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    Did Atlas Just See The Higgs ?
    By Tommaso Dorigo | April 22nd 2011 05:50 AM | 70 comments | Print | E-mail | Track Comments
    About Tommaso

    I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson...

    View Tommaso's Profile
    Note: updated list of links at the bottom.

    (Older Note:
    Bet on this signal! See at the bottom of the article! Odds are two to one in your favour now!)

    (Older note
    : Update at the bottom.)

    It seems I am late on this one -an internal note by the Atlas collaboration seems to contain the discovery of a bump in the diphoton mass distribution from data collected in 2010 and 2011. They find a signal that seems consistent, in mass and resolution, with what one would expect from a Higgs decay, if the Higgs were sitting at 115 GeV, the value at which LEP II found some hint (a 1.7 standard deviation signal) before being shut down in 2001.

    Since I cannot distribute information I do not possess, let me speculate on the information that has been distributed elsewhere already.

    • I think the signal is false, for a few reasons:
      •  It is not statistically compelling; the ATLAS authors (note that this is an internal document we are discussing, so while it is ATLAS data we cannot treat the result as backed off by the collaboration) claim in their abstract a local significance of 4 standard deviations, and then proceed to estimate the overall significance by accounting for a "look elsewhere effect" in the mass spectrum they examine. This comes from the fact that the bump could have appeared anywhere in the region of mass they analyzed, so it must be a trials factor of the order of a factor 20 increase in p-value, changing 4 standard deviations into something like 3.7.  But this neglects to account for the fact that there are many other places where similar bumps could have appeared and made it to the headlines but did not. I estimate the derating factor due to this "multiple search" by at least a factor of 1000 more with respect to what they claim, so their p-value is at least 1000-fold underestimated. This puts it well below the 3-sigma level.
      • the width seems what ATLAS expects to obtain for a narrow state, but this depends on how they apply their cuts, looser selections finding larger widths -a clear indication that something is not right.
      • the cross section is way too large for a narrow state. The SM Higgs would have a cross section thirty times smaller.
      • The large production rate fights with the Tevatron bounds, which exclude such states at cross sections not too much above the standard model (x1.5). One could argue that a particle with anomalously large coupling to photon pairs could elude those limits, which for the specific gamma-gamma final state are instead 20 times larger, and thus would allow the ATLAS signal... barely. But then, let us look at the CDF and DZERO results... See below.
      • In principle, the larger LHC energy could allow the "turning on" of the new process by one or two mechanisms. One is if this new particle is produced together with some other body, which is massive enough to make the production at the Tevatron disfavoured. But the ATLAS Higgs bid is for isolated diphotons with little else in the event, so this interpretation is at least on shaky ground. The other method might be if the new particle were produced by some diffractive mechanism, which would require a very special kinematic range, accessible at the LHC but not at the Tevatron. I find it rather weird too.
    • I think this will never make the light of a ATLAS public document: in fact, new data is pouring in very quickly, and CMS will not sit and wait either. So I think that the signal will disappear soon in ATLAS, and that CMS will internally show their competitors that they do not see anything similar...
    Ok, now that I dumped my first reactions, while being prevented from showing any mass distribution here, let me discuss a bit more what else exists -the Tevatron data.

    CDF

    First of all, CDF. CDF published recently a search for H->gamma gamma, where they analyzed 7 inverse femtobarns of collisions (that's seven thousand inverse picobarns, or over 110 times the data analyzed by the ATLAS experimenters).

    CDF looked for diphotons in four different combinations: central-central pairs, central-forward pairs, and CC and CP pairs where one photon is reconstructed by its conversion into an electron-positron pair. This happens when the photon crosses the strong electromagnetic field of a heavy nucleus in the detector: the CDF inner tracker contains silicon that can do this trick, but never mind -the electron and positron arising from the conversion can be reconstructed just as well as the photon. The four mass distributions that CDF finds are shown below.



    As you can see, if anything CDF sees some hint of a signal above backgrounds at 120 GeV, not 115; the "signal" is however totally insignificant: the red thing they add to these plots is the amount of signal they can exclude at 120 GeV compared to the data in each figure. Note also that the 115 GeV region is, if anything, depleted of events. There is no chance that the electromagnetic energy scale is wrong by 5%... The calibration of the CDF electromagnetic calorimeter is way more precise than that, so if you were thinking that the above figures could in some way get along well with a 115 GeV bump in ATLAS data, thing better.

     In the end CDF produces a upper limit on the signal cross section, shown below. As you see, the limit is above expectations (from data in hand and analysis technology) at 120 GeV, but it is in line with predictions at 115, where a signal 14 times larger than the SM is excluded.

    Maybe a couple of words should be spent on this plot: the horizontal axis shows the unknown Higgs mass; the vertical one the ratio between production ratio and SM prediction. A limit going below 1.0 on the y axis would exclude the corresponding Higgs mass on the x axis. Here we are not excluding anything because the curve stays between 10 and 30 times the predicted SM rate. The band is just showing the range of possible results that the experiment was expecting to find before actually looking at the data.

    DZERO

    DZERO also searched for diphoton resonances, and I discussed the matter with many details in a recent post. They recently cast the search also into one for "fermiophobic" higgs bosons, but the method and results are directly translated into ones for the plain Higgs to gamma gamma. But let us consider the standard search instead, detailed here.

    The mass distribution of diphoton pairs in 8.2 inverse femtobarns of their Run II data is shown above, together with background predictions (coloured histograms) and a 50 times larger than usual Higgs boson sitting at 115 GeV. No signal is apparent in the data, and they use this to set limits, which are shown below. Note that at 115 GeV DZERO excludes a SM Higgs with rate 20 times larger than the SM prediction. The DZERO data seems to have fluctuated 1.5 standard deviations up in that region.


    In conclusions, we can say the following:

    • CDF and DZERO together exclude a SM Higgs with production rates 1.5 times the prediction and above; this includes all possible decay modes studied.
    • If considering only the diphoton decay mode, bounds are looser: CDF excludes a rate of 14 times the SM prediction and above; DZERO excludes rates of 20 times the SM prediction and above.
    • CDF sees no excess at all at 115 GeV; DZERO sees some upward fluke, at the level of 1.5 standard deviations.
    • Both experiments would have seen with certainty a signal with a rate of 30 times the SM, as an anomalous enhancement at the level of three standard deviations or so.

    Other Resources on this topic

    Finally, since I think this topic will remain hot for a while, I will place here links to other sites which discuss the matter. For the time being we have the usual suspects:


    More coming...

    Update: a reader of this blog, PtrSlv2, pointed out in the blog of Resonaances that the authors of the ATLAS study are actually physicists from Wisconsin, and include Prof. Wu, who was among those less happy of the decommissioning of LEP II at the time when they were claiming a possible Higgs signal at 115 GeV. So maybe these guys have been looking for some comfirmation of the 115 GeV Higgs all along... Check out this article for details.

    Update: I cannot avoid commenting further here upon realizing that some of you do believe that the signal is genuine (see Lubos comment for instance). I have a different opinion, but I realize that anybody is entitled to his or her opinion -especially on such a fast-moving subject. In any case my comment is the following: in 2009 I was invited to the World Conference of Science Journalists, where discussing "Blogs, Big Physics, and Breaking News" in the glorious Westminster Hall (which seats over 2000, although my audience was admittedly much smaller) I made a very precise prediction on the Higgs boson, namely that the first we would hear about it would be in a blog comment. It seems that this is a perfect dry run for the prediction, validating it fully. Indeed, this being the Higgs or not, my prediction was valid ;-)

    (Addendum: here are two quotes from the transcript of my talk:
    "So who will have the news about the higgs boson, which is this handsome particle which was hypothesized more than 40 years ago, which fixes everything -well, not everything but many things about the subatomic world ? I think it will be announced many times. This has already started happening. It started in 2001 at CERN, and then it is going on..."
    And later I conclude the talk with this:
    "And the Higgs boson will be announced several times before it is actually there, and it might come out from anonymous comments."
    Yep - right on the money. Hmm I should stop saying I was right, it's becoming a habit. It does not make one too popular!)

    In any case, let me throw this in the water for Lubos or other believers here: I bet $1000 with whomever has a name and a reputation in particle physics (this is a necessary specification, because I need to be sure that the person taking the bet will honor it) that the signal is not due to Higgs boson decays. Details to be fixed. So be the first and take the bet!! If these are four standard deviations, it's a winning bet, isn't it ? The 4-sigmas quoted by the paper mean that the probability that this is NOT a new particle is ridiculously small, right ? (wink, wink).

    I realize the above highlighted text might be taken to mean that I believe this is a signal, but of something else. No, I am willing to bet that this is NO NEW PARTICLE. Clear enough ?

    Update on the bet: Okay, since a reader pointed out in the comments thread that the note starts with a quite startling statement, I changed my evaluation on the whole story. I am now twice as convinced that the bump is a fake, and that the four authors look too enthusiastic for me to appear as rigorous particle physicists. I will offer $1000 if a new resonance is confirmed at 115 GeV in the diphoton final state with, say, 10 times more data than analyzed in the paper we are discussing (this makes it about 700/pb, which will be collected in a few more months). If, on the other hand, no new such particle is confirmed by the time the experiments collect 10 times more data, I will receive $500.

    Any takers ? Use the comments thread and remember, you must use your real name and be prepared to pay if you lose.

    Comments

    Anna told me the same thing about Wu. I am also worried that her background increases her chances of seeing strange things near 115 GeV even if they are not there.

    But I would still lean towards the belief that this 115 GeV news is genuine.

    Tommaso: As a particle physicist and member of CDF and CMS you should know better than to propagate or even discuss leaked internal documents from any experiment. Such leaking is bad for all large experiments as it corrupts the internal review process and it will force the experiments to adopt policies that make internal dissemination and discussion of results much more difficult. That hurts all of us. Even if the "cat is out of the bag" anyone in particle physics or any field of science that wishes to preserve the integrity of that science should simply ignore the leak until it becomes a public result or disappears.

    my 0.02$

    Brian,
    Do you really think that the further analysis of the data and the internal review process of the ATLAS collaboration is going to be flummoxed by Tommaso's speculations here? Then experimental particle physics would be in a sad state of affairs indeed - and as long as he is expressing cautious pessimism and is not writing sensationalist stuff, this will certainly not make the reactions of the press etc worse.

    Hi Tommaso,

    The customary title would be Dr. Wu. It seems to me that extending every courtesy is important in this context.

    Seth

    I would say Dr. Dorigo should probably refer to "Professor Wu", but I agree with your sentiment, Dr. Zenz.

    dorigo
    I agree with you two 100%. My English is not perfect and when I am pressed with time (such as in this case) I sometimes fail to catch these mistakes.

    Best,
    T.
    Hank
    If I write something, I use the AP stylebook method, so the first time I refer to them I use their full name and title and then after that just their last time.   90% of the members of the site are PhDs and 99% of the people we write about are, so using Dr., much less Professor, each time would make the reading ridiculous.   If they don't have a PhD I just use name and position, no Mr. or Mrs.
    I agree pretty much, but if I recall correctly there was a discussion about that quite some time ago (so long I'm not sure if I'm not confusing something), but I think the upshot was that things written on prominent blogs about people have a chance of ending up in other media, and will show up on search engines for quite some time when researching the subject on the web, and therefore it would make sense to use a more formal address just to make sure It gets picked up correctly...

    Hank
    Indeed, that's why I use the AP method.  They are a world leader in news so if they use a format, it is acceptable to practically everyone.   Most scientists have a handy bio so even if theirs is 70 words long, the first time I discuss them I will write, Professor Tentpeg Shelterhalf, astrophysicist and chair of the physics department at University of Malaysia.  After that it is acceptable to just write "Shelterhalf says..."

    Dr. Dorigo (I didn't call him Tommaso since the comment thread is on showing respect for education and experience, wasn't that nice??) is writing about peers so his style will be looser. It's his blog, after all, he can write Prof. Wu if he has time or Sau Lan or whatever.  It is unlikely the public will suffer a huge credibility drop in physics if physicists use familiar terms for each other.   If anything, it feels more conversational.
    The Stand-Up Physicist
    How exciting! I cannot take you up on that bet for 2 reasons: one, I don't met your criteria, and two, I would want to take your side of the bet :-)
    Tommaso, could it be possible that after a long time using Monte Carlo programs you have become a compulsive gambler?

    dorigo
    Hah Vegas, nice one.
    I am not a compulsive gambler... I am trying to make money in a safe and fun way, out of gullible individuals! :D
    Cheers,
    T.
    ROFL!! Are all Italian physicists this funny?

    -drl

    Hank
    Funny unless you lose the bet.  NO ONE messes with Italians and their money.  Knees get broken.
    T. the first line in the note (which is very short) reads:
    It is the purpose of this Note to report the first experimental observation at the Large Hadron Collider
    (LHC) of the Higgs particle

    That's startling! It is a very bold sentence which no one would write unless he has a very solid ground to base it on.

    dorigo
    It is so startling that it speaks volumes of the credibility of the whole work!

    Okay, given this, I am willing to change the odds of my bet. I will now pay $1000 if a new particle is causing this bump, but receive only $500 if no new observation of a 115 GeV new particle is conclusively reported by the LHC experiments, say by the time they get 10 times more data.

    Cheers,
    T.
    I, too, believe that it will take some time, probably a year, to publish this result IF it continues to show itself. Ironically, a paper on which this analysis is based has never found its way into the arxiv!
    The paper is titled: "Production of isolated Higgs particle at the Large Hadron Collider, Physics Letters B 683 (2010) 354–357"
    Although I am not an ATLAS member, I think I cannot say more about this.

    About the bet; well, I wont bet now, I am not an expert as yourself :)

    Congratulations to @CERN for LHC breaking @Tevatron peak luminosity record!

