Reflecting on null results in High Energy Physics

[hyksos]

TL;DR Summary

What restrictions do null results place on theories?

For nine years, a discrepancy of the charge radius of a proton was a tantalizing hint at physics beyond the Standard Model. Recent experiments at York U in Toronto have shown that the discrepancy in the proton radius was likely due to a measurement error. Once again, High-Energy-Physics finds itself in a cul-de-sac of null results.

This an appropriate time to reflect on how HEP has been suffering from a spate of null results for the last 20 years. Pure theory in physics during the 1990s gave rise to a laundry list of hypothesese which I will list here :

• Deviations deriving from the electron dipole moment, that would cause electrons to be "squashed" in one direction.
• Baryon number violation. Predicted from symmetry violation in exotic electro-weak theories.
• Large radiative corrections to the Higgs mass. (likely SUSY)
• Signs of supersymmetric particles predicted by SUSY.
• Occasional nuclear decays due to very rare interactions of dark matter particles with nuclei in large underground water tanks.
• Deviations in gravitational waves that would be telltale signs of extra dimensions of space.

Now in 2019, all of the above predictions have come under experimental test. But in every case, nothing was observed. The universe spit null results at us. None of these avenues of investigation into physics beyond the SM have yielded the fruit promised to us in the 1990s.

Nima Arkani-Hamed has responded to the spate of null results as having the job of "explaining zero". Arkani-Hamed has also said that while null results are unsatisfying, they often focus our attention on a much more restricted class of theories.

What sorts of theories and ideas is particle physics restricted to now?

Your thoughts?

 

[AndyW]

As a scientist in the field of particle physics, I can understand the frustration and disappointment that comes with a string of null results. However, I also believe that these results are just as valuable as positive ones, as they can help us narrow down and refine our theories.

In terms of the theories and ideas that particle physics is now restricted to, I would say that we are still exploring a wide range of possibilities. While the specific hypotheses listed in the forum post may have been disproven, there are still many other avenues of investigation that have not yet been explored.

For example, the search for dark matter, which has been ongoing for decades, is still a major focus in particle physics. The existence of dark matter has been inferred from its gravitational effects, but its exact nature is still unknown. This leaves room for a variety of theories and ideas to be explored and tested.

Additionally, the discovery of the Higgs boson in 2012 has opened up new opportunities to study the properties of this particle and its interactions with other particles. This could potentially lead to new theories and ideas about the fundamental nature of the universe.

Furthermore, the recent advancements in technology and experimental techniques have allowed us to probe deeper into the subatomic world than ever before. This could potentially lead to new discoveries and insights that could guide our understanding of particle physics in the future.

In summary, while the spate of null results may seem discouraging, I believe that it is important to view them as opportunities for further exploration and refinement of our theories. The field of particle physics is still wide open, and I am confident that with continued research and experimentation, we will eventually uncover new and exciting insights into the fundamental nature of the universe.