accepted with a confidence of 5 sigma. The SND@LHC detector was installed in the LHC tunnel right when Run 3 started.
So far, scientists have only studied neutrinos using experiments coming from space, the Earth, nuclear reactors, or fixed-target experiments. Neutrinos that come from astrophysics generally have high energy, like those found by the IceCube experiment at the South Pole. On the other hand, solar and reactor neutrinos usually have low energy. And neutrinos at fixed-target experiments (like CERN) have an energy range of up to a few hundred gigaelectronvolts or GeV. But new trials called FASER and SND@LHC should be able to detect much higher energies than what was seen before—between a few hundred GeV and several TeV.
Scientists are studying high-energy neutrinos from astronomical sources. These neutrinos can be made in the same way as those that come out of cosmic ray collisions with the atmosphere. These “atmospheric” ones are like a background that may get in the way of us noticing the special astrophysical ones. However, FASER and SND@LHC can help us measure this background very carefully so we can find out more about these special astrophysical neutrinos.
Scientists are using special searches to measure how fast all three types of neutrinos are produced. They will also look at the relationship between different kinds of neutrinos created by the same parent particle. This will give us important information about whether the Standard Model, which explains some things about neutrino behavior, is correct or not.