    Seriously, since yesterday I've been thinking on the usefulness of being too harsh on people who have accepted to work within a collaboration - which means that the rest of the collaboration will, most probably, protect them from publishing something absolutely untrustworthy... Well, I haven't reached a conclusion yet and I understand that things like the bet target the gullible rather than the researcher, but still, when I read comments on Peter's post asking for someone to actually _leak_ the paper, I get nervous.
    Hell, you don't need to be a particle physicist, a plumber would get annoyed if the client criticized every movement he does with a screwdriver before the work is finished - even more if he took a wrong decision, finally decided to not implement it, and then he learnt that the client was telling the whole neighbourhood what a loser he is because of that momentary decision. (Yes, the public is the client.)
    I really hope that the next Higgs announcement made by an anonymoys commenter on a blog will not be one denounced by its collaboration within the next hours...

    Hank
    I did like "But, since spreading well-sourced rumors is more or less in the mission statement of this blog, I think I’ll promote this to its own posting" on Woit's piece.   I generally think the audience there (and here) is pretty smart and the occasional times the mass media takes something and runs with it are rare enough that talking about these things is more benefit than harm - but tulp makes a good point in detailing how few occupations or trades criticize the methodology before the work is done so I imagine ATLAS would rather be without the headaches.
    Dear Tommaso,

    a question from a non-professional dummy relating to the decay width of Higgs which should be smaller than 10^(-2) GeV in the mass region considered -say from the figure 4 of htttp://pdg.lbl.gov/2010/reviews/rpp2010-rev-higgs-boson.pdf . This is quite a small number as compared to the width of the peak like structure at 120 GeV appearing in D0 data measured in GeVs, which you represent as an example about bump which you reject.

    What is the contribution of the measurement uncertainties to the decay width- say that coming from the uncertainty in the measurement of gamma energies. If it is of order GeV meaning 1 per cent uncertainty in the measurement of gamma energy or even .1 GeV, how the experimentalists can conclude that Higgs candidate with decay width below 10^(-2) GeV is in question? Is this just an assumption?

    Matti Pitkanen

    dorigo
    Hi Matti,

    *all* of the observed width of a reconstructed H->gamma gamma peak at 115 GeV come from the resolution of the EM calorimeter.

    On the other hand, if the cross section is larger than the SM prediction, there is no reason to believe that the width is the same. Actually, it would be quite odd if the xs was larger and the width remained the same, because width and xs are related directly (through the Higgs couplings to fermions and bosons). In other words, to produce more Higgs bosons, they need to copule more to the initial state. But if they do, they also decay often into them. If, however, you only see the decay into gamma gamma, you must assume that it is highly enhanced with respect to the other possible decay modes. This means that the width must be larger.

    Best,
    T.
    ...There is no chance that the electromagnetic energy scale is wrong by 5%... The calibration of the CDF electromagnetic calorimeter is way more precise than that, so if you were thinking that the above figures could in some way get along well with a 115 GeV bump in ATLAS data, thin[k] better...

    Might it be possible/reasonable that the calibration of the ATLAS electromagnetic energy scale is off by -5%, so the bump they see at 115 GeV might actually be near 120 GeV, and in better alignment with the CDF bump that way?

    dorigo
    No.

    ATLAS measured Z->ee decays and the energy scale of the EM calorimeter is certainly better than 1%. I do not even bother to look at their recent papers... I know they must have of the order of 10 thousand such decays already studied. This means an error on the average mass position of less than one tenth of a GeV; and there are other calibration lines (the W for instance). If you want to, please check the number yourself.

    Cheers,
    T.
    Actually I was not asking about the energy scale or whether 115 and 120 GeV bumps could correspond to the same particle candidate.

    I was asking (as a dummy non-professional) whether the width of the bump due to measurement uncertainties for gamma energies allows to conclude anything about the actual decay width of the particle candidate. In particular, can one really deduce from the data that the decay width is indeed that predicted for Higgs, which is below 10^(-2) GeV and sounds quite small.

    From 115 GeV mass the determination of the actual decay width would allow less that .01 per cent relative errors in the measurement of gamma energies. If not, then the interpretation as photo-philic Higgs is just a guess motivated by theoretical prejudices.

    dorigo
    No, the width of a new signal must be determined with very bad accuracy, I think. And in any case we will never be able to measure directly the width into gamma-gamma, because it is two orders of magnitude smaller than the resolution.

    Cheers,
    T.
    Regarding the trial factor, this is certainly a test for the (already observed) excess seen in ALEPH by this group in the 4-jet channel at 114 GeV. No it wasn't a discovery and the significance decreased when combined with the other 3 LEP2 experiments, but the 4-jet excess in ALEPH stands.

    Thus, there is no trial factor, this is verification of an existing anomaly.

    dorigo
    Bob, there still is a trials factor, even if you are trying to verify an existing signal. It is not easy to explain, but in short, Minuit will try to use the freedom to move the peak a little bit in order to make the most of the degree of freedom (the floating mass). Only a strictly fixed mass (and width) fit can be claimed to have no trials factor involved. But that's not what was done here.

