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A strange new beast in the particle bestiary? Answered

Interesting article from the BBC website :-

A particle accelerator in the US has shown compelling hints of a never-before-seen particle, researchers say.  The find must be more fully confirmed, but researchers at the Tevatron are racing to work through existing data.  If proved, it will be a completely new, unanticipated particle; researchers say it cannot be the much sought-after Higgs boson.  It could also signal a new fundamental force of nature, and the most radical change in physics for decades.

The full article is HERE.


It's only a 3-sigma, vaguely Gaussian-looking bump, which shows up after a huge subtraction of "background." The putative "signal" only appears in CDF's data (they're one of two experiments at the Tevatron). If D0, the other experiment, sees the same signal, that will lend more credence to the result.

According to the BBC:

However, the result is at what is known as the "three-sigma" level of certainty; that means there is still about a tenth of a percent chance that the result is attributable to some statistical fluctuation in the data.

For a formal discovery, the level is traditionally taken to be five-sigma - or about a one-in-a-million chance that the "bump" is just a fluke. However, Dr Hooper said, the result comes from data taken at one of the Tevatron's two detectors, called CDF and DZero.

"Even without running the machine one more day, they have roughly twice as much data at one of the two experiments, and if you include... DZero, then you have four times as much," he told BBC News.

That means that confirming the result more fully is simply a matter of working through the numbers the team already have to hand. Further, the coming experimental run at the Large Hadron Collider (LHC) should provide even more data to confirm or refute the new particle - whatever it is.


Thanks for the expert view on this, Kelsey. I'm thinking it was one of those events which normally goes unreported but the Beeb has picked it up on a slow news day.

BTW, what is the feeling 'in the trade' on dark matter and dark energy?  Science is, of course, a best explanation based on proven knowledge, but DM and DE (from a non scientific viewpoint) has always seemed unsatisfactory to me.  Two terms proposed to resolve massive inaccuracies in the astrophysical equations, but with no hard evidence (i.e. observed rather than inferred) to support them.

Is there a feeling that there is an alternative explanation which hasn't been discovered yet?

Dark matter has a lot of "justification" in particle physics. Neutrinos have mass, so there is a contribution to the matter content from neutrinos (they don't solve the dark-matter problem, because they're too "hot", i.e., have too high velocities). The axion, hypothesized by Peccei and Quinn to solve the strong-CP problem, is an excellent candidate for a non-interacting dark-matter particle.

Dark energy is rather more problematic. You can start with an inflaton potential (very similar to the Higgs potential), and if you add a metastable plateau instead of a simple mexican-hat, then you can get something like inflation followed by "dark energy" expansion, but it requires a lot of fine tuning.

Does the fact that there is something vaguely uninformational about it in the news mean that there's something new, or that it takes THREE DAYS to write about it in a newpaper???

Thank you for posting this - interesting topic on which to hear news.

Whilst not directly relevant I thought you might like this: