24 Comments on “Bump Hunting (Part 3??)”   rss feed

1. Sean on Mar 9th, 2007 at 12:18 pm

   Just imagine if you had called it “bulge hunting”…

2. adam on Mar 9th, 2007 at 3:35 pm

   Or ‘Girls Gone Wild: Particle Accelerator Spring Break’.

3. Sean on Mar 9th, 2007 at 5:50 pm

   More seriously, the media coverage has been very interesting. I think it’s partly a reflection of the unnatural way in which scientific results are often covered (and a way that blogs can ultimately prove very illuminating). To many busy journalists, science can look like a series of press releases announcing results of various levels of importance. They just don’t have the time or luxury to dig into the everyday workings of physics. Those of us on the inside know that two-sigma results come and go all the time. It’s good to get excited, because if it firms up into a higher-significance result then it’s immensely important; but the “natural caution” mentioned in the Economist article is just common sense.

   So journalists (and overly enthusastic Wikipedia editors, etc) see a blog post about your all-too-common bump in the data, and have a hard time distinguishing between that and the announcement of a discovery. But real science isn’t a series of quiet periods punctuated by momentous discoveries; it’s an ongoing discussion, an accumulation of small but important findings, an ebb and flow of excitement, and occasional dramatic breakthroughs. The real way that blogs might be changing things is not that new results will be posted here first (since they won’t), but that people might be able to get a more honest glimpse of how science really gets done.

4. tommaso dorigo on Mar 9th, 2007 at 8:52 pm

   Hi John,

   I wholly agree with your views - and Sean’s - on the matter. And I think there was ultimately no harm done to the field, or to our experiment, in the new scientist’s rather excited and somewhat inaccurate article.

   I have the feeling that blogs are destined to get in the way of how science is discussed, taking more and more space from the canonical venues. They are just too powerful ways to communicate. I think this is a good thing, since it is the way by which the gap between scientific papers and sports magazines will finally get filled.

   I retain an optimistic view of the future in this respect.

   Cheers,
   T.

5. Brian on Mar 9th, 2007 at 9:41 pm

   John,
   I loved your “bump hunting” posts - they conveyed a flavor of day-to-day science in which ideas and possibilities come and go. I am seldom treated to such up to the minute reports of work in progress. But you probably mentioned the bump to the person in the office next to yours - “only two sigmas, probably nothing, but exciting none the less, we’re going to analyze more data.” Well, [b]thank you very much[/b] for telling [b]me[/b] this time! Instead of the usual polished after-the-fact still life, you let me in on an earlier stage of the action.
   I also want to thank Julianne for her article [i]Well, That was Fun[/i],” from about the same time. As with any form of candor, you both openned yourselves to potential criticism. Whatever slings and arrows come your way as a result, you have my thanks.
   Brian

6. Arun on Mar 10th, 2007 at 12:28 am

   I think having scientists sharing the story of the chase as it happens will greatly help demystify science for a lot of people. So keep it up!

7. Charles Tye on Mar 10th, 2007 at 6:18 am

   Dear John,

   Your posts and Tommaso’s really conveyed to me the mixed feelings of excitement and uncertainty that you must be facing with this data. Even if nothing comes of it (and the chances are that it won’t) it has been an fascinating insight into the daily work of a particle physics. It has been a privilege to watch it happen from the sidelines.

   It’s precisely the fact that you don’t have to read about this kind of thing in the press after some journalist has put a spin on it and maybe altered/misunderstood some of the facts that makes blogs so interesting and important.

   Anybody who has actually read and followed your posts and Tommaso’s cannot be left with any other impression of particle physicists than careful and conservative scientists who go to great lengths to avoid deceiving themselves and others.

   Please do not be initimidated by the press trying to stir up controversy - they are just doing their job.

8. Arun on Mar 10th, 2007 at 2:00 pm

   Tomorrow’s The New York Times Sunday Magazine (not yet available on the web) has an article by Richard Panek on dark energy/matter.

   Quote:

   “Time to get serious” The PowerPoint slide, teal letters popping off a black background, stared back at a hotel ballroom full of cosmologists. They gathered in Chicago last winter for a “New Views of the Universe” conference, and Sean Carroll, then at the University of Chicago, had taken it upon himself to give his theorist colleages their marching orders>

   “There was a heyday for talking out all sorts of crazy ideas,” Carroll, now at Caltech, recently explained….”

   End quote.

