One of those experiments, as discussed by a collaboration of particle physicists in a new paper published in the journal Physical Review D, could focus on why the universe is dominated by matter and not antimatter, one of the most enduring mysteries in modern physics.
And the focus of the study? Yes, the infamous Higgs boson may be at least partially to blame for our universe’s matter-antimatter asymmetry.
When the universe began, right at the ignition of the Big Bang some 13.75 billion years ago, particles of matter and antimatter should have been generated in equal numbers. As all Star Trek fans know, should matter and antimatter meet, total annihilation occurs. Therefore, if equal quantities of matter and antimatter were generated, there should be no matter or antimatter left in the universe — instead, the universe would have remained as a soup of energy where matter (or antimatter) could not form.
But as we look around us, although tiny quantities of antimatter can be found, the universe is obviously filled with matter. So the question is: Why did matter win out?
Since the discovery of the Higgs boson, physicists have been studying its characteristics in the LHC data. As the particle accelerator collides protons inside its building-sized detectors, a few isolated Higgs bosons are generated. But they don’t last long in isolation; they quickly break down — or “decay” — into other subatomic particles and energy.
The Higgs boson itself is not directly observed by the LHC, instead it is the Higgs’ decay particles that are detected. After billions and billions of collisions, eventually a strong enough signal was generated that, in 2012, LHC scientists were able to triumphantly announce the Higgs boson’s historic discovery. This was significant, not only because it was observational evidence of a boson that was theorized back in the 1960s, but because it appeared to be a Standard Model Higgs at a theorized energy of 125 GeV/c2 — basically the final and elusive piece of the Standard Model that describes all particles and forces (except gravity) in nature.
Now there could be a twist to the Higgs story.
As the Higgs field is intimately tied to matter, physicists are understandably asking whether the Higgs could be the driving force of the matter-antimatter unbalance, which specifically focuses on a phenomenon known as charge-parity (CP) violation.
“Searching for CP violation at the LHC is tricky,” said Matt Dolan, a research associate at the Department of Energy’s SLAC National Accelerator Laboratory at Stanford University, Calif. “We’ve just started to look into the properties of the Higgs, and the experiments must be very carefully designed if we are to improve our understanding of how the Higgs behaves under different conditions.”
In its most basic sense, CP violation means that nature treats a particle (matter) and its antiparticle (antimatter) differently, a phenomenon that SLAC’s BaBar experiment studies. When the universe was born, there must have been a CP violation as nature somehow treats matter differently from antimatter, so there is some physical subtlety that we haven’t yet understood.
As detailed in a SLAC news release, physicists first need to confirm the Higgs fits into the Standard Model, then they need to take extremely detailed measurements of the decay products and the jets of energy the Higgs decay generates. One particular type of Higgs decay centers on the production of two tau particles — leptons that are basically massive electrons — where the remaining energy of the proton-proton collisions sprays into two defined jets.
Read more at Discovery News
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