As far as I’ve been able to tell, there’s still nothing definitive one way or the other about the SM Higgs, as the experiments continue to analyze data from the now-finished 2011 pp run. Starting Monday is the HCP 2011 conference which at one point seemed to be a possible venue for announcement of confirmation of hints from early this summer of a Higgs around 140 GeV or so. Those hints disappeared later in the summer, so conventional wisdom recently has been that not much new will come out next week in Paris. A new blog entry from one of the organizers refers to this disappointment, leading to worries about conference attendance, but adds some dramatic and mysterious news at the end. It seems that some experimental collaboration requested a last-minute slot at the conference to unveil a new result that might be the highlight of the conference. They’re on for 15 minutes on Monday, still not announced which collaboration this is, who the speaker is, or what their title is. This may very well have nothing to do with the Higgs: maybe something else travels faster than the speed of light…
At HCP2011, ATLAS will have new results from the H->ZZ->llnunu channel (already released, see here) and from the H->ZZ->llqq channel. Unfortunately neither of these are relevant to the low mass region where the Higgs is believed to be hiding. I don’t know what CMS has up its sleeve. One other thing that will be released is the combination of ATLAS and CMS summer conference data, which will exclude the Higgs at 95% confidence level from 141-476 GeV (and come very close to this exclusion down to about 135 GeV).
It looks like release of new data in the channels that are sensitive to a low mass Higgs will wait longer, until the experiments have had a chance to do some analysis on the entire 2011 data set. Mid-December has been rumored as a date, and a logical bet would be that the CERN Council week would be the time for this, in particular at the Scientific Policy Committee meeting on December 12-13. Rumors going around about this are that there’s still nothing definitive in the crucial H->gammagamma channel, and that in the H->ZZ->llll “golden channel” (very low background), one experiment is seeing no excess at low mass, the other is seeing an excess. Higher quality, better informed rumors are encouraged…
Nature reports here on the discussion at CERN about what to do in the (wonderfully exciting…) event that the SM Higgs is not seen. The first action they’re taking is semantic: if no Higgs is seen at the 95% confidence level, instead of saying that this “excludes” the Higgs, they will announce that it “disfavours” it. So, the first reaction will not be jumping for joy, but a defensive one about how it might still be there.
Whatever comes out in December, I hear the plan is to wait for the Moriond conference at the beginning of March to release a result combining data from all channels (separately for each experiment). The Tevatron may have a result to release then too. Philip Gibbs will then swing into action for the full combination.
Update: Via Philip Gibbs, this talk includes the information that “The CERN DG has requested updates for December council”. Not clear to me if the plan is to release these publicly, or to try and keep them confidential (which may not be easy…).
Update: The mystery new result is from LHCb, a 3.5 sigma observation of CP violation in an unexpected place. Details here, Jester has analysis here.
“A new blog entry from one of the organizers refers to this disappointment, leading to worries about conference attendance, but adds some dramatic and mysterious news at the end.”
There is your answer in a nutshell: “… worries about conference attendance, …” And so it is a self-fulfilling prophesy that conference organizers **must** promise the prospective audience some sensational news. “… but adds some dramatic and mysterious news at the end.” Et voila!
Don’t blame string theory for any of this. And don’t restrict the responsibility for this state of affairs to HEP.
“Higher quality, better informed rumors are encouraged…”
In other words you are looking for something like a 5-sigma rumor to distinguish the event from the noise floor? Or if we collect a sufficient number of 3-sigma rumors is that adequate…
I think rumors and hype are not so distant cousins… There is a problem with honesty in hyping results or spreading false rumors. If someone if spreading “true rumors”, you need to realize that that person has agreed not to discuss unapproved results but is doing it anyway after saying that they would not do that. This is not about whether collaborations should or should not impose a ban on discussions of internal results. Simply put: if you agree to something, abide by it. Don’t encourage hype and don’t encourage the spreading of rumors. Science does not profit from either.
