At the time of writing, physicists are excited by the possible detection of the Higgs boson. After analyzing data from the Large Hadron Collider (LHC) at CERN, Europe’s High Energy Physics Laboratory near Geneva, Switzerland, the particle signal – thought to give mass to other particles – was observed in the region of 125 gigaelectronvolts (GeV). has gone.
It is too early to say whether these promising signals will be confirmed, but if they are, many would consider it a validation of the Standard Model of particle physics.
Other data have given previous indirect indications that the Higgs boson probably weighs less than 150 GeV, and a possible CERN observation would be consistent with that. But I am a contrarian. I would argue that whether or not the Higgs boson exists, we already know that there must be physics beyond the Standard Model. Let’s consider the possibilities.
avert fall
One option is that evidence from the LHC would be confirmed, and that a standard-model Higgs boson exists in the mass range of less than 130 GeV. Experimentalists would say that this is where theorists were asking them to see everything, which is true. But there is a catch. Within the Standard Model, it is possible to calculate the minimum energy state of the universe.
If the Higgs is lighter, this calculation predicts a state of lowest energy, unlike our current universe. This implies that our universe is in some other, unstable state that will eventually transition to a state of its lowest energy—in the next week, or a few billion years, we may go down the cosmological tubes.
Some physicists say that this disturbing conclusion is the result of taking the theory too seriously, and that when we come to it we should find the Higgs and cross this bridge. But it is worrying. The only way to produce a more stable model would be to add new particles to the Standard Model, in which case it is predicted by the principles of supersymmetry.
avert a blow
What if the LHC evidence is not confirmed? In principle, there are other options. For example, there is another range of potential Higgs masses, above 600 GeV, where CERN has yet to look. In this case, we should go beyond the Standard Model for two reasons. First, physicists have found and measured the mass and other properties of the W and Z bosons, which mediate the fundamental weak nuclear forces.
Theoretical interpretation of these measurements seems to indicate that the Higgs must weigh less than 150 GeV. If the Higgs is indeed very heavy, it can only be resolved by adding a number of new interactions between known particles. Second, the interactions between the heavy Higgs bosons appear to be infinite at high energies. Clearly this setback should be avoided, but understanding how is beyond the Standard Model.
Could there be a lighter Higgs boson, hidden between 130 GeV and 600 GeV? The LHC has ejected a standard Higgs boson in this region, but it is still possible that the Higgs may lurk there, if its interactions with other particles are not as predicted by the Standard Model. One possibility could be that it has some additional, invisible mode of decay into particles, such as through pairs of weakly interacting particles of dark matter.
Another possibility is that its decays are normal, but the rate at which other particles collide to produce the Higgs boson is suppressed. Make such an adjustment, however, and the Standard Model is no longer a computable theory; And the whole point of the Higgs is to make the Standard Model computable. The only way to fix this would be to add new particles to the mix, such as a massive spin-a particle, to accomplish the work that the Higgs had to do.
These problems would be particularly severe in the absence of the Higgs boson. Physicists have to explain, in a way that is both computable and consistent with existing measurements, how and why symmetry breaks between different species of Standard-Model particles—only a few particles in the Standard Model have mass.
The Higgs is supposed to force the symmetric standard-model equations to have these asymmetric solutions. It would be unfair to break the internal symmetry of the equations themselves, since it is not known how to calculate sensible results in such a case.
Alternatively, one can break the symmetry of solutions to standard-model equations by setting specific boundary conditions. Just as a physicist’s description of how a washing line hangs between two walls depends not only on the properties of the line, but also on its attachment to the walls, so also the description of bosons at their edges. depends on the behavior. universe.
Our current description of a four-dimensional universe does not have edges in this sense, but additional dimensions, possibly curled into smaller spaces so that no experiment has yet been able to detect them, may provide suitable limits: the Standard Model. Beyond physics indeed.