SUSY and GUTs all but eliminated by latest ACME experiment

In summary, the new experiment places an upper limit on the electron's electric dipole moment at 9.4x10-29 e cm, an order of magnitude improvement over the previous measurement. This eliminates many models of the universe that were based on the assumption of naturalness.
  • #1
MrRobotoToo
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I'm surprised no one has posted about this yet, so I guess I'll take it upon myself to post the link, even though I have no real expertise on the subject. The ACME collaboration had the results of their latest measurement of the electron's EDM published in Nature today. They place an upper limit of 9.4X10-29 e cm, an order of magnitude improvement over the previous measurement. According to the chart below, this value eliminates many BSM models. I've also included a couple of pedagogical videos from the ACME group. RIP 'naturalness'.

PW-2013-11-147-Johnston-edm-second.jpg


 

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  • #2
The relevant constraint analysis which that chart is based on is :
https://arxiv.org/abs/1612.08090

It should be noted that the subclass of models that are being considered and ruled out are rather extreme. So significant caveats and loopholes exist in the general case for all models considered. The plots in the original paper are more indicative of the reach of this experiment. Still this experiment quite significantly constrains the relevant theory spaces for model builders.
 
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  • #3
Haelfix said:
It should be noted that the subclass of models that are being considered and ruled out are rather extreme

Which makes the title highly misleading.
 
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  • #4
I am puzzled by the upper limit value of 9.4X10-29 e cm.
Within the Standard Model of elementary particle physics, such a dipole is predicted to be non-zero but very small, at most 10−38 e·cm.

If I am understanding correctly what I am reading, the new upper limit value is 10 orders of magnitudes larger than the upper limit quoted in Wikipedia. Now I know that Wikipedia's reputation in the PF is not on a par with authoritative journals like Nature, but this extreme difference is quite puzzling.
 
  • #5
Buzz Bloom said:
If I am understanding correctly what I am reading, the new upper limit value is 10 orders of magnitudes larger

The above is an experimental observation

Buzz Bloom said:
than the upper limit quoted in Wikipedia

This a standard model theoretical prediction. Some Beyond the Standard Model theories make larger predictions.
 
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  • #6
Buzz Bloom said:
I am puzzled by the upper limit value of 9.4X10-29 e cm.
Within the Standard Model of elementary particle physics, such a dipole is predicted to be non-zero but very small, at most 10−38 e·cm.

If I am understanding correctly what I am reading, the new upper limit value is 10 orders of magnitudes larger than the upper limit quoted in Wikipedia. Now I know that Wikipedia's reputation in the PF is not on a par with authoritative journals like Nature, but this extreme difference is quite puzzling.
I goofed on the upper limit: I quoted the old one--the new one is actually an order of magnitude smaller (by 'smaller' I mean that it's approximately one-tenth the value that I quoted). You can find it in the linked paper. For some reason I'm not able to edit my original post. Also, if I could, I would retitle the thread "Natural SUSY all but eliminated..." to make it more accurate.
 

What is SUSY and GUTs?

SUSY (Supersymmetry) and GUTs (Grand Unified Theories) are theoretical physics models that attempt to unify the forces of nature, including gravity, into a single framework. These models predict the existence of new particles that have not yet been observed.

What is the latest ACME experiment?

The latest ACME (Advanced Cold Molecule Electron Electric Dipole Moment) experiment is a scientific study conducted at Harvard University that aimed to measure the electric dipole moment of the electron, which could provide evidence for the existence of new physics beyond the Standard Model.

What does it mean for SUSY and GUTs to be "eliminated"?

In this context, "eliminated" means that the results of the ACME experiment do not support the predictions made by SUSY and GUTs. This means that these models are less likely to accurately describe our understanding of the universe.

Why is the elimination of SUSY and GUTs significant?

SUSY and GUTs have been popular theories in physics for decades, but their predictions have not yet been confirmed by experimental evidence. The elimination of these models by the ACME experiment means that scientists will need to explore other theories and approaches to understanding the fundamental forces of nature.

What are the implications of the ACME experiment for future research?

The results of the ACME experiment will likely lead to further investigations and refinements of existing theories, as well as the development of new theories that can better explain the fundamental forces of nature. It also highlights the importance of experimental evidence in validating theoretical models in physics.

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