    Cheers,
    T.
    The mass is precisely known because it is at the edge of the kinematic limit of LEP2. The width is much less than detector resolution so is irrelevant. So, I still claim there is essentially no trial factor. Sure you can massage the location of the peak by ~1-2 GeV but this is not a huge trial factor, it's within detector resolution, essentially.

    I can't say what was done here as there is no paper (accessible to me) explaining what was done... :-/ I'm only pointing out what I would do given the ALEPH excess seen by this group. If their significance is this large and they did include a trial factor, it is even bigger news. But it is reasonable and correct that they did not include one.

    dorigo
    NO, you are mistaken. There is still a trials factor, and not necessarily very small. In fact, it is linearly dependent on the significance of the peak.

    Read for instance the recent paper by Gross and Vitells,
    http://arxiv.org/abs/1005.1891

    Best,
    T.
    I read your link and sorry, I disagree. Their arguments hold only when the width Gamma > range. For this possible signal, the experimental resolution dominates in both cases and is ~1-2 GeV in both cases, and the range is the width of the ALEPH signal, ~ 1-2 GeV, because it's at the kinematic threshold. Therefore, any trial factor is O(1). In fact I don't need to use minuit at all. Just make a window around the ALEPH signal corresponding to the resolution, and ask how many events are in the bin. Then it's simple Poisson statistics with no trail factor.

    Regarding "Update on the bet". You just want to have more time to collect this amount of money, don't You?

    Reading about re-doing analysis with more data, I always wonder, how long it takes to run an existing analysis on a new dataset. Is it measured hours? Or days? Or weeks?
    And what is taking most of the time? Reading all event data from storage, or the actual computations?

    Hi, as a CDF graduate student I can say it is measured in weeks. When you add new data sets, you first have to measure all the scale factors for several Monte-Carlo simulated events to real data events, i.e. the ratio in efficiency measured in simulated vs data evets: reconstruction for each charged lepton category, identifying jets to originate from bottom quarks, measuring the way jets originating from light quarks (u,d,c) or gluons can be incorrectly identified to originate from bottom quarks, trigger efficiencies, and so on, as well as systematic uncertainties for all these quantities. Without these you can not make the simulation match your data in the control regions of the analysis. After you do this, then you turn on your machinery once more, but this can take you several more weeks. You look at the background control plots and check carefully that they look fine and that you do not see funny bumps due to the new data or your new scale factor measurements. After that is done, you compute your limits, which can take up to a week on many supercomputers simultaneously.

    Tomasso, do you mean "fake" as in "hoax", or just as in not real?

    -drl

    dorigo
    I am not used to use the word "fake" as a substitute of "hoax", so without having to read back all I wrote above I can safely say I mean not real.

    Cheers,
    T.
    OK well "fake" is the verb that describes what one does to set up a "hoax", in English. "Fake" denotes an act of intention, while "false" just means wrong.

    -drl

    Since it won't last long on Peter's blog, I'll mention it here, since it is rather juicy information - such goings on in physics!! Quote:

    "No matter what the answers are, this leak shows that there are some internal problems within the Atlas collaboration. Apparently, ATLAS is led by a Queen (F.G) supported by a strong ‘old boys club’ of politicians. All the positions of responsibility are held by people close to the Queen or incompetent people who she can control easily. New people, but well connected to the management, can be appointed to key positions in ATLAS even before doing any service work for the collaboration. This has certainly got many people angry, and some of them have simply left ATLAS. "

    ROFL!! It's a soap opera!

    -drl

    On Peter Woit's blog a 22 April 2011 comment by Visitor
    (I saw no substantive discussion on Peter's blog about it)
    said:

    "This is likely trigger effect.
    If the have any trigger cuts around 110-120 GeV,
    this is threshold behaviour of not very well simulated trigger.
    ATLAS is famous for its approximations in MC,
    when they are using average efficiencies
    for various kinds of particles across large eta-phi areas
    instead of full detailed MC.
    So, it is possible to gain whatever bump you want
    in the areas near the trigger thresholds –
    they just didn’t simulate them properly."

    Tommaso,
    could you comment on the remark by Visitor
    about trigger effect ?

    Tony

    The Atlas trigger cut on Et is at 15 GeV. See their paper in first paragraph describing Data samples: http://cdsweb.cern.ch/record/1336758/files/ATLAS-CONF-2011-025.pdf?versi...

    As a result, the Atlas group might see a "bump" at a lower mass range, but it would not be due to an excess of events at that point, but rather a depletion of events below that value due to their 15 GeV trigger cut on each photon. This point in the mass distribution would be closer to 30 GeV, not 115 GeV though. Their trigger Et cut would have to be near 50 GeV or more for this to be seen near 115. If they see excess at 115 then, it would not due to a trigger effect. Tommaso can confirm this or correct ths, however...

    dorigo
    Yes I can. It's rubbish.

