Scientists say the world’s largest atomic collider, the Large Hadron Collider (LHC), may have produced the top quark “quadlets” for the first time, and if confirmed, it could reveal new physics theories, scientists said. The standard model of particle physics allows for the existence of top quark “quads”, but new physics theories predict that they may be made by the LHC much more likely than the standard model predicts, and finding more of these “quadruplets” is the first step in testing these new theories.
The top quark is by far the heaviest elementary particle known: a top quark is equivalent to a tungsten atom, but its “block” is much smaller than protons, meaning that the top quark is not only the heaviest known particle to date, but also the most densemass form known to date.
Although large numbers of top quarks are produced instantaneously after the Big Bang, they disappear completely in 10-24 seconds, and large particle accelerators are now the only places where top quarks can be produced and observed.
In 1995, Fermi’s lab scientists first discovered the top quark with the use of the tevatron, then the most powerful particle accelerator. The proton-antiproton beam collision in Tevatron produces a pair of positive and reverse top quarks, but these collisions produce a pair of such quarks every few days. In contrast, a pair of top quarks are produced approximately per second in collisions between the LHC’s Hyperloop Instrument Experiment (ATLAS) and the Compact Muse Coil Experiment (CMS).
In the latest study, physicists published the results of a search for “quadruplets” in data collected between 2015 and 2018 in the ATLAS and CMS experiments. The ATLAS team announced that they had observed a 4.3 sigma rating for the birth of the quadruplets, while the CMS team said they had a confidence rate of 2.6 sigma. In particle physics, the gold standard for declaring a study “new discovery” is 5 sigmas with a confidence level of 5, so the results of the two teams are not enough to be called new discoveries.
For now, the results of ATLAS may be accidental, the researchers say, or suggest that the chances of the birth of “quadruplets” are greater than standard models predict; perhaps this is the “clue” of some new physics, “and that the data provided by the next round of data from the LHC, and the more advanced analytical techniques that may emerge in the future, will improve the accuracy of this measurement.”
It is reported that the LHC has been temporarily closed at the end of 2018, upgrades and maintenance, scheduled to restart in 2021.