When Will Fermilab Release Its Initial Muon g-2 Measurement?

  • #1
ohwilleke
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Summary:

Fermilab's E989 experiment, which is measuring the anomalous magnetic moment of the muon, was due to report its initial results in 2020 but didn't. Do we know when it will announce them?
Fermilab's E989 experiment is conducting the first precision measurement of the anomalous magnetic moment of the muon (muon g-2) since the Brookhaven lab did so fifteen years ago. It is currently collecting Run-3 data for this experiment, and said that it would be releasing preliminary Run-1 results in late 2020 at a September 2020 physics conference. See https://arxiv.org/abs/2009.07709

The discrepancy between the Brookhaven measurement and the theoretically predicted value of that measurement (which is a little more than three sigma) is one of the most important discrepancies between the Standard Model of Particle Physics and experiment. If the experimentally measured value in the Bookhaven experiment stayed the same, the result would be seven sigma proof of new physics. If the new measurement matched the theoretically predicted value, this would be a global measurements that would strongly suggest that the Standard Model is a complete and accurate description of low energy physics. So, everyone's dying to know what they've found (J-PARC's E34 experiment is also measuring the same thing, but its results won't be available for one to three more years, because Fermilab is just that awesome by comparison).

Well, it's the year 2021 now and no results have been released.

Does anyone know or have a good idea regarding what is going on and delaying the release of these results?

If the announcement that results would be released in late 2020 had been made in January 2020, the obvious conclusion would have been to blame COVID-19. But in the case of a planned late 2020 release stated in September of 2020, that doesn't seem like as likely an explanation.

For example, is there any reason to think that a particularly remarkable results is causing the scientists involved to delay releasing the results because they want to do an extra check of their accuracy first? Or, did some catastrophe that didn't make the news hit Fermilab?
 

Answers and Replies

  • #2
Vanadium 50
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That sounds a lot like a rant that science should be done on your schedule, not the scientists'.

When Will Fermilab Release Its Initial Muon g-2 Measurement?
  • It's not Fermilab. It's the collaboration.
  • The collaboration will release it when they are ready.
They have no incentive to release a result that isn't ready. They have no incentive to sit on a result that is and not make it public.

is there any reason to think that a particularly remarkable results is causing the scientists involved to delay releasing the results because they want to do an extra check of their accuracy first
You are accusing the collaboration of poor scientific and borderline unethical behavior. Got any evidence?
 
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  • #3
ChrisVer
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accusing the collaboration of poor scientific and borderline unethical behavior
Ehm, I disagree with this conclusion of yours. In my opinion, it is totally ethical and scientific to delay a publication to make sure you are confident in your results, rather than publishing something you are uncertain about. Scientific work needs its time, and a couple of months delays is not so rare (especially for precision measurements).

Now to the OP and regarding the rest, I doubt they can be answered if you are not associated with the collaboration to have internal information. And even if you are, I don't think you have the right to speak publicly about it. So you can only make wild guesses and that's not taking you anywhere. The only thing you can do is be highly confident (although not 100% as it involves humans) that when something comes out, it wouldn't be a mistake.

However, I would wonder, if the anomaly persists, would that mean definitely the presence of physics beyond the standard model, or would it mean something is missing in the calculations? It is something I hear often been said about the b-anomalies too.
 
  • #4
Vanadium 50
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, it is totally ethical and scientific to delay a publication to make sure you are confident in your results, rather than publishing something you are uncertain about.
I agree. But g-2 has stated many times that their experiment is blinded. And once you have unblinded, you're not allowed to then go back and fiddle with the analysis. Especially based on the outcome.
 
  • #5
ohwilleke
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I agree. But g-2 has stated many times that their experiment is blinded. And once you have unblinded, you're not allowed to then go back and fiddle with the analysis. Especially based on the outcome.
But, if the unblinded data reveals what looks like a goofy problem, like the one that caused the superluminal neutrino speed result from the OPERA experiment a while back, it wouldn't be improper to try to look for an explanation before publishing and to include that investigation in the final product. "Yes, our Run-1 raw data was off by a factor of 3% in a parts per million precision measurement, but we think we've identified the Xcel spreadsheet glitch that caused that problem." (I'm alluding to an incident like that in an Ethiopian ancient DNA paper a couple of years ago where that was discovered a few months after publication and resulted in a partial retraction and revision of one of the several key findings.)

Now to the OP and regarding the rest, I doubt they can be answered if you are not associated with the collaboration to have internal information. And even if you are, I don't think you have the right to speak publicly about it.
What I was mostly hoping for was that someone might have been aware of an authorized statement through some channel I am not privy to, not published in arXiv or at the collaboration website I located (which hadn't been updated since June 2020), that publication has been delayed until X date for Y reason. Physics Forums has lots of people who read Twitter feeds and blogs and hear unpublished conference presentations, etc. that I might not know about, from scientists who are involved in experiments like these, which is the kind of forum in which I wouldn't be surprised to see an announcement about something like this.

Once the collaboration publicly states an expected publication date and then doesn't deliver, it invites speculation that something is amiss. Best practices in PR (both in and out of science) is to make an announcement if that is going to happen, a revised estimate (possibly vague) and if possible, a statement of the often innocuous reason for the delay. At a minimum, something like an announcement on the collaboration website that: "We weren't able to publish Run-1 results in December 2020 as expected, but do expect to have published results sometime in 2021. This was due to unavoidable delays in the publication process."

Certainly, there are lots of reasons that announced publication dates get moved back. Some are innocuous, while others are interesting, either because they hint at something about the expected results, or because they tell outsiders something about the day to day reality of the scientific process unrelated to the results themselves.

For example, if the delay were due to delay in Congressional approval of the new fiscal year's appropriation bill that was funding the collaboration, or due to a major post-snow storm flood that delayed dozens of projects with apparatus at the same location, that would be interesting to know, and would expand familiarity with what life is like trying to lead a collaboration like this one.

Certainly, it would be commonplace for a collaboration to compel its members not to disclose the substance of what will be published prior to publication. But it would be considerably less common for a collaboration to prohibit its members from discussing the revised timing of a previously announced publication date target in a manner that does not disclose what the publication itself will contain, or to prohibit collaborators from discussing some intervening cause for a delay (e.g. maybe their supercomputer resources were pre-empted to do time sensitive COVID work, or a key investigator who has to approve the final product had to take a leave of absence due to a death or illness in the family or new child that was born prematurely or a revised spring semester academic calendar), even if the cause of the delay isn't something the the collaboration would want to put in a press release. There are things that are both not secret and also not something that somebody actively wants to broadcast to the world.
 
  • #6
Vanadium 50
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But, if ... <long train of evidence-free speculation and innuendo>
 
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  • #7
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I think you are seriously

a) overestimating and overstating the level of commitment anyone has made to definitely publish something in December 2020. I don‘t see a definitive publication date stated anywhere that could be officially corrected.

b) underestimating how little it takes to delay a publication, in particular with so many people involved, by weeks and months. (Probably especially if there is no external pressure like competing experiments etc.)
 
  • #8
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I've spent more time at Argonne than at Fermilab, but according to my understanding of history, all of the guys at one University of Chicago location allowed that the cadmium rods were raised exactly as Prof. Fermi, with his slide rule and mechanical pencil (Prof. Fermi sometimes would write interim results on his slide rule) directed ##-## anyway, I think that even though everyone in that room was brilliant, there may have been a local-to-there consensus that Enrico Fermi was the smartest man in the room ##-## according to history, there was no doubt that he was in charge of the experiment ##\dots##
 

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