Today I’m attending the start of a several day workshop at the CERN laboratory (host of the Large Hadron Collider [LHC]). This is bringing LHC experimentalists and theoretical particle physicists together to hear about and discuss not only results from the (successful) search for the Higgs particle but also from many other searches (so far unsuccessful, but still important and instructive for our understanding of nature) for other new particles and/or forces, as well as relatively high-precision tests of the Standard Model itself. This should help those of us who were distracted for the past week by the discovery of the Higgs-like particle to catch up with everything else that the experiments reported at the ICHEP conference. Will update today or over the next few days if anything striking is presented.
Blog – Page 52 – Of Particular Significance
I’ve finished my third and fourth articles on the Higgs discovery (the first two being on the data itself and why it is convincing, and on the great skill and the bits of luck that led to a discovery occurring so soon.) The new articles are about why I personally think the new particle is almost certainly a Higgs particle of some type, and about the outstanding question of whether this particle is the simplest possible type of Higgs (the Standard Model Higgs particle) or not.
I believe that nothing I’ve written in these two new articles is original; it has all (or almost all) been stated in papers or preprints by other people. That said, what’s in these articles represents my own personal views (since at this early date I have no way to know what fraction of my colleagues agree with me), and those views are not yet set in stone… so experts with well-reasoned arguments are encouraged to try to change my mind.
POSTED BY Matt Strassler
ON July 12, 2012
A distant topic, yet not distant at all. Science, as a process, creates trustworthy knowledge; it has proven this over and over, and much of our economy is based upon it. But scientists? As individuals, they are just as human as anyone else: they make mistakes, harbor biases, believe things without much evidence, overstate their cases, and do all sorts of problematic things. Some are a lot more reliable than others, and often the unreliable ones are the ones who take their scientific case to the media (the reliable ones often not seeing the need to do so). Consequently, media stories on science are on average somewhat less reliable than the ones scientists produce and read.
So when a brand new science story makes the headlines — say, the possibility of faster-than-light neutrinos from the OPERA experiment at the Grand Sasso laboratory (withdrawn before publication due to discovery of a technical problem), or the bacteria substituting arsenic for phosphorus as claimed by a group of scientists who first predicted the possibility and then claimed to find it (here’s the abstract of the published paper in Science magazine, and a popular New York Times article about it) — caution is advised. [Cold fusion, anyone? Utah’s governing institutions should perhaps have been a bit more patient…]
Multiple arguments against the arsenic-incorporating bacterium result have been made from the beginning. Now two new papers (#1, #2) have hit Science magazine, and the press. Both argue (among other things) that the bacterium in question is still dependent on phosphorous and that there is no sign of arsenic in its DNA.
Which is all to say that reproducibility lies at the core of scientific research. It is the process of confirmation and cross-checking of a result that allows a media story that begins “Scientists say…” to be transformed into a textbook that begins “Science says…” When you read a story in the press, you should always look for the key indications that multiple and separate groups of scientists agree on the result — not necessarily that there is broad consensus, but at least that the scientists making the claim aren’t entirely out on their own. [For the recent discovery of the Higgs particle, we have two different experiments making the claim.] If those indications are missing, I’d advise you to file the result under “unconfirmed,” and not to bet on it.
POSTED BY Matt Strassler
ON July 10, 2012
Super-busy at the CERN laboratory outside Geneva; lots of new data becoming public as it appears at the ICHEP conference, lots of theory papers flying around (not all of them accurate and uncontroversial) trying to interpret the Higgs measurements, and lots of work to do preparing the experiments for their further measurements of the Higgs and for their searches for other particles and forces. Updates to this website are getting slotted in when possible. In addition to my recent summary post from Thursday, I put up an article Friday about the data itself and why it is convincing [updated today with some new plots], and a new article today about how a lot of skill and a little luck led to the beautiful results we saw on Wednesday. Enjoy! [If you have friends asking you why the Higgs particle matters, you can have them read my article about it.]
POSTED BY Matt Strassler
ON July 9, 2012
[July 6 UPDATE: very busy with work here, but I have finished a short article briefly describing the data, and why it is convincing that a new particle has been found.]
