“Up to now all measurements match the predictions of the Standard Model.”
Are we about to enter a new era in physics? We might very well be if recent results from the Large Hadron Collider (LHC) in Switzerland, hinting at activity beyond the Standard Model of physics, are confirmed.
Physicists working at the LHC particle accelerator at the European Organization for Nuclear Research (CERN) saw traces of physics beyond the standard model of particle physics. This indication emerged from the latest analysis of data collected by the LHCb (Large Hadron Collider beauty) experiment in 2011 and 2012.
Currently, the Standard Model is the best explanation we have for how the universe works and how it’s held together. However, there are also large discrepancies in the model, including the fact that it does not account for gravity. This is the reason why scientists have spent decades trying to find signs of any activity that the standard model can’t explain — and now they finally might have.
Shortly after starting the analysis, an anomaly was discovered surrounding a particle called a B meson. These mesons are composed of a light quark, which we can find in protons and neutrons that form matter all around us, as well as a heavy beauty antiquark, which can be created in the LHC collider.
Since the particles are made up of pairs of quarks and antiquarks, they are unstable and decay rapidly. According to the standard model, B mesons should decay at very specific angles and frequencies. However, predictions are not matching up with what has been seen in the LHC experiments.
“Up to now all measurements match the predictions of the Standard Model. However, we know that the Standard Model cannot explain all the features of the Universe,” said lead researcher Mariusz Witek, from the Institute of Nuclear Physics of the Polish Academy of Sciences, in a press release.
“It doesn’t predict the masses of particles or tell us why fermions are organized in three families. How did the dominance of matter over antimatter in the universe come about? What is dark matter? Those questions remain unanswered. What's more, the force we all experience every day, gravity, isn’t even included in the model,” Witek continued.
Most of the research at the LHC has been concentrated on the search for the Higgs boson, determining the differences between matter and antimatter, and testing quark-gluon plasma. However, more attention is now being focused on detecting new elementary particles beyond the Standard Model.
New experiments are trying to see such particles directly, but the mass of the particles may be too high to be produced at the energies of the LHC accelerator. If that is the case, the only way of discovering new physics would be to observe the influence they have on phenomena we can observe at lower energies. For example, the influence could manifest itself by modifying the angle and frequency of the decay of beauty mesons.
Luckily, a new technique developed by physicists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Kraków, was able to show that not only did B mesons in 2011 decay at an angle that wasn’t predicted by the Standard Model, the same thing also happened in 2012.
The researchers have made it clear that this is not a discovery — there has to be more data before they can say if what they observed is real.
Now, what could be the reason for the observed anomalies? The most popular hypothesis is the existence of a new intermediate Z-prime boson (Z’), not predicted by the Standard Model, involved in the decay of B mesons.
If they can figure out what the anomalies are, we will be closer to unlocking some of the mysteries in the Universe. We just have to be patient.
“Just like it is with a good movie: everybody wonders what’s going to happen in the end, and nobody wants to wait for it,” said Witek.