Apologies for OT comment, but I just received an email about this new particle physics textbook from Princeton, purporting to be “a cutting-edge introduction to the field, preparing first-year graduate students and advanced undergraduates to understand and work in LHC physics at the dawn of what promises to be an era of experimental and theoretical breakthroughs.” Do you have any thoughts on the timing? I suppose it is timely in one sense, but I wonder how they decided how much speculation/prognosticating to put in or leave out…
That’s a serious book, from the experimental view-point, with only a minimal level of theoretical speculation. The LHC will be operating for many years, and most of what’s in the book will continue to be relevant. The author has chosen to go ahead and publish even though some of the material may be out of date soon. Nothing wrong with that, if a field is moving fast, doesn’t mean people shouldn’t try and write textbooks about it.
I won’t get into the debate about discussing rumors about unapproved results, other than to note that I try to do so accurately, and only when I have some good reason to believe the rumor (note that information leaks out in many ways…). I don’t think this damages the progress of science.
Also note that much of the information in this posting that may be confidential is not unapproved analysis of data. As far as I know, this summer’s ATLAS/CMS combination is approved and final. Sometimes people have results that have gone through the proper vetting procedure, and they’re just keeping them confidential for non-scientific reasons, e.g. waiting for some conference or press release. Other information in this posting is rumor/speculation about tentative scheduling of future releases of data, and I actually don’t see any good reason for that to be confidential.
…or maybe something else violates CP at 3.5 sigma level.
It seems that some experimental collaboration requested a last-minute slot at the conference to unveil a new result that might be the highlight of the conference. They’re on for 15 minutes on Monday, still not announced which collaboration this is, who the speaker is, or what their title is.
W mass from CDF?
According to my sources, it’s going to be the LHCb measurement of a large CP asymmetry difference between D -> K K and D -> pi pi decays.
Jester, your sources are right. Can we start discussing what is the Standard Model expectation for that?
Do the CERN physicists have a Higgs betting pool?
“The first action they’re taking is semantic: if no Higgs is seen at the 95% confidence level, instead of saying that this “excludes” the Higgs, they will announce that it “disfavours” it.”
How far will they have to go to “exclude” it? Is it just that they want perpetual funding to go on searching and have job security forever? Not only does the Higgs not predict a certain energy, but the LHC experiments can’t definitely exclude it?? If these people were searching for ESP phenomena, would they be similarly cautious?
I think they want to reserve the word “exclusion” for a higher standard than 95% sure it’s not there, e.g. 5 sigma. In terms of communicating with the public, this is not unreasonable, since in this business analysis of systematic errors is tricky and “95% sure” has been known to be wrong more often than expected. However, “disfavored” sounds to me misleadingly weak…
In any case, I’m sure they’ll keep reporting 95% results, whatever they call them, and if the SM Higgs is excluded at that level, most physicists will start assuming it’s quite likely that it’s not there.
Indeed non-leptonic D decay seems to be it. Difficult to think of a tougher nut to crack, re. a decently clean SM prediction.
What about the Dec 16 CERN announcement buzz, though?
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I am not a physicist, just an interested observer. What impresses me is that if the SM Higgs is not found, there appears no particular direction to go. Yes, the kluge-assisted standard model is wrong, but so what? Technicolor seems doomed. String theory can retreat to any level of energy to avoid being refuted. What to do?
A situation where there’s no good theoretical idea, and experimentalists are hard at work producing results that might provide important hints sounds to me like a pretty good situation for a theorist. Far preferable to the LHC data just confirming the SM or some other well-known theoretical model. If the SM Higgs doesn’t show up, for the first time you’ll have an experimental result in radical disagreement with the SM, and that’s what we need in order to start figuring out how to do better than the SM.
What is the “Dec. 16 CERN announcement buzz”? Does this have to do with a plan to publicly update the Higgs search results at the CERN Council week?
Direct link to the HCP talk about CPV in the charm sector at LHCb.
Peter, or anyone else:
Do you know what happened about the muon (g-2) anomaly. what’s the latest
theoretical and experimental consensus?
I remember when it was exciting to think that a final theory was within reach. Now it’s exciting to think that perhaps everything we know is wrong and we need to start over again. Sheesh!
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