July 5: A wild day at the CERN laboratory yesterday, continuing into today and surely the rest of the week. [If you’re a lay-person wondering what all the fuss is about, you might want to read my article “Why The Higgs Particle Matters“, or watch my year-old video clips that explain how one searches for the Higgs particle, or read the Higgs FAQ.] [Very well-written and almost entirely accurate articles at both the New York Times and the BBC.]
The contrast from last December is profound. After last December’s presentation on the search for the Higgs particle at the Large Hadron Collider [LHC], whose results I called “inconclusive” and other bloggers called “firm”, most ATLAS and CMS experimentalists I talked to were expressing, in public and in private, something between extreme caution and cautious optimism. I can’t count the number of times that senior experimentalists told me a story about a 3 sigma result that they’d seen disappear because of a subtle mistake. Though many theorists were convinced, many other theorists (despite what you hear from some other bloggers) shook their heads and expressed deep caution. Discussion at the CERN cafeteria and in the hallways focused on which parts of the data were most trustworthy and whether the discrepancies between what ATLAS and CMS had observed made the result unstable to small changes. All in all, despite what all the other bloggers said, I personally did not talk to a single experimentalist who felt the result was secure — which is not to say (this is an important distinction, please read carefully and please do not misquote) that anyone (including me) thought the hints were clearly a mirage. The problem, as I explained at the time, was that you could run an argument that made you confident in the hints, and you could also run an argument that made you lack confidence. Well, evidence isn’t firm until the argument in favor is a lot stronger than the argument against, and that wasn’t true in December. The evidence did improve somewhat by March, though the improvements were kind of up and down.
By enormous contrast, after yesterday’s presentation I did not speak to a single person who expressed serious doubts that ATLAS and CMS had made a discovery. (The most negative comment was from an experimentalist who wished ATLAS and CMS hadn’t been forced, by the early-July scheduling of the ICHEP conference, to do their data analysis so soon; he would have preferred to have twice as much data and a result that left him with absolute confidence. Well, if that’s the worst thing anyone can say…) What’s changed from December is that every argument you can make comes out in favor of the result being real; I’ve been unable to think of any argument against it, nor have I spoken to anyone who has proposed one. All the conversation now is on what the discovery means and on what to do in coming months.
How did a result that was inconclusive in December become so convincing in July, with just a doubling of the amount of data? The answer, as far as I can tell, is that a number of things that could have gone wrong all went right. I’ll go through this in more detail later, but suffice it to say for now that the experts who operate the accelerator and the two detectors all proved, yet again, that they are extremely smart and capable, and on top of that, they had some good luck that brought them to results almost as strong as anyone could hope for. Only time will tell whether the two experiments both got a bit lucky with a statistical fluke or whether the Higgs is actually a bit easier to find than theorists expected — but on top of this, the LHC produced somewhat more collisions than estimated in advance, the experimenters dealt admirably with the extreme collision rates, many new techniques for improving the measurements were developed, and these numerous small bits of good news combined for a nearly best-case scenario. Yesterday’s results were close to the optimal that could have been possible, given the amount of data; to have both experiments see clear signs of a new particle with a mass of about 125 GeV/c2 in both of their “easy” searches (for Higgs particles decaying to two photons, and for Higgs particles decaying to two lepton/anti-lepton pairs) was a lot to ask for, but it’s what we got!
My goal for today and tomorrow, if I can squeeze it in — obviously my highest priority right now is conversations with my professional colleagues about interpreting the result and discussing what needs to be on the agenda for the rest of 2012 and 2013 — is to explain to you:
- What does the current data actually show?
- What in the data makes the evidence in favor of a new particle so convincing?
- What elements of first-rate experimental technique and plain-old luck combined to make the result so strong?
- Why I am personally so convinced (more than the experimentalists seem to be right now) that the new particle is a Higgs particle, as opposed to something else?
- To what extent is this particle consistent with the simplest Higgs (a “Standard Model Higgs”) as opposed to a more complicated type?
