Thursday, August 23, 2012

Strange claims about a new \(38\MeV\) boson

Originally posted on August 22nd in the morning

In February 2012, Eef van Beveren and George Rupp released a provocative preprint based on their February 2011 work
Material evidence of a 38 MeV boson
in which they argued there is some evidence in the data from BABAR, CDF, CMD-2, CB-ELSA, and COMPASS experiments that there could exist a new particle whose mass is just \(38\MeV\) or so. This new hypothetical beast was called \(E(38)\) and it primarily manifested itself in some "apparently too regular" periodicities (by \(76\MeV\): they're supposed to be caused by interference effects) in some quantities measured by BABAR and others.

In April, four people from the COMPASS collaboration responded that all the patterns that van Beveren and Rupp were intrigued by were due to \(\pi^0\), \(\eta\), and secondary interactions inside the COMPASS spectrometer.

Days later, the original two authors argued that the COMPASS' critique is inconsistent with its own simulations. You could still believe that van Beveren and Rupp were excessively excited and they are probably wrong.

However, things would get somewhat less clear two days ago when a group from Dubna, Russia (and Moscow, Armenia, and Moldova) published their
Observation of the \(E(38)\)-boson
which looked, like some experiments previously referred to, the diphoton spectrum and it does claim it's there!

The format or genre of this paper looks strange to my "Westernized eyes" – for example, it apparently avoids the standard quantities in such papers such as confidence levels – but there are various graphs that do suggest rather clear bumps near the mass of the conjectured new particle.

Those things are either complete errors in the experiments, or due to some overlooked known physics, or... evidence for a new particle – a new \(Z'\)-boson, a new Higgs-like particle, or perhaps less likely, an axion – at a completely shocking place. The mass of this new particle would be in between the down-quark mass and the strange-quark mass; we have surely thought that we understood everything over there and there could have been no ghost and dragons in that mass interval.

Note that there has been at least one remotely similar bizarre claim about new bosons near an \(\MeV\). David Tucker-Smith and Itay Yavin postulated a new \(1\MeV\)-like boson to explain anomalies in the muonic Hydrogen Lamb shift. However, their paper (see Figure 1) really makes a prediction that the new force carrier's mass shouldn't differ from \(1\MeV\) by more than a factor of two or so. So these two weird proposals probably can't be "unified".

Of course that I would bet against each of them – but I could also be wrong which is why you may want to check the evidence yourself.

See also Physics Stack Exchange and blog entries by Chris Austin, Tommaso Dorigo, and Barry Adams.


  1. Figure 8 has a weird shape. It's not the typical Lorenzian that one sees from a genuine particle. If it's real, I'd guess that there are actually two particles but the experiment doesn't have the resolution to separate them.

  2. I always like it to be informed about such "preliminary but potentially exciting results" even if the probability that these bumps go away is high ... That is one of the many things I like TRF for :-).

    Conversely, Matt Strassler refuses even to write and talk about such things and more generally, he now even discourages (in particular non expert) readers from busying themself trying to learn more about BSM physics until something of it is discovered at the LHC ... :-/. He says there is no point for non experts in trying to understand and follow such things at present (in some comments). This makes me unhappy :-(

  3. Dear Dilaton, may I respectfully comment? Like you, I enjoy reading both TRF and Professor Matt Strassler (although I never comment at the latter). I believe that both Doctor Motl and Professor Strassler (did I mention that he's a professor) do great work communicating theoretical physics, at all levels, to the public. Each has their strengths, and each may have a weakness or two (perhaps Strassler is a bit stuffy, perhaps he is not the world's fastest typist and is therefore constrained in his capacity to respond on his weblog). It is true that Prof. Strassler has been the target of some criticism from Dr. Motl. Assuming that 100 percent of that criticism is on point, nonetheless I have a hunch there is much, much more that they agree upon. I also believe that Dr. Motl would not hesitate a heartbeat to jump to Prof. Strassler's defense if he found himself attacked by some annoying publicity hound, crackpot or troll king. Forgive me for rambling on, I just thought I'd mention that.

