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The Higgs rumor spreads again June 5, 2007

Posted by dorigo in Blogroll, internet, italian blogs, news, personal, physics, politics, science.

The recent  rumor about a possible MSSM Higgs signal, which made its way on electronic media starting from  a comment on this blog after having been passed mouth to ear for a while among HEP experimentalists, has now spread wide through blogs (for instance in Not Even Wrong , in the Arcadian Functor, in Charm & c. ( twice), in Asymptotia , in the Quantum Pontiff, in Bad Astronomy, and apologies to those I missed), online journals ( Slate, the Center for Science Writings), and the like. 

The tentative signal allegedly seen by the D-zero experiment at the Tevatron might be significant  – some unverified sources talk about 4- to 5-sigma deviations. But it might just as well (or certainly, if you ask yours truly) be a fluctuation, a incorrect modeling of multiple heavy flavor production backgrounds, or a combination of both effects.

We have already seen the very same propagation mechanism at work a few months ago, after blog posts commenting another tentative MSSM Higgs signal seen this time by CDF (on a different final state) made ripples in the web. Therefore, we are in the pleasant position of having a good shot at predicting the future, creating for ourselves the possibility to sit back and observe the predictable unpredictability of the propagation of information in this inordinate beginning of the twentyfirst century.

Let us learn from the past. It took about five weeks before the New Scientist published the story of the possible observation of Higgs decays to tau-lepton pairs and the alleged ensuing rumors that the particle could be seen – if it existed – in other datasets. From then on, things snowballed with a piece on the Economist and quite a few articles on daily and weekly newspapers of regional interest.

On that occasion, however, there was a rock-hard core of news to base the story on (or, as journalists would see it, to build the story around): the tau-lepton pair signal was public, had been presented at a international conference, and the CDF collaboration was standing behind it as a single man. In the present case, instead, the ripples in the blogosphere have started from nothing more than a rumor: we lack, in this case, of a real notitia criminis.

Will journalists manage to build the story around nothing this time ? I think so, because the topic is red-hot. LHC versus Tevatron, Europe vs the US, a multi-billion-dollar investment at risk of being left without anything else to discover. And more: the diffusion of scientific information in the 21st century, the loyalty of members of giant collaborations and the impossibility to keep things secret, the sociological implications when even larger collaborations at CERN will start publishing. Plus, of course, the physics issue: is the Standard Model alive ? Will Supersymmetry be found ? What does Witten say ? (The latter, admittedly, is more like something string theory novices would ask themselves than a meaningful question from a science writer.)

I have no idea how long it may take D-zero to produce a preliminary result from their multi-b analysis. I believe it will be ready for summer conferences, which means a time-scale of about six more weeks. Will science magazines be willing to wait ? Hmmm. I bet there already are a few investigations ongoing (but I swear I personally have not been contacted by the press yet). So my prediction is that this story is going to appear on printed paper at least somewhere , just in time to match the public release of D-zero findings – mid-July most probably. 

Eventually, though, this will bubble out as everything else. This prediction is much easier to make: I am convinced that the signal is an artifact even without having seen it, by just studying the previous paper by D-zero – but I admittedly base my idea on the belief that supersymmetry is a nice, bold, incorrect theory.

There remains to discuss whether all these rumors are good, bad, or irrelevant for the progress of science and the well-being of high-energy physics. My opinion ? Getting mediatic attention is good for science. And while it is true that crying wolf too many times gets the general public bored, funding agencies, however, know better. Hell, the committees are formed by smart people, not ordinary Joes who cannot distinguish an official result from their own fart, if you pardon my French. So I am not in the least moved by the anxiety of those stiff-necks that are ready to point their fingers at rumor-spreading as if it was the reason for their failure to get grants, rather than their ineptitude. Particle physics will out-live just as well their irrelevant contribution as the wild rumors they blame.