    Triggers on photons are very well understood. No way you can get a peak at 80-90 GeV and a decreasing background, and then a enhancement at 115 GeV. I know it since I saw the limit on H->gamma gamma that ATLAS published for Moriond.

    Cheers,
    T.
    Hi Tommaso,

    A nice post and yet nothing here that would on its own have me to wager either way if I were so inclined (which I’m not saying I am). Therefore I would ask if you’re confident this not being evidence of the Higgs resultant of, (a:) you thinking a convincing result should have been initially stronger, or (b:) it showed up in the wrong energy range, or (c:) rather that you consider the Higgs itself nonexistent to begin with?

    Best,

    Phil

    Hi Tommasso,

    I also find the name of the experimental apparatus and project being called Atlas sort of ironic in this instance. That is from your inference as to what thus far been presented would be consistent with the results being made as to appear to be what most researchers want. That is this could be like saying what they’ve found is that “Atlas Shrugged” rather than a demonstration of its power. Not that I’m totally in line with Ayn Rand’s philosophy, yet I do agree that when general expectation becomes what creative people are forced to comply with, both discovery and innovation can’t help but suffer.

    "A creative man is motivated by the desire to achieve, not by the desire to beat others."
    “The man who lets a leader prescribe his course is a wreck being towed to the scrap heap.”


    — Ayn Rand

    Best,

    Phil

    Can anyone tell, on the basis of information leaked so far (or on the basis of information in the note, if you're an insider), how many logged 115-GeV events might be behind this claim? The abstract says there are 63.5 inverse picobarns of data. Along with knowledge of the standard-model prediction for Higgs-to-diphoton decay, and the assertion in the note that the event rate is thirty times larger than expectation, that should be enough to figure it out...

    Why not just wait for a word from ATLAS? I mean what do we gain by learing rumors early when those are going to burst like bubbles?

    dorigo
    Hi anon,

    perfectly legitimate question. What do we learn ?

    I think we are giving to people interested in frontier research new things to think on and new reasons for excitement. If you are a rock climbing enthusiast you would like to know abount failed attempts at climbing a new peak. There is nothing despicable in reporting it, despite the fact that the person failing the climb might have preferred to keep silent on it...

    More specifically, we learn that the process of furthering our understanding of fundamental physics is difficult and filled with traps and roads that lead nowhere.

    Instead, I never for a minute bought the argument that we are "overhyping" things and that this can lead to media fatigue. I think that those who argue this way have not understood the way information works in the web 2.0 era.

    Cheers,
    T.
    According to this graph, the SM Higgs production cross section at sqrt(s) = 7 TeV for a 120 GeV Higgs is about 5 pb, so in 63.5 per pb we would expect about 318 Higgses to be produced if its mass is around 120 GeV. According to Jester only about 0.2 percent of Higgses decay this way, so according to the SM there would be about 0.64 H -> 2 gamma decays. Wu et al say the event rate is 30 times this, so they are claiming to have found about 19 H -> 2 gamma events.

    Vladimir Kalitvianski
    I will not bet on this signal.

    When you observe something via a certain pattern, you may find the phenomena that do not exist. Watch, for example, this white noise video:

     http://www.youtube.com/watch?v=Qeh1tSp20BA&feature=related

    Normally it is what a TV shows when there is no signal. You may see rings rotating clockwise, rain falling, people rushing on a stock exchange floor, etc. You have to tune your recognition filter to see something and you will find it.

    Concerning Higgs, it does not exist, in my humble opinion. It is a patch of a failing theoretical (gauge, massless) construction. Why should it exists?
    "this neglects to account for the fact that there are many other places where similar bumps could have appeared and made it to the headlines but did not. I estimate the derating factor due to this "multiple search" by at least a factor of 1000 more with respect to what they claim, so their p-value is at least 1000-fold underestimated. This puts it well below the 3-sigma level."

    True. Very, very true.

    So Tommaso when you in CDF publish a di-jet paper with a bump in a random plot in a random location and you claim that it has a 3-sigma significance you obviously took your de-rating factor into account, did you ? Was it a 5-sigma effect without it ?

    The only thing that is more pathetic than a guy who is prepared to sign a paper with a 3-sigma bump is a guy who then is ranting and raving against a 4-sigma bump discussed in an internal document of a competing experiment. How about making bets about your own papers being wrong rather than internal documents of other experiments.

    So how about it Tommaso, are you prepared to bet 1000$ that the ridiculous 3-sigma bump in your CDF paper is new physics ? If not, shut up.

    "So how about it Tommaso, are you prepared to bet 1000$ that the ridiculous 3-sigma bump in your CDF paper is new physics ? If not, shut up."

    I think Tommaso made very clear that he thinks CDF bump is most probably mis-modelling. If you were not able to read that far or have problems understanding written text, then shut up.