Maybe getting through this list will take me into next week. At some point I’ll write more about the implications of this being a simplest Higgs or not, but probably not before the middle of next week. And hey, it’s also time to revise the Higgs FAQ!!!!
So stay tuned to this channel! I’ll alert you when I finish writing the answer to each of these questions.
POSTED BY Matt Strassler
ON July 5, 2012
[This paragraph was my introductory paragraph from this morning, before the presentation. Details of the presentation follow.] IndependHiggs Day has dawned, warm and hazy. Yesterday, at the CERN laboratory that hosts the Large Hadron Collider [LHC], all the discussion at lunch, and over afternoon coffee and evening beer, centered on the Higgs particle (here’s my Higgs FAQ, my video clips for non-experts about how the Higgs search is done, and a recent article for non-experts explaining its larger importance;more detailed background on the Higgs is linked from here), and on today’s presentation to update the search for it. The mood is ebullient and excited; everyone is anticipating a very big step forward, perhaps a definitive one. Gone is the uncertain mood of December, when CERN preceded its presentations with a warning that the results shown then would not be conclusive — a warning that is notably absent this time. It’s a party atmosphere, and a media circus; many luminaries are here, invited by the director to witness the event. The press will fill an entire auditorium all their own; physicists will be spread out over perhaps a dozen auditoriums. It’s been suggested that CERN should have rented a soccer stadium in Geneva; the small size of the main auditorium at the lab reflects how much smaller particle physics experiments were just 30 years ago.
What I will be watching for in the presentations today is the following (to be updated when I know the answers): Here’s what happened in the presentation today:
[8:50 Professor Higgs has entered the room.]
[9:00 CERN Director General Rolf Heuer very brief opening remarks]
First, CMS (presented by spokesperson Joseph Incandela, from the University of California Santa Barbara): (5.2 inverse fb of data, with 5.6 for muon analyses, improvements on many fronts)
- Is there a new particle apparent, as a bump in a plot, in the search for a Higgs of mass near 125 GeV/c2 decaying to two photons? Yes!! 4.1 sigma, a bit above standard model expectation though not too much
- Is there supporting evidence of a bump, at around the same mass as for the photon search, in the search for a Higgs decaying to two lepton/anti-lepton pairs? Yes! 5 or 6 events above background, 3 sigma, a bit below expectation but quite consistent with standard model
- TOTAL 5 SIGMA!!! LOUD APPLAUSE…
- Is there supporting evidence for an excess of some sort in the searches for a Higgs decaying (a) to a tau lepton/anti-lepton pair, (b) to a bottom quark/anti-quark pair, and (c) to a lepton, anti-lepton, neutrino and anti-neutrino? (a) not at all, but very low statistics (b) not incompatible, but still low statistics (c) preliminary technique, yes
- TOTAL 4.9 sigma, EXPECTED 5.9 sigma ;
- MASS 125.3 +- 0.6, preliminary
- Is the 8 TeV collision-energy data from 2012 roughly consistent with what was seen in the 7 TeV data from 2011? Yes
- Does the evidence in favor of a new particle support the idea that this is a Higgs particle? Absolutely!!!! As I have explained elsewhere, an observation of a signal in both photons and leptons, with even roughly the ratio predicted by the Standard Model, is a very strong argument in favor of the new particle being a Higgs particle.