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[…] Higgs Boson. Unfortunately, this is not related to anything I do, but something I read one (e.g. here). I consider this interesting on several sides. First off, it is interesting where physics will end […]

3. Jeremy Manier - June 5, 2007

> I swear I personally have not been contacted by the press yet

Well… if you have a moment please drop me a line. Just in case there’s something here. 🙂

Jeremy Manier
Chicago Tribune

4. Kea - June 6, 2007

ROTFLOL! The phrase an incorrect modeling of multiple heavy flavor production backgrounds sounds really very plausible … if it’s not just a rumour and there actually is some kind of bump, which we have no way of determining, especially with the knowledge that SUSY partners will never be found … well, it could be something else I suppose … maybe Tommaso accidentally tripped on one of the cables …

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[…] The Higgs rumor spreads again The recent  rumor about a possible MSSM Higgs signal, which made its way on electronic media starting from  a […] […]

6. Tony Smith - June 6, 2007

Tommaso, with respect to such rumors as D0 seeing
“… a 5-sigma 4 b-jet event resonance at 180 GeV …”
you say
“… a SM Higgs cannot be seen at 180 GeV, for a number of reasons:
… the Higgs decay to bb is quite suppressed for this mass,
where the decays allowed are to WW and ZZ (close to 100%) …
… the cross section of H production in the SM at 180 GeV is very small, so at the Tevatron we would be unable to see it even with 10x more statistics, even combining information from different search channels. …”.

What about the Standard Model possibility that
at 180 GeV the Higgs mostly decays to Z Z
that 15% of the Z decays are b bbar
so that
maybe D0 could be seeing b bbar b bbar from
fast decay to H to Z Z and the fast decay of 15% of them to b bar b bar ?

As to production, could the structure of a composite Higgs model
enhance the cross section at 180 GeV beyond the minimal Standard Model value,
thus giving the Tevatron a chance to see such a composite SM 180 GeV Higgs ?

I suspect that there should be data analysis ways to tell such a 2-stage decay from a single-stage H to b bar b bar,
ways to check about whether composite Higgs could be involved,
with the present status of rumor information,
the situation does not seem clear to me,
although I think that the above suggestions may be naive, speculative, and possibly wrong,
I don’t see an easy way to rule them out without more details
about the D0 data.

I wish that details of the internal D0 discussions were publicly available so that interested physicists outside D0 could think about such things on a basis of data instead of rumor.

What would be wrong with input from outsiders,

other than fear of somebody outside (maybe you, Tommaso) explaining some things by using a line of thinking that the D0 insiders might have missed?

It seems to me that the wider pool of people you have looking at a problem, the more likely it is to be solved,
that closed access to data etc has no place in pure science,
only in military secrecy for weapons development.

Tony Smith

7. Tony Smith - June 6, 2007

In my previous message, instead of “the fast decay of 15% of them [ Z Z ] to b bar b bar”

I should have said
“the fast decay of 15% of each of the Z to b bar b bar, for a compound probability of a bit over 2% of b bbar b bar production”.

8. Tony Smith - June 6, 2007

Sorry for yet another typo. I should not have said “Z to b bar b bar”,
should have said
“Z to b bar”.
Sorry for that.
Tony Smith

9. dorigo - June 6, 2007

Hi Tony,

I exclude that a SM H decaying to ZZ-> bb bb (15% x 15% =0.0225 by BR alone, but actually much smaller fraction due to acceptances)
could be observed at the Tevatron. We are talking about a signal of less than one femtobarn here, immersed in a background of picobarns size (QCD g->bbbb, bbjj, bbcc with correct or incorrect b-tagging).

Moreover, D0 correctly looked for M_12 (mass of the two leading jets) when looking for a MSSM Higgs to b-bbar in the last published analysis. Making a 4-b mass would be silly given the impossibility to detect the SM ZZZZ signal, while to see a MSSM H->bb they just need tan(beta) to be large enough, even at 180 GeV.
So, if in a H(180)->ZZ->bbbb event you made the M_12 distribution, you would find a Z peak on top of a broad combinatorial background peaking at about 120 GeV. You would see nothing at 180 GeV, of course.

