Researchers from Princeton University have announced that they have traced the fifth and most prominent way that Higgs boson particles decay into other particles. The team says that the findings cap years of exploration into the particle and give them new pathways to study the physical laws governing the universe. The study looked at the way Higgs particle decays into two other particles called bottom quarks.
The team says that this pathway is the last to be detected of the five main signature pathways used to identify Higgs particles. Researcher James Olsen says that the team found it exactly where they expected to find it. Higgs particles exist for short periods before transforming into other so-called “daughter” particles. The boson lasts for one septillionth of a second, so scientists use the daughter particles to confirm evidence that the Higgs boson existed.
Daughter particles are scattered among the particles created from the collision of two protons at the Large Hadron Collider. That is where the Higgs particle was first observed back in 2012. It was observed then via three of the other modes of decay. Of the modes of decay, decay into two bottom quarks occurs most often. The team says that makes up about 60% of the decay events from the Higgs.
The catch is that the bottom quark is the hardest to track back definitively to the Higgs particle because other particles can also produce bottom quarks. A quark is a tiny constituent of a proton, which are among the building blocks of atoms. When produced, bottom quarks split into jets of particles making it hard to trace them back to original parent particles. Two main Higgs detectors at the LHC are called the Compact Muon Solenoid or CMS and the ATLAS and are operated by different teams.
Those two main detectors also have smaller detectors arranged like layers of an onion. The detectors can detect particles at each layer of the onion and reconstruct their paths. This allows tracking the path of a particle back to its source to identify where the Higgs first formed in the proton-proton collision. The biggest challenge has been to separate the Higgs created bottom quarks from others and the ability to do so has taken the researchers ten years.
SOURCE: Princeton University