- Does evidence in favor of this particle suggest that it is a Higgs, but not a Higgs of the simplest type (i.e., that it is not a Standard Model Higgs)? No signs of (statistically significant) non-Standard Model behavior
Next, ATLAS (presented by spokesperson Fabiola Gianotti, from CERN): (up to 5.9 inverse fb, and various improvements, some quite important)
- Is there a new particle apparent, as a bump in a plot, in the search for a Higgs of mass near 125 GeV/c2 decaying to two photons? Yes!! 4.5 sigma , 3.6 sigma with look-elsewhere effect over 110-150 GeV: (cross-section almost twice as big as expected! but only 2 sigma excess); mass about 126.5 GeV
- Is there supporting evidence of a bump, at around the same mass as for the photon search, in the search for a Higgs decaying to two lepton/anti-lepton pairs? Yes!! 6 or 7 events above background, 3.4 sigma (2.5 sigma after look-elsewhere over 110-140), cross-section again a bit large, 1.3 +- 0.6 of Standard Model expectation
- Is there supporting evidence for an excess of some sort in the searches for a Higgs decaying (a) to a tau lepton/anti-lepton pair, (b) to a bottom quark/anti-quark pair, and (c) to a lepton, anti-lepton, neutrino and anti-neutrino? Nothing from 8 TeV collisions shown today
- TOTAL 5.0 SIGMA!!!!!! LOUD APPLAUSE…
- MASS 126.5 GeV (from photons only; leptons are lower; no error bar given, so measurement of mass is not complete) with 1.2 of standard model production rate
- Is the 8 TeV collision-energy data from 2012 roughly consistent with what was seen in the 7 TeV data from 2011? Yes
- Does the evidence in favor of a new particle support the idea that this is a Higgs particle? Absolutely!!
- Does evidence in favor of this particle suggest that it is a Higgs, but not a Higgs of the simplest type (i.e., that it is not a Standard Model Higgs)? No significant deviations from Standard Model though two-photon rate is currently 2 sigma high. Two sigma is not enough to be excited about. This is especially since the Standard Model prediction for the overall cross-section is a very tricky calculation; its current precision is estimated at 15%, but perhaps one might worry about that estimate.
Then:
- Is what CMS observes largely consistent with what ATLAS observes? Absolutely!!
- Are there any notable discrepancies between the two experiments that might undermine confidence in their results? None! The discrepancy of about 1.2 GeV in the masses quoted is not official, since ATLAS does not yet have a final mass measurement with a proper uncertainty estimate. Even if I take the ATLAS estimate as if it were a mass measurement, if I put a similar uncertainty on it as CMS has quoted, the discrepancy between the two experiments is below 2 sigma, not enough to cause concern at this time, especially given the strength of the signal in each experiment separately.
WOW!!!! CONGRATULATIONS LHC, ATLAS and CMS !!!
[Heuer celebrates a global success… A standing ovation for all…]
[No one has any questions; the data is so clean and so convincing!]
[Some nice words from the inventors of the idea…]
POSTED BY Matt Strassler
ON July 4, 2012
Excitement is reaching fever pitch as the presentation at CERN on the Higgs search approaches! What’s important is that they measure By now the experiments have actually finished their analyses, and the press is reporting (harmless) rumors that both of the big Large Hadron Collider experiments, ATLAS and CMS, are seeing something. Presumably, assuming the rumors aren’t wrong, what they are observing, using this year’s data, is signs of a Higgs-like particle with a mass of 125 GeV/c2 that are roughly similar to what they reported in December, January and March using last year’s data. The details will be fascinating to see!
UPDATE: The CDF and DZero experiments at the now-closed Tevatron just updated their Higgs searches, and they find some amount of evidence in favor of a Higgs particle being produced through its interaction with W and Z particles and decaying to bottom quark/anti-quark pairs. Resonaances has a summary. This process is interesting because neither this production mechanism nor this decay mode are yet accessible to ATLAS and CMS; they don’t have enough data collected yet. One should be a bit cautious about such difficult analyses, but taken at face value these measurements are complementary to what ATLAS and CMS can tell us on Wednesday.
What’s all this fuss about? For the non-technical reader (and/or for your non-technical friends) I’ve written an article trying to put this historic moment in perspective, using language that is as non-technical and unfrightening as I can manage. If you agree that this is a good article for non-experts, please forward the link to others!
For the reader who wants to follow more details: Let me remind you of the sharpest questions that we’ll be asking on Wednesday, many of which are the same or almost the same as those we asked last December. (You can review my various background articles on the Higgs if you want to understand why these are the right questions):
For both ATLAS and CMS, we will ask: (more…)
POSTED BY Matt Strassler
ON July 2, 2012
Today is the anniversary of this website, born June 29, 2011. And it’s just in time for what could be the biggest news in particle physics in many years. If we’re lucky, on July 4th the teams that run the ATLAS and CMS experiments at the Large Hadron Collider [LHC] will reveal strong evidence for a Higgs particle of some type [for more info and background click here]. Or, if we’re equally lucky, they’ll reveal strong evidence ruling out the simplest type of Higgs. Only if the results are ambiguous will we have to wait yet again for another six months of data.