As for the SM with composite higgs, I think it is no longer the SM, and all the implications for BR and the like go off the board. In that case, I am unable to answer…


10. dorigo - June 6, 2007

Dear Jeremy,

as I said, I am not entitled to talking about a private D0 analysis. I am a member of CDF and CMS. I can talk to you about the Higgs boson in general and dissolve any doubts you may have, but only by representing myself. If I did, what I would say would not be different from what you may get from other sources on the net. As Gordon Watts, a member of D0, says in this instance, “I have very little or no authority” in this case.


11. dorigo - June 6, 2007

Kea, that’s right – I think it is something else, but I swear I never visited the D0 control room!


12. Chicago-Munich-Venice-Munich-Paris « A Quantum Diaries Survivor - June 6, 2007

[…] interested in other posts here about the recent rumors from Higgs searches, say for instance  this one or  this other […]

13. Namit Mahajan - June 6, 2007

Dear Tommaso,
What range or value of tan(beta) is required to be consistent with the rumoured signal? ie how large exactly is tan(beta)?

14. Tony Smith - June 6, 2007

Tommaso, with respect to rumors of D0 seeing
“… a 5-sigma 4 b-jet event resonance at 180 GeV …”
the possibility of “… a SM H decaying to ZZ-> bb bb (15% x 15% =0.0225 by BR alone …”,
you said
“… As for the SM with composite higgs, I think it is no longer the SM, and all the implications for BR and the like go off the board. …”.

So, if D0 is seeing such a rumored signal, and it is the Higgs at 180 GeV, then would it not be possible that it could have more than one reasonable physical interpretation, including but not limited to:
1 – MSSM with high tan beta
2 – composite Higgs as Tquark condensate
… etc …

When groups (such as D0) meet to consider releasing results, do they consider just releasing the data without physical interpretation, or do they hold back until they can get an internal consensus as to physical interpretation ?

It seems to me that releasing data sooner (with no physical interpretation) would be better,
if D0 waited until it reached a binding consensus about a physical interpretation (for example, a high tan beta MSSM Higgs)
would that not penalize people working on other possibilities (for example, composite Higgs people) ?

I agree with you that calculation of backgrounds for such a signal at Tevatron may be very difficult and that very good physicists could have errors in such calculations, and that a bet that the rumors are based on background calculation error is probably a safe bet,
the primary point I am trying to make is:
collaborations should concentrate on quickly releasing experimental data rather than trying to force themselves to reach consensus on physical interpretations.

Tony Smith

15. dorigo - June 6, 2007

Hi Tony,

indeed, D0 I think does as CDF: if the data is sound and the analysis also is, then they publish it sooner rather than later. However, at times the review process is long and tedious, and the likelihood of tediousness grows with the interest of the result.

I am quite sure that D0 sought for MSSM H and not for still more exotic models, but they might set limits to any model provided the model predicts a cross section and a branching ratio for the observable phenomenon.

I doubt D0 will spend a lot of time on the interpretation. They want to get there first as anybody else.


16. dorigo - June 6, 2007

Hi Namit,

I really do not know. I imagine it is largish, since at 180 GeV the cross section is small otherwise, and with only 2/fb one would not see a significant signal.


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[…] am really wondering about with the Higgs search rumor mill discussion (see e.g. here, here, here or here), is that these collaborations don’t care for attention in the media. I believe, there are […]

18. Namit Mahajan - June 7, 2007

Hi Tommaso,
A rough estimate shows that for 180 GeV m_A, to be consistent with the B_s –> mu mu rate, tan(beta) should be 25 or so (of course a little here and there is certainly possible!).
Is this value of tan(beta) OK to be consistent with the required cross-section for the rumoured signal? Or, if I may ask, what is the lowest value of tan(beta) you expect to be consistent with the signal in question – from what I can guess, should be around 50 or so. Is that correct?
Best, Namit

19. Tony Smith - June 7, 2007

Tommaso, you said that you are “… quite sure that D0 sought for MSSM H and not for still more exotic models, but they might set limits to any model provided the model predicts a cross section and a branching ratio for the observable phenomenon. …”.

