In huge news for the physics world, scientists have made the first unambiguous observation of Higgs boson decay into a matter-antimatter pair of bottom quarks. If this makes no sense to you - don’t panic - it relates to the highly exciting and highly complex world of the Large Hadron Collider (LHC).
The LHC is the world's largest particle accelerator. Its essential function is to smash together two beams of protons traveling at nearly the speed of light. In 2012, it found the Higgs boson particle.
Large Hadron Collider key to observing decay
When the LHC creates a particle impact, new particles are created which are observed by detectors around the point of collision. Even with the LHC, there is still only a one in 10 billion chance of a Higgs boson appearing and being detected.
To find the Higgs boson, the LHC smashed together trillions of particles and used a supercomputer to analyze all the resulting data. The news today that confirmed the observation of the Higgs boson decaying into a matter-antimatter pair of bottom quarks has the potential to set new constraints on fundamental physics.
The confirmation shows a strong agreement between long-held physics theoretical predictions and experimental data. Bosons have an incredibly short lifespan, roughly 10^minus 22 seconds.
This means that when traveling at the speed of light, the particle has decayed long before it travels a distance the size of an atom. Therefore, it is only possible to witness the products of the decay and use that information to make assumptions about the parent boson.
Observing these decays was made even more difficult by the act that a Higgs boson is made in only one collision in every 1 billion collisions inside the LHC. All these collisions are also generating the production of bottom quarks, so the Higgs bosons decaying into bottom quarks is totally swamped by pairs of bottom quarks made by more ordinary processes.
It seemed impossible to separate out these events in order to identify the decay of the Higgs boson from the others. In order to do so, scientists had to take a new approach. They began to examine a different class of collisions where a Higgs boson was produced at the same time as a W or Z boson.
LHC will be refurbished to increase capabilities
This class of collisions is known as "associated production." W and Z bosons decay in distinct and easily identifiable ways. Despite associated production happening less often than non-associated Higgs production, the presence of W or Z bosons greatly increases the chance for the researcher to identify events containing a Higgs boson.
Research into its decay will continue until December when the instrument will pause its operations for two years for refurbishment and upgrades. In the Spring of 2021, the LHC will resume operations with enhanced capabilities that will no doubt open even more doors into the mysterious world of the Higgs boson.
“These beautiful and early achievements also underscore our plans for upgrading the LHC to substantially increase the statistics. The analysis methods have now been shown to reach the precision required for exploration of the full physics landscape, including hopefully new physics that so far hides so subtly,” said CERN Director for Research and Computing Eckhard Elsen.