Why does this website exist? For one thing, I thought perhaps I could help address the desire of many in the public to understand more about particle physics and about the process of doing science. Also, I was concerned that if the Higgs did not show up in 2012, there was a big risk of public and media misinterpretation of the scientific situation, which I hoped I could help counter. And with the recession taking down my long-standing LHC research plans, I was looking for some non-scientific way to be useful.
The year has been a mixed bag. The site’s been quoted several times in the media, and science journalists have told me they’ve found it useful. On the other hand, the site’s readership, which leapt to about 2000 hits a day early on, has stayed fixed at that level for more than eight months. Then there are the controversies. I don’t think one can run a useful modern website without a blog that reports the news in the field, and to properly address important issues with real integrity requires one to take unpopular stands on controversial issues. Unlike some of the other more populist bloggers out there, who seem to thrive on this kind of thing, I hate it. And finally, communicating particle physics is fun and rewarding, but also problematic. Much of my readership has also read Brian Greene, Lisa Randall, Lenny Susskind, and the like… and will (or should!) soon be reading Sean Carroll’s upcoming book on the LHC and the Higgs… and all of us well-meaning physicists are explaining the same things in slightly different ways. I’m worrying we’re creating, collectively, a lot of confusion.
For now, the website will continue as is, through the LHC Higgs presentations and into the follow-up period in early July. If strong evidence for the Higgs emerges, the immediate dangers that helped motivate the site’s existence will recede for a few years; there will be general agreement, as there should be, that the LHC has been a resounding success and has a bright scientific future ahead of it. In that case I’ll take a break from reporting all but the most important news (I recommend Resonaances and Cosmic Variance as news sources) and instead will focus on giving the website a needed reorganization; right now it’s very hard to navigate. As for whether the site has a future, and what form that future might take, that will take some thought.
So, a quiet Happy Birthday to this website Of Particular Significance. And then let’s look forward to the news that really matters — the news from Nature — and get the cases of champagne ready, in case the time has finally come to pop the corks.
POSTED BY Matt Strassler
ON June 29, 2012
Coming very soon: News on the search for the Higgs particle by CMS and ATLAS, the two big experiments at the Large Hadron Collider [LHC]. Presentations updating the search are expected on July 4th, IndependHiggs Day, at 9:00 am Geneva (Switzerland) time, at the CERN laboratory, which hosts the LHC. The talks, like those of December 13th, 2011, are expected to be technical and intended for experts, though non-experts with some significant amount of background might enjoy directly seeing the data and sharing in the sense of excitement.
The current phase of the search is aimed at either discovering or excluding the simplest type of Higgs particle, known as the Standard Model Higgs. If you are interested in understanding what this particle is and how one looks for it, you can read
- The Standard Model Higgs particle
- How it is produced
- How it decays
- How it can be sought and studied
- Why a lightweight Standard Model Higgs (e.g. with mass near 125 GeV/c2) is hard to find
To learn more about what the Higgs field and particle are and do, try
- The Higgs FAQ 1.0
- The Known Elementary Particles and Forces
- The Known Particles — If the Higgs Field Were Zero
Regarding Higgs particles that are more complex than the Standard Model Higgs, and that may be harder to find, you can read
- Implications of the Higgs Searches as of 9/2011 (out of date in many details, but still relevant and correct concerning more complicated Higgses; to be updated soon)
- Why a Lightweight Higgs Particle is a Sensitive Creature
POSTED BY Matt Strassler
ON June 27, 2012
Ever have the experience of feeling that no one is listening to you, and so, to make yourself heard, you yell really loudly? And then discover that one of the key people you were trying to reach is standing right behind you?