Assuming that the rumored D0 signal turns out to be a real 180 GeV Higgs, do you think that consideration will be given to non-supersymmetric interpretations
such as
the composite Tquark condensate model of Hashimoto, Tanabashi, and Yamawaki,
who published in hep-ph/0311165 a prediction of a Higgs at 176-188 GeV ?

They used a T-quark condensate model in 8-dimensional spacetime with 4 compact dimensions. They said:

“… The idea of the top quark condensate explains naturally the large top mass of the order of the electroweak symmetry breaking (EWSB) scale. In … this idea often called the “top mode standard model” (TMSM), the scalar bound state of tbar-t plays the role of the Higgs boson in the SM. …
the SM gauge bosons and the third generation of quarks and leptons live in the … 8-dimensional bulk, while the first and second generations are confined in the … 4-dimensional Minkowski space-time …
… We predict masses of the top (m_t) and the Higgs (m_H) …
based on the renormalization group for the top Yukawa and Higgs quartic couplings with the compositeness conditions at the scale where the bulk top condenses …
for …[ Kaluza-Klein type ]… dimension… D=8 …
m_t = 172-175 GeV
m_H=176-188 GeV …”.

My fear is the the supersymmetry industry will seize the MSSM possibility and generate so much hype that non-supersymmetric alternatives will be ignored in follow-up theoretical research and analysis, even though the Hashimoto-Tanabashi-Yamawaki model is very concrete and predicted the 180 GeV Higgs mass.

Tony Smith

PS – I am posting a similar comment on the blog of Gordon Watts, because he is at D0. I hope that it is OK to do that.

20. dorigo - June 7, 2007

Namit, I am unable to answer your question other than saying the following: at 180 GeV the limit D0 expected to put on tan beta was higher than 100 with 1/fb of data (see graph in https://dorigo.wordpress.com/2007/05/28/i-want-to-know-about-the-multi-b-excess-too/ ).

So I think that a significant signal with twice more data may only be possible with a tan(beta) of the same order of magnitude, or with a completely revolutionized analysis. The latter is not impossible, but I find it hard to believe that one can gain more than a factor of three in sensitivity from an already well-done analysis. So we would be looking at a signal compatible with a quite large tan(beta). But this assumes several things we do not know about the analysis.


21. dorigo - June 7, 2007

Hi Tony,

thank you for your interesting comment.
To answer your question, I think that if a signal were seen, it would indeed be most likely attributed to a MSSM Higgs, because that theory is all the rage these days. That, despite the fact that one does not really know until one measures much more of the bosonic sector.


22. alpinekat - June 8, 2007

My understanding of high energy physics is only very basic, but I’m just wondering… If the Higgs doesn’t show up at LHC, will it still be worthwhile to look for it?

23. dorigo - June 9, 2007

Hi kat,

well, I think that if the LHC does not provide an observation of a Higgs boson, nor any explanation of the inner workings of the mechanism responsible for electroweak symmetry breaking -or if you want, the origin of mass- then it would be really hard to put together a stance for a new machine. So it might still be worthwhile to look for something else, but we might not be able to do it…

To answer your question from another point of view, if the LHC fails to find a higgs boson it means it is not there, so we might need to start looking for something quite different.


24. Andrew Foland - June 9, 2007

Hi Tommaso! (It’s been a while!)

1. Has D0 ever shown a Z->bb peak?
2. Are these types of events efficiently collected by straightforward high-pT triggers, or do they benefit substantially from b-triggers?


25. dorigo - June 9, 2007

Hi Andy,
nice to hear from you! Where have you been ? I’ll make a spires search.

To answer your questions, yes, D0 has made a preliminary Z0->bb signal public last year. It was about 1700 events, extracted by a technique using single and double tagging ratios in some fancy combination. You can see the signal discussed in https://dorigo.wordpress.com/2007/03/01/the-mssm-higgs-signal-buried-in-my-plot/ and links therein, or just go to the D0 public results page http://www-d0.fnal.gov/Run2Physics/WWW/results/higgs.htm (the result on Z->bb is down the list a bit).

