LHC or Create Quadruplet 'Top Quarks', Each Equals to A Tungsten Atom

The world's largest atom smasher - the Large Hadron Collider (LHC), may have "given birth" to a set of four ultraheavy particles - called top quarks for the first time, each top quark is roughly as massive as an atom of tungsten. If confirmed, it is expected to reveal new physics, according to a recent report from the American Live Science.

The standard model of particle physics allows the existence of top quarks "quadruple", but the new physics theory predicts that their probability of being manufactured by LHC may be much higher than the prediction of the standard model, and find more such foursomes is the first step in testing these new theories.

The top quarks are the heaviest known fundamental subatomic particles. Each top quark is roughly as massive as an atom of tungsten. But each top quark is much smaller than a proton, which means that the top quark is not only the heaviest particle known to date. It is also the densest mass form known to date.

Although a large number of top quarks were generated immediately after the Big Bang, they will completely disappear within 10-24 seconds. Large particle accelerators are now the only place where the quarks can be manufactured and observed.

In 1995, scientists at Fermi Lab discovered the top quark for the first time with the help of the most powerful particle accelerator at the time, the trillion-electron volt particle accelerator-Tevatron. Proton-antiproton beam collisions in Tevatron create a pair of positive and negative top quarks, but these collisions only create a pair of such quarks every few days. In comparison, a pair of the quarks are generated approximately every second in the collisions that occur in the A Toroidal LHC ApparatuS (ATLAS) and the Compact Muon Solenoid (CMS).

Physicists searched for top-quark quartets in data collected by ATLAS and CMS between 2015 and 2018. The ATLAS experiment team announced that they have seen the production of four top quarks with a sigma of 4.3. Meanwhile, in a paper published to the European Physical Journal C, researchers from the CMS experiment reported an observed sigma of just 2.6 for their quadruplet the quarks. Prior to conducting the experiment, both ATLAS and CMS expected a significance of about 2.6 sigmas. In particle physics, the gold standard for declaring a study as "discovery" is that the confidence level reaches or exceeds 5 sigmas. Therefore, the results obtained by these two teams are not enough to be called a discovery.

The researchers said that at present, the results seen by ATLAS may be accidental. it could be an indication that the production of the four quarks, each mass as a tungsten atom, is more common than the Standard Model predicts. Perhaps this is just the "clue" of some new physics, "Additional data from the next LHC run - along with further developments of the analysis techniques employed - will improve the precision of this challenging measurement." The LHC has been temporarily shut down since late 2018 for refurbishments, upgrades, and maintenance. It is scheduled to resume operations in 2021.

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