That’s a bit how I feel after my recent post about Tuesday’s article in the New York Times on the search for the Higgs particle at the Large Hadron Collider [LHC]. My readership is minuscule compared to Dennis Overbye’s, so I shouted. But Mr. Overbye, to my surprise, read the post. Clearly I could have made my points more gently, and for the unnecessary stridency of my tone, Mr. Overbye, I apologize.
I also believed the NY Times article contained an error, and said so. Mr. Overbye defended himself in a comment to my post, saying that the phrasing he chose was meant to imply the correct situation without going into too much detail. I accept this was his intent; I do understand that squeezing these complex ideas into very short articles is a huge challenge, one that he and his colleagues often do very effectively.
Still, in this case, the phrasing chosen could easily lead to an unfortunate and problematic misunderstanding in the wider public — negating the otherwise admirable features of the article. And the risk of causing this particular misunderstanding is the hot button issue on this website. I’ll explain why in a moment.
Before I go into detail, let me balance my negative comments, in the interest of fairness. As a commenter noted, Mr. Overbye carefully avoids referring to the Higgs particle (or “Higgs boson”, as most physicists call it [what’s a boson? just a particular type of particle — click here to read more]) as the “God particle”, a term invented purely to sell a book, and detested by most physicists I know. Thank you, Mr. Overbye, for setting a high standard here. And Mr. Overbye successfully evokes the current mood of extremely high excitement in the field — that 2012 is a very, very big year, in which huge questions bothering particle physicists for decades are finally coming to a head.
But what precisely are those questions? And why do I think it matters?
I do think it’s useful to look at why Mr. Overbye’s phrasing could be disturbing to some particle physicists. First off is the notion that the upcoming conference called ICHEP is “the boson’s last stand”.
In disagreeing with this statement, I am not (as some commenters thought) making a statement of theoretical prejudice. This has nothing to do with what I believe about nature, or what anyone else believes. I am making a simple logical point.
What is the “Standard Model”? It is the set of equations used by particle physicists to describe all known particles and forces at the LHC, along with the simplest possible Higgs particle. [Sometimes this is called the Minimal Standard Model.]
What the LHC experimenters are doing right now is an exhaustive search for this `simplest Higgs’. This search is nearing completion. (Caution: completion may not come at ICHEP. The limited data available so far means that ambiguities may still remain, due to statistical flukes. In that case we’ll have no choice but to wait for the end of 2012.) When the search is done, either a Higgs particle will have been found (perhaps a simple one, or perhaps a more complex one uncovered more or less by accident) or the simplest Higgs will have been ruled out.
Suppose indeed the simplest Higgs is definitively excluded by the data. Which of the following conclusions follows logically?
- The simplest Higgs particle does not exist in nature.
- The (Minimal) Standard Model is not a complete description of nature.
- There is no Higgs particle in nature.
The first two conclusions are logically correct, as well as scientifically spectacular. The third would be even more spectacular, but does not follow. But in saying that ICHEP is “the boson’s last stand”, Overbye gives the strong impression that the third conclusion will follow.
What is actually having its last stand, now or soon, is the Standard Model, [or Minimal Standard Model if you prefer that name] and its simplest Higgs. Professor Higgs and the others — Brout, Englert, Guralnik, Hagen and Kibble — will be disappointed if the Higgs doesn’t show up in its simplest form, but will have no reason to give up hope.
Why is this such an important distinction? Because a non-expert reading the phrase “the boson’s last stand” might naturally conclude that if no Higgs particle discovery is announced at ICHEP, it’s all over… that we know there is no Higgs particle in nature, and the search for the Higgs is done. And the natural next question for many people will be: “ok, but then what do we need the LHC for?” And for others, “so you mean to tell me that theorists said for 50 years there’d be a Higgs particle, and we paid for this 9 billion dollar machine, and the Higgs isn’t there?!” Personally, I do not want to see the New York Times creating these sorts of very dangerous misunderstandings, at a time of severe economic crisis. (Anyone who thinks no dangers lurk here should consider the last two decades of history carefully.) And that’s why I reacted so strongly to Mr. Overbye’s article.