I think the multijet sample used by D0 in their searches is collected by a trigger requiring three clusters, some Ht, and a global impact parameter condition at level 3. That, at least, was used in the bbb MSSM search made public last year. However that might have been improved recently.


26. alpinekat - June 12, 2007

Thanks for the explanation!

27. matt - June 18, 2007

Ironically enough, the blog saying that the media was hyping this out of proportion got linked by a story in Wired (http://www.wired.com/science/discoveries/news/2007/06/higgsboson)
I guess covering the coverage is how people will manage to report on nothing.

28. Andy Feehan - June 19, 2007

I’m an American artist living in Europe. I have only a layman’s knowledge of what you guys are doing, but I am sure you are doing the most exciting kind of science. Even so, it seems to me that your search will continue ad infinitum. It’s a mystery. If we could get to the bottom of it all, it would be both an insult to our minds and to god or whatever you want to call her.

I love this dictum, attributed to Nicolas of Cusa, but probably is much older: “Deus est sphaera infinita cujus centrum est ubique circumfrentia nusquam. “

29. dorigo - June 19, 2007

Hi Andy,

thanks for visiting. Yes, it is possible that physics will never solve the puzzle of the theory of everything. Current candidates, in fact, are like the Undead of 3rd category movies…

I however disagree with your statement that we would be insulting anything, our mind or our god, if we found the ultimate answer. First of all, I do think there is an answer. And second, I think it is both possible and necessary for mankind to try and find it. As Dante puts it, “Fatte non foste a viver come bruti, ma per seguir virtute e canoscenza”.


30. Andy Feehan - June 19, 2007

Hi, Dorigo,

I don’t wish to discourage anyone from searching for the theory of everything. I simply wonder if it isn’t likely that no matter how far we look, finding answers along the way, perhaps each answer will forever lead to another question. If it did not, would we not be disappointed?

It is in the best part of our nature to wonder. May we always follow virtue and knowledge.



31. Andy Feehan - July 24, 2007

Hi, Tomasso,

You guys are getting some good press. I read the NY Times article today, and I’m glad the author translated what you do into layman’s language. Good luck on the Quest.

32. dorigo - July 24, 2007

Hello Andy,

Dennis Overbye is an excellent science writer, and he understood that he needed to be careful… He interviewed several players and his article is indeed accurate and interesting.


33. dorigo - July 24, 2007

And I now realize I did not answer your former comment, now a month old. Well, yes, science works by letting us in a new room with new doors on the opposite end. We never seem to get to the bottom of it. But I, for one, would indeed like to see the bottom of it. If I knew everything about how the universe works, I think I could die with a smile.


34. Erik - July 25, 2007

Just curious if your role in spreading this rumour will have a negative impact on your scientific career. Will CDF and other collaborators be unwilling to accept you as a collaborator for fear that you will leak information on your blog?

There does seem to be something to the rumour. Every day we don’t hear something makes it more likely that the bump is real. If this turns out to be the case, there is little chance that it is the Higgs. A mass of 180 GeV is just too big. It’s much more likely to be something else, most likely one of the superpartners.

35. impunv - July 25, 2007

There is no Higgs. See my blog

Click on

Science blog

Political blog

for explanation. Ignore the politics unless you like nasty remarks about Bush.

36. dorigo - July 25, 2007


I did get some d0 folks upset by posting about it. Let’s say that they would be happy to deny me a position if I applied at their institution. But it does not stop there, because there are a lot of people out there who do not like what I have been doing. Some of them are influential physicists. I got some indirect hints that I should stop blogging altogether. But I think what I do is useful, interesting, and I like doing it, so the hell with that.

No, I disagree about the marking time argument – if nothing comes out during this summer (and it isn’t) at conferences, it was quite probably a wild rumor based on some first look at new data before taking into account some subtle bias. That is exactly why many think this “rumor spreading” is bad for science. I think it is not, but it is beyond the point.


37. MSSM Higgs at 160 GeV: one more piece of non-evidence « A Quantum Diaries Survivor - August 27, 2007

[…] I am too lazy to replicate all the links here, so if you want to dig in the issue please find all the required addresses in this more comprehensive summary . […]

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