The Standard Model of Particle Physics is Brilliant and Completely Flawed
Each time physicists discover a new particle, the Standard Model gets one step closer to becoming a Super Model.
We always talk about whether the newcomer fits in, stands out or matches the predictions of the model. Everything is linked to this “Bible of quantum physics”.
The standard model is not mystical, however. It is purely, beautifully mathematical.
Yet for all its predictive power, it’s not perfect – it can’t explain gravity, dark matter, or dark energy. The real goal of physicists who smash particles is to smash it.
Only by finding new particles that weren’t predicted by the standard model and can’t fit into it will we move to a new, improved model – one that doesn’t have big gaps. where gravity and the dark parts of physics should be.
The standard model explained
Forty years ago, scientists squeezed everything they knew about quantum physics into one massive equation – the Standard Model of particle physics.
If you can follow the math, the standard model is a stunning job. It’s like a practical guide to the particles and forces that operate on the tiny quantum scale – including all the atoms that make up people, plants, planets and stars.
(Fortunately for the non-physicists among us, it also comes in a handy chart – and our hands-on video above.)
The big problem with the Standard Model is that it doesn’t just describe already known particles, like the electron and quarks that make up atoms.
He did something far more important: he also predicted new particles, including the Higgs boson.
Testing predictions is at the heart of science, and every single particle predicted by the Standard Model has since been discovered. The Higgs was the last to be found, in 2012.
But while it’s undeniably brilliant, no one ever claimed the standard model was perfect.
It’s not broken, but it needs to be fixed…
The most obvious flaw of the Standard Model was there from the start – it could never account for gravity, the force that rules at the macro scale. This is not the fault of the standard model; quantum theory and Einstein’s theory of gravity simply don’t work together.
But gravity isn’t the only thing the model lacks.
The Standard Model also cannot account for the dark matter and dark energy that make up 95% of the universe.
And the weirdest thing of all is that he comes right out and says the universe shouldn’t exist – at least not as it is. The model predicts that matter and antimatter should have been produced in equal amounts at the birth of the universe and annihilated immediately afterwards, leaving behind a huge sea of light.
Luckily, that didn’t exactly go as planned either; there is matter everywhere, including you and me.
Some of the other shortcomings of the Standard Model are on a much smaller, galactic scale.
One of the best-known problems is that he predicts that a family of particles – neutrinos – should have zero mass. But as the recipients of the 2015 Nobel Prize in Physics can attest, these ridiculously small particles that travel at near-light speed have very small, but not zero, masses.
And in the decades since its appearance, theoretical physicists have tossed around a pile of possible additions to the model, trying to account for the things it can’t explain.
These mainly involve new particles much heavier than the known quarks, leptons and bosons. In supersymmetry, the best-known “upgrade” of the model, each particle has a much heavier partner, called a sparticle, which helps fill in the current gaps.
Theories are great, but if we want to know which, if any, of the various Standard Model upgrades are correct, we really need to find new particles. And that’s where particle accelerators come in.
If you break it they will come
Particle accelerators smash tiny bits of matter — ranging from electrons to whole atoms — at nearly the speed of light. When this happens, the energy from the collision can be converted into matter. (Einstein’s E=mc2 tells us that mass and energy are two sides of the same coin).
And if there’s enough energy, it can form a heavier particle than we’ve ever observed.
Heavy particles made in colliders are usually unstable – they only exist for an incredibly short time before breaking up into lighter, more stable pieces. But these tell-tale remnants are exactly what physicists are looking for in experiments at particle accelerators all over the world.
So far, the new particles have not been able to “break” the Standard Model; they keep opening new chapters.
The hunt for the next supermodel in science
Knowing the mass and energy of these particles will favor some of the new theoretical additions and eliminate others.
The more new particles we find, the more limited the scope for improvement of the model.
Any new heavy particle found will result in new characters in the Standard Model equation and the start of an additional row or column in the accompanying table. This “standard plus model” could account for neutrino mass, the antimatter/matter problem, dark matter and dark energy.
But the consideration of gravity won’t happen without completely switching to a new theory – a theory that accounts for all known particles and phenomena as well as the current model, but which can also work with gravity.
And the theories of quantum gravity will not be validated anytime soon by particle accelerators. The energies required to test them are far beyond the reach of even the greatest atom smashers.