The discovery of the Higgs boson in 2012 has proved to be a source of rich speculation for particle physicists. In 2019, researchers proposed that three types of very high-energy Higgs Bosons, dubbed the “Higgs Troika”, may have played a role in ridding the infant universe of most of its antimatter. The Higgs boson may also reveal insights into the nature of dark matter and dark energy, the so-called “dark sector” that comprises 95% of the Universe.
The Dark World May Not Be Built on a Single Species
“Our ordinary matter (baryonic matter) enabled us to have such a rich and beautiful world,” astrophysicist Zhen Liu at the University of Minnesota wrote in an email to The Daily Galaxy. “Ordinary matter only makes up about 15% of the matter content of our universe; dark matter (DM) makes up the rest of the matter content,” he explained. “Why do we expect DM to be a single species, lifeless, dull, and boring? It is entirely reasonable, even more probable, to have a dark world built upon the dynamics of dark matter. Given Einstein’s mass-energy equation, there is more energy in the dark world than in our luminous world. We cannot associate the dark energy to either world (yet) as it is another mystery of our universe.”
A Breathtaking World
“Higgs boson, a critical component of the Standard Model that helps enable many dynamics, could also play the role of the portal between the luminous world and the dark world through its quantum mechanical couplings,” Liu wrote in his email. “Through such coupling, we might directly observe the decay or transitions between different states of particles that exist in the dark world. Even better, through our great control of the Higgs boson production at the Large Hadron Collider and future colliders, we might even directly produce dark-world particles and detect them. I cannot imagine how breathtaking the world would be when we master and control luminous matter and dark matter.”
The Mystery of the Missing Antimatter
The Standard Model fails to explain why the observable universe contains virtually no antimatter. Such gaps have inspired physicists to search from subatomic particles to galaxies for laws of nature beyond the Standard Model. Particles of antimatter have the same mass but opposite electrical charge of their matter counterparts. For example, the positively charged positron is the antimatter counterpart of the negatively charged electron. When an electron and positron collide, they annihilate each other, producing a pair of photons that conserve energy and momentum.
Physicists believe that there were equal amounts of matter and antimatter in the early history of the universe – so how did the antimatter vanish?
The Higgs Troika
Physicists from Brookhaven National Laboratory and the University of Kansas suggest that a stream of matter was being created by the three particles as they decayed just after the Big Bang. They further noted, reported Science X: “that a lot of those particles that made up that matter would meet with antimatter particles, resulting in the annihilation of both. If this went on for a length of time, most of the antimatter in the universe would have disappeared. But there would have been enough matter generated by the Higgs Troika remaining to comprise all the baryonic matter observed in the universe today.”
For the scenario to work, the researchers noted, there would have to have been two as-yet undiscovered Higgs particles, in addition the one identified in 2012 that would have required high enough energies to generate matter when they decayed. Also, the time frame during which the antimatter was being lost would have been short, before the four energy forces split into their natural states.
The Higgs is possibly the last holdout particle in physicists’ grand theory of how the universe works, discovered at the Large Hadron Collider (LHC; above) in 2012. “We know for sure there’s a dark world,’ said LianTao Wang, with the Enrico Fermi Institute and the Kavli Institute for Cosmological Physics at University of Chicago, “and there’s more energy in it than there is in ours. It’s possible that the Higgs could actually decay into these long-lived particles.”
Wang’s paper outlined a method to directly detect particles from the ‘dark world’ using the Large Hadron Collider. Until now we’ve only been able to make indirect measurements and simulations, such as the visualization of dark matter.
Wang, who studies how to find signals in large particle accelerators, along with scientists from the University and UChicago-affiliated Fermilab, think they may be able to lead us to its tracks; in a paper published in Physical Review Letters, they laid out an innovative method for stalking dark matter in the LHC by exploiting a potential particle’s slightly slower speed.
“Through new ideas using precision timing information and fine-imprints in the calorimetry at CERN LHC” Zhen Liu told The Daily Galaxy, “we can significantly expand our knowledge of Higgs decays into long-lived particles. Global efforts in the next generation of Higgs factories, such will be fully geared toward exploring these intriguing possibilities centered around the Higgs gateway. These Higgs factories will include the International Linear Collider (ILC) under consideration in Japan and the Compact Linear Collider (CLIC) at CERN, while the other two are circular: the Future Circular Collider (FCC-ee) at CERN and the Circular Electron Positron Collider (CEPC) in China.
“If the particle is there, we just have to find a way to dig it out,” Wang said. “Usually, the key is finding the question to ask.”