  4. Dear Dilaton, be sure I feel much of your emotions equally.

    In some or many cases, I would agree with MS that it is not really possible to understand certain technical points without a sufficiently deep technical background. I just don't believe it's the case of most of these discussions about potential new particles etc. In principle, these are extremely straightforward things.

  5. Thanks Lumo and Eugene for your answers ;-)

    I usually liked to read Prof. Matt Strasslers physics articles a lot and there used to be some interesting discussions, Q&As, etc in the comments too. But a few weeks ago his site has become just horrible. The comment sections are polluted with abominable trolls, including the trollmaster himself, etc who spit and spat on the Milner Prize, string theory of course, and fundamental physics :-(.

    I was so happy about the Milner Prize for example, but now the sourballs have made my cheerful feelings about it completetly go away.
    And since I have some kind of a background in some theoretical physics topics, about two years ago it has become my best hobby trying to learn by myself about things like QFT, particle physics, and fundamental physics generally even at a slightly technical (demystified) level since I'm no longer satisfied by equation free popular texts. And I've discovered that something in my mind perfectly and strongly resonates with the way of thinking theoretical physicists have as I first learned about it by Lenny Susskind's lectures for example. Trying to follow in realtime "what is shaking" in these fields in the internet and observing that my understanding and accordingly my appreciation of it increases was exciting and a lot of fun for me.

    But now Matt Strassler's comments have completely discouraged me from carrying on my best hobby and at present clicking his site and observing that it is full of trolls that attack him and everybody else who really cares for fundamental physics just makes me sad and unhappy and I'm deeply in sorrow about the future of fundamental physics (which I've learned to like and appreciate lot).

    At least here on TRF I can read about cool physics without getting annoyed and upset by tons of trolls and sourballs who want to destroy it. But I am painfully aware that they are there outside this nice place ... :-(

  6. I admit I like - even am a sucker for - all kinds of safe enough surprises. But, as far as such happenings in HEP goes, I prefer to lie low and not delight too much until they are evaluated positively, then memo'ed, by LM. :>

  7. Hi all -
    I think I might have accidentally contributed to this latest flare - I wrote a comment agreeing with Dilaton and Dude over at MS's site and accused the main troll of misrepresenting facts and then this blog about string theory and laymen etc... appeared. Oops. As I said in a post many moons ago, you guys have convinced me Smoit has to be taken with a grain of salt. I guess all I'd like to add is that while of course its obviously true that laymen can't know all the details or truly understand fine technical arguments without a physics education, this fact is not limited to physics. There is almost no area of human endeavor in which laymen can know all the details, and in almost everything we do we trust experts while still asking them to explain stuff to us. I have to deal with it daily in my field of medicine (I promise, to really understand and treat any complicated medical issue without help from a doctor, it is really necessary to go to medical school) but it happens in any field - have any of you ever really sat down and talked to a farmer or a carpenter or a sailor? Or a painter, for that matter? The amount of things they consider when they are doing their "thing" is astounding - things that never occur to laymen. Nevertheless, as you state in your response to Dilaton Dr. (is it doctor?) Motl, even laymen can understand basics and get excited about new discoveries. And especially in the case of string theory, where we now have one group of physicists essentially accusing another group of fraud in order to control grant money and professorships, I'd say laymen are being dragged in, since we're the ones being asked to pay the salaries.

  8. Hi Andy,

    thanks for having been among the few remaining reasonable people over there ... ;-)

  9. Tobias SchlüterAug 23, 2012, 3:07:00 PM

    Since I wrote the bulk of COMPASS's reply, I was of course interested to see this paper. In my opinion, it is quite clear the the bumps are created by the shape of their background (which they never explain). In practically all of their plots the enhancement near 38 MeV is accompanied by a depletion range either at lower or at higher masses, which tells me that using a slightly steeper (or shallower) background there would not be a bump.

  10. MW ≈ 28 MeV; MZ ≈ 32 MeV in the gedakenwelt of Quigg and Shrock: