Does the Higgs Boson Spell Doom for the Universe?
In 2012, the Large Hadron Collider (LHS) at the particle physics laboratory of CERN in Geneva, was confirmed to have found the long hypothesised Higgs Boson. This marked the end to one of the biggest and most expensive searches in the history of science. While this is extremely exciting, some believe that its existence may spell doom for the universe.
“If you use all the physics that we know now, and you do what you think is a straightforward calculation, it is bad news”, said Joseph Lykken, a theoretical physicist at Fermilab. He went on to say that “the universe we live in could be inherently unstable”. But what does the Higgs Boson do? Well, the Higgs Boson is the reason particles have mass they do. The Higgs particle that the LHC found, possessed a mass of roughly 126 GeV (‘giga electron volts’), which is a lot. Based on the data analysis thus far, this discovered particle is consistent with the Standard Model (this is the highly popular, accepted theory of particle physics). And so, the particle they found looks to be the Standard Model Higgs Boson, however, it may be that a more massive Higgs particle also exists. But where am I going with this?
Well, it appears to be the fact that this discovered particle is a Standard Model Higgs Boson, which could deem the universe as ultimately unstable. This is all to do with what is known as the “vacuum stability” of the Standard Model. One might imagine that in a vacuum, there is no matter. However, it is believed that a vacuum is actually infested with particle-antiparticle pairs that pop into existence, before briefly annihilating each other and disappearing again. It is the inherent uncertainty proposed by quantum mechanics that allows these spontaneous fluctuations. Provided they only exist for a very small instance of time, no laws of physics are violated. The Standard Model also says that for the vacuum of empty space to be stable, we should be living at a minimum of potential energy. Or put more simply, most things should end up resting in a place of lowest energy. A good analogy is that of a ball in a valley. The ball seeks to be at the lowest point of the valley. To move it from this point requires energy. In the case of the universe, the point of lowest potential energy would be the Higgs potential, which correlates to the value stated earlier: 126 GeV. If our valley isn’t the lowest one around, our universe could end.
Benjamin Allanach, a physicist from the University of Cambridge, explained that “the shape of the Higgs potential is determined precisely by the Higgs mass”. The observed 126 GeV mass seems to imply “that the universe does not exist in a lowest possible energy state”, but rather, it is positioned in a “slightly unusual place”. For a Higgs Boson of mass 126 GeV, we could be in a local minimum, which is not the global minimum. The graph below shows a very simplified version of what is meant by this.
Thus, from our perspective, we may appear to be at the lowest point. However, if we were to somehow get to the other side, we could fall much, much lower. Classically, this would not pose a threat as it would not be possible to travel between valleys. The emphasis is on the world classically, as in quantum mechanics, this becomes a possibility: quantum tunnelling. As a result, in the future our universe could “spontaneously” and “randomly” tunnel through to a lower minimum, with “potentially catastrophic consequences”, Allanach said. However, it is not all doom and gloom. Physicists from the University of Rome and the Autonomous University of Barcelona have calculated the broad implication of the Higgs mass. It is now known with a large degree of confidence that our vacuum is on the unstable side. Furthermore, they were able to calculate its decay lifetime, which turned out to be far larger than the present age of the universe. Thus, most theoretical physicists do not worry about the destruction of the universe, as the effects of the instability implied by the Higgs Boson will not manifest anytime soon.
Originally published at http://thephysicsfootprint.wordpress.com on January 20, 2022.