    So Tommaso must feel like a real jerk now when the paper he co-authored is being portrayed as evidence for new physics by theoreticians and the media.....

    The problem is that if Tommaso would have taken his own advice (which is sensible) he would not have signed the CDF di-jet paper. Serious physicist do not write crap paper on 3-sigma bumps and then let the media run wild. That is bad for physics and bad for science.

    What makes it worse is that after publishing his own crap bump paper he his now ranting and raving about a document he has not even seen. Using very good arguments against it but arguments that he should have applied to his own paper first if he wanted to keep some of his credibility. There is only one word for it: hypocrisy !

    dorigo
    Hi allan,

    I would not call rants my comments. I try to inform the reader of the reasons why this signal is probably not anything new, with all the knowledge I can throw at it. Then, for those still convinced, I offer a bet.

    As for signing or not papers with similar claims: The Wjj resonance can be bet on as well. I offer it four to one: 1000$ for me, 100 for you. Want to take it ? The reason why odds are more in your favour is that I know more of that signal, that's all.

    About the look-elsewhere effect: I have expressed my own opinion, which cannot always be metabolized by a full collaboration. In CMS they carry some weight, in CDF not any longer (I am not very much involved in the studies they do there).

    Cheers,
    T.
    it's called "look other-people-paper effect"
    :D

    D

    I guess it is called "word-blindness" you suffer. CDF did not claim new physics, 3-sigma is a good point to publish so theoristst and other community can start to work and speculate on possible mis-modellings and its reasons. Did you notice that deltaR plot in dijetmass paper, maybe it was difficult to read two plots next to each other, but that plot gave you hint of one possible source of mis-modelling.

    I repeat Tommasos observation which every grad student learn sooner or later: "this neglects to account for the fact that there are many other places where similar bumps could have appeared and made it to the headlines but did not. I estimate the derating factor due to this "multiple search" by at least a factor of 1000 more with respect to what they claim, so their p-value is at least 1000-fold underestimated. This puts it well below the 3-sigma level."

    The discovery of a 3-sigma fluctuation when you look through thousands of plots and you do not have a prediction that nails down in which plot to look and where to look has no statistical significance whatsoever. Nada. Zip. Zero.

    Why would you put theoreticians to work on fluctuations ? Don't they waste their lives on useless topics already.

    And let me give some quotes made in the media about this ridiculous paper:

    "If this signal is what we think it is, we could be on the verge of understanding why matter has mass, whereas light doesn't," said Professor Kenneth Lane, a theoretical physicist at Boston University. "We might be seeing the signal for a new kind of nuclear interaction which we have called 'technicolour'. This scenario basically replaces the Higgs boson." Professor Brian Cox of Manchester University said that if the results hold up to further analysis, and confirmation by a second experiment, "then it is RIP Standard Model".

    What it going to happen when people cry wolf in this way every time they see an insignificant fluctuation is that particle physics will loose all credibility.

    The CDF paper is a disgrace. And if it is accepted for publication that will show that the peer-review process with these large collaborations is broken.

    "CDF did not claim new physics"

    No of course not.

    That is why Fermilab has a video presentation entitled "CDF data peak causes excitement" on its front-page.

    And that is why newspapers all around the world have predicted the end of the Standard Model without CDF physicists making any protests.

    And that is why theoreticians are now busy publishing crap papers based on a crap CDF paper.

    But CDF physicists do not of course have any responsibility for this at all. "3-sigma is a good point to publish so theoristst and other community can start to work and speculate on possible mis-modellings and its reasons"
    Yeah right !

    Its called eating the cake and having it. One present the bump to the media as the end of the Standard Model but then write arguments on ones blog against it to cover ones ass.

    Moment,
    "Why would you put theoreticians to work on fluctuations ? Don't they waste their lives on useless topics already."

    "And that is why theoreticians are now busy publishing crap papers based on a crap CDF paper."

    Yes, it is like poetry, those thousands of plots, and always you see fluctuations. Of course, and Tommaso is quite good one to remind it us again and again.

    There is always discussion what is good hype, what is good publicity, what is bad, and guess what, no one will ever be on the same side.

    Personal view, if publicity makes young people excited about science, engineering, then there might be something good.

    "There is always discussion what is good hype, what is good publicity, what is bad, and guess what, no one will ever be on the same side."

    I think there are lots of physicists outside of CDF who agrees with me that one should not hype statistical fluctuations and use them to claim the end of the Standard Model.

    But the really funny thing in this case is that Tommaso had no problem in signing the CDF paper without any discussion in it about the lack of significance when you look at thousands of plots but when a rumor spreads about a 4-sigma bump in ATLAS he is immediately sure that it lacks all significance. Despite knowing nothing about the analysis.

    Are you unable to see the bizarre in his behaviour ?