According to Mr. Overbye, he was trying to convey this distinction. I realize these things are very hard to do, but, with respect, I think in this case it wasn’t done clearly. And that’s partly because he added the statement that “theorists will have to go back to the drawing boards” — which implies that theorists will all be so astonished and befuddled if the Higgs doesn’t turn up at ICHEP that they’ll all have to go back to square one.
Will the demise of the (Minimal) Standard Model and its simplest Higgs send theorists back to the drawing board? No. Theorists have not been idle over the past decades. They’ve been at the drawing board the whole time; it’s their job not to be satisfied with the conventional wisdom. It’s not the drawing board but the library and the desk drawer and the computer archive to which they will turn. And in those places you will find dozens and dozens of sensible alternatives to the simplest Higgs, many of which are harder to find than the simplest one and will still be worth searching for, well beyond 2012. And you will find numerous papers, by famous and less famous scientists, showing how nature can have a Higgs field but no Higgs particle; this situation (usually omitted by science journalists, because it is admittedly very hard to explain in a few words) always comes with other scientific opportunities for the LHC. [I’ve written about this here, if you want to learn more; see section 6 — the article is out of date in its details but not in its scientific points.] [Experts: by “Higgs field” I specifically mean any effective field whose would-be Nambu-Goldstone bosons provide the longitudinal components of the W and Z particles. You may prefer a different terminology, but I hope you do not disagree with the science. The example I have in mind is technicolor, and its various cousins.]
If late this decade there’s still no Higgs particle and still nothing else unexpected in the LHC data, then you’ll find most of us at the drawing board.
I should note that a few commenters stated their opinion that if the simplest Higgs, or something like it, doesn’t show up in the current search, then they will be sure there is no Higgs particle in nature, because “nobody believes” these alternatives to the simplest Higgs. First, their opinion is one of theoretical prejudice, not logic; and if scientists’ beliefs were always right, experiments would be a lot less important than they are. And second, the point is not that anyone believes a particular alternative; I don’t “believe” in any specific one myself. The point is that there are so many, and so easy to create. It would be foolhardy to dismiss the possibility that nature might hide the Higgs from our initial searches.
Also, there is an unfortunate public perception (partly due to physicists cutting corners in public statements) that theoretical physicists said that “there is a Higgs particle in nature” and that the experimental physicists built the LHC to find it. This is too glib. As I have written in more detail elsewhere, what theorists said (collectively) is that “there is a Higgs field in nature” — a Higgs particle being likely but not a certainty. The LHC was built to help us understand the Higgs field, and was designed to handle both the cases where a Higgs particle would be found early on, and the cases where it would not be found early, or at all. In short: particle physicists have come to this point fully prepared.
And we need the news media to convey this. Having provided several billion dollars for this machine, taxpayers and politicians around the world rightly expect particle physicists to do a first-rate job with the money. We have a reputation to uphold. If the media, directly or indirectly, leads the public to view us unfairly as bewildered, stunned, unprepared, or otherwise incompetent, this would be very damaging. And so I feel that cannot sit idly by if a New York Times article, even unintentionally, could imply to many readers that not finding the Higgs by ICHEP would mean that nobody in the field would have any idea what to do next.
I myself write to explain science, mainly particle physics, to the public, and I know that science journalists everywhere have a very tough job. Mr. Overbye, in his position at the NY Times, can have huge influence on scientific understanding and science policy in the public, and consequently he has responsibilities that make his job even tougher. His contribution to public excitement about the current moment in particle physics is more than welcome. But isn’t there some way, in a few words, also to convey the decades of careful preparation by the particle physics community, not just for the conventional wisdom but also for the broad range of alternatives? And not just for this critical moment, but for the decade of LHC studies that lies ahead?
For even if we see strong evidence of a Higgs-like particle at ICHEP, the correct understanding of that particle — in particular, determining whether it is or isn’t a `simplest Higgs’ — may take many years. And we’re prepared for that.
POSTED BY Matt Strassler
ON June 25, 2012
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