When are you going to find something, is one of the most frequently asked questions I am asked.
We talk a lot about progress in discovering new particles. Studying a heavy particle can help us see the underlying physical processes. It's easy to explain the value of the discovery to the public.
A series of precise measurements of already known particles and processes have threatened to shake up physics. It is time to start discussing the implications of the higher energy and intensity of the LHC.
New particles are one of two ways particle physics has proceeded. The other is to make very precise measurements that test the predictions of theories and look for deviations from what is expected.
The early evidence for Einstein's theory of general relativity came from discovering small deviations in the apparent positions of stars.
Particles obey a successful theory called quantum mechanics. The theory shows that particles too big to be made directly in a lab collision can still have an effect on what other particles do. It's difficult to explain the effects to the public.
Recent results hint at unexplained new physics beyond the standard model. The particle known as a beauty quark is more likely to fall into an electron than into a nucleus. The standard model suggests that new particles or forces of nature may influence the process.
The decay of the top quarks does happen at the same rate for electrons and muons as it does for the electrons and muons.
The Muon g-2 experiment at the US's Fermilab has recently made very precise studies of how muons interact with surrounding objects. It found a small but significant deviation from some theoretical predictions, again suggesting that unknown forces or particles may be at work.
A measurement of the mass of a fundamental particle called the W boson, which carries the weak nuclear force that governs radioactive decay, is the latest surprising result. After many years of data taking and analysis, the experiment at Fermilab suggests that it is heavier than theory predicts, deviating by an amount that would not happen by chance in more than a million experiments. It is possible that undiscovered particles are adding to its mass.
This also disagrees with some lower-precision measurements from the LHC presented in this study and this one.
The evidence seems to be growing that some new physics is needed to explain the effects.
There will be many new mechanisms proposed to explain these observations. Many will look at different forms of supersymmetry. The idea is that there are more fundamental particles in the standard model than we thought. The field that gives fundamental particles their mass may be involved.
Others will use ideas such as technicolor, which implies that there are additional forces of nature, such as gravity, electromagnetism, and the weak and strong nuclear forces. Experiments will reveal the truth, which is good news for experimentalists.
The teams behind the new findings have been working on the problems for a long time. It is not disrespectful to note that these are very difficult to make. The standard model requires calculations where approximations have to be made. Depending on the level of approximation made, different theorists can predict slightly different rates of decay. Some of the new findings may fit with the standard model when we do more accurate calculations.
It could be that the researchers are using subtly different interpretations. It is important to check that the same level of approximation has been used in both cases.
These are two examples of sources ofsystematic uncertainty, and while all concerned do their best to quantify them, there can be unforeseen complications that under- or overestimate them.
The current results are still interesting and important. There are multiple pathways to a deeper understanding of the new physics that need to be explored.
There are still possibilities of new particles being made through rarer processes or hidden under the previous background that we have yet to uncover.
Roger Jones is the Head of Department at Lancaster University and the author of this article. The original article is worth a read.
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