    A 3-sigma bump in his data is interesting and deserves to be published. Including on the front-page of the Fermilab web site as exciting new physics. A rumor of a 4-sigma bump in someone else data is obviously a fluctuation.

    Just a minute, why is saying that you saw a 3-sigma bump, when you saw a 3-sigma bump, bad?
    I think that in some posts here the CDF 3-sigma was very explicitly rejected as a new discovery.
    On the other hand, starting a paper by saying you saw the first hint of Higgs in lhc is something else entirely...

    I have an idea: why don't you go tell Brian Cox, who made ridiculous statements about the CDF 3-sigma, to shut up? That way your 15 minutes of fame will stand a chance to be more intense.

    Well, like I said, those thousands of plots are just poetry. I dont remember seeing jet4 angle vs lepton to be a discovery plot, ie, at the end there are not thousands of plots that pay attention, even with 5-sigma dicrepancies. They are control plots, they show where mismodelling might be, and of course, often really correlated...

    And yes, maybe there is model where jet4 vs lepton is the discovery one...

    Poetry ...... ? How profound .....

    dorigo
    Allan, thanks for your stepping in the spotlights. Now please leave the scene. You have not taken the care to read through my posts on the CDF signal, and why I believe it is not new physics.

    Cheers,
    T.
    Don't worry Tommaso, since you clearly have no arguments for why you signed the CDF 3-sigma paper I will leave you in peace with your little blog ("spotlight")..

    The fact reminds, however, that you and your CDF colleagues have to hang your heads in shame for writing a nonsense paper that clearly has been promoted by the CDF and FERMILAB management as evidence for new physics.

    And to after that make statements about an ATLAS internal note that you have not read (but perhaps contains a fluctuation that is more significant than what you just published) is also ludicrous.

    Cheers,
    A.

    "They find a signal that seems consistent, in mass and resolution, with what one would expect from a Higgs decay, if the Higgs were sitting at 115 GeV ... I think the signal is false for a few reasons ..." Does M-theory predict the Higgs boson? Can M-theory use brane interactions to model any physics whatsoever? My guess is that M-theory is correct but M-theory needs the addition of new physical hypotheses. I claim that the Rañada-Milgrom effect, which is that the -1/2 in the standard form of Einstein's field equations needs to be replaced by -1/2 + sqrt((60±10)/4) * 10**-5, is approximately correct for 2 reasons: astronomical observations at low gravtiational accelerations and the Pioneer anomaly. Do I know what the Rañada-Milgrom effect means in terms of physics? No, because the effect might be real or apparent. I think that the Rañada-Milgrom effect needs somehow to be mathematically incorporated into M-theory. If M-theory gets new physical hypotheses, then M-theory might make a precise prediction concerning the Higgs boson.

    So much!!!
    I cannot accept this kind of information in scientific world.
    It is enough to send an anonymous "bufala" (if do not understand it, just learn it)
    to trigger a world wide stupid discussion on something that may be just nothing.

    1) If the "bufala" is a true abstract by Wu et al., sent to damage the author reputation
    (since that signal is a "bufala" on its turn)
    **** or
    2) If the "bufala" is a true abstract by Wu et al., sent by the authors to gain credit spreading in an foxy way their names
    (with the hope that the signal will not result to be a "bufala")
    ****or
    3)If the "bufala" is just a joke and Wu et al. have nothing to do with it

    THERE IS NO REASON to amplify the rumors or to favour or damage people on the basis
    of something which has not followed the scientific procedures.

    Scientific bloggers have to decide: either they act as scientists either they act as journalists ready to publish
    any piece of information simply because it is "HOT".

    Tommaso,

    You are wise beyond your years to predict that this is not the Higgs - clearly there are some inconsistencies in the data. There will probably be many more of these false starts in the search. I think there are far too many expectations right now and even the slightest hint of a new particle will make the news. Thanks to you for sticking to your guns of skepticism!

    Scientists (HEP ones in particular) must be amongst the most vicious creatures on earth. I think I would feel safer being alone in a room with an angry gorilla than a physicists who believes he has just discovered a new particle.

    That's a pretty strong statement. What in this story possibly makes you feel that way?

    Sorry, I'm just venting my feelings out loudly by trying to be sarcastic.
    Anyway, its almost as if science is not just a job after all. In a way, I perceive scientists are being missionaries, giving their "life" to spread the word of science (which makes, at least some of them, some sort of fanatic).

    The details you provide are really exciting...
    Your bet offer, however, just increases my gut feeling that you speculate that ATLAS has something real...I'll explain:
    It is more likely than note that you will win the 1000...but even if you lose you win!...for a 1000$ you'll be linked to the Higgs exotic discovery and the scientific trivia... Furthermore, taking the media 'deep' interest in Science, you'll be more famous than anyone in ATLAS... So do increase your bet offer?