9. Thomas Dent on Mar 10th, 2007 at 4:11 pm

   I read one of the articles - the Economist - it seemed to be saying that if the 2-sigma deviation does tell us something about reality, specifically a Higgs, then the Tevatron could make the discovery. Is this the case? I thought ‘discovery’ usually means 5 sigma, which needs a hell of a lot more data.

   How quickly could the Tevatron get to x sigma, where x is greater than or equal to 3?

   Oh, and why do journalists keep referring to ‘the God particle’? Surely it is the duty of every physicist to discourage this queasy mixture of religiosity and pop science, which no-one except science journalists uses anyway. (But who first thought of it??)

10. Arun on Mar 10th, 2007 at 6:48 pm

    Nobel Laureate physicist Leon Lederman coined the term “God particle”.

11. John on Mar 10th, 2007 at 8:17 pm

    Thomas, your question is an excellent one, and indeed we need to perform the calculation to predict, if our excess is real, how much data we would need to reach the golden five sigma level for discovery.

    For a quick and dirty estimate, though, typically you can scale up by the square root of the integrated luminosity (the size of our data sample). So, if we are at 2 sigma with the present sample, to get to 5 sigma we need something like 25/4 times more data, or about 6 times more. That won’t happen this year, but if we had three times more and D0 had three times more and we combined the samples we might be able to do it.

    Of course the other way to do it is to be clever and come up with new ideas to make the analysis more sensitive, and add other channels like Tommaso’s bb and the multiple-b-jet channel. We have a couple of things we are doing in the tau pair analysis, but it won’t double our sensitivity.

    As for the God particle thing, I really don’t like that term either… If I were religious I’d find it sacrilegious. And it hardly conveys the real meaning of the Higgs field and associated boson. Similarly I did not much like the “face of God” comments about the cosmic microwave background.

12. Jim Harrison on Mar 10th, 2007 at 9:18 pm

    Since priority is so valuable in scientific discoveries, isn’t it rational for researchers to report discovery before they’re sure they’ve discovered something? Or, to put things in a slightly different way, how can scrupulous researchers compete with good guessers? While individual researchers who jump the gun are likely to get swatted down, somebody who jumps the gun is likely to be the winner.

    As Alfred E. Neuman famously said, “Fools rush in and get the best seats.”

13. Chris W. on Mar 10th, 2007 at 11:32 pm

    Off-topic, but I thought I’d mention it:

    Out There (Richard Panek, NY Times, 3/11/2007)

    It hasn’t escaped the notice of astronomers that both dark matter and dark energy involve gravity. Early this year 50 physicists gathered for a “Rethinking Gravity” conference at the University of Arizona to discuss variations on general relativity. “So far, Einstein is coming through with flying colors,” says Sean Carroll, who was one of the gravity-defying participants. “He’s always smarter than you think he was.”
    . . . . . . . . . .

    “If the brilliant idea doesn’t come along,” Riess says, “then we will say dark energy has exactly these properties, it acts exactly like this. And then” — a shrug — “we will put it in a box.” And there it will remain, residing perhaps not far from the box labeled “Dark Matter,” and the two of them bookending the biggest box of them all, “Gravity,” to await a future Newton or Einstein to open — or not.

14. Thomas Dent on Mar 11th, 2007 at 6:59 am

    Since priority is so valuable in scientific discoveries, isn’t it rational for researchers to report discovery before they’re sure they’ve discovered something?

    Because accuracy and lack of bullshit are also valuable?

    Because it’s quite likely that most ‘discoveries’ announced on insufficient data are nothing of the sort … and will destroy your credibility?

15. Paul Valletta on Mar 11th, 2007 at 9:00 am

    Quote:”The team had found a signal which, in particle physics had a 2-sigma significance- a 1 in 50 chance of being a random fluctuation. Normally,to merit new particle status a signal must be significant to 5-sigma-where there’s only a 1 in 10 million chance of it being a fluctuation”.

    I would have thought these odds are incompatable?

    A small amount of data looked at, would theoretically have less chance of a fluctuation, than a vast pool of available data?

    More data should have more “bumps”, and all should adhere to the correct predicted signal.

    The more you look for something, the more chance you have to find it, it’s when you are ‘not’ looking for something and it exists at a specific location, (no matter how much available data one has!)..that this is the experimentalist dream?

    Surely, finding something twice, in a small amount of data, is far more exciting than finding soething once in a vast pool of data ?

16. Count Iblis on Mar 11th, 2007 at 9:30 am

    Does the number of x-sigma anomalies in High energy physics experiments follow the Normal distribution? Is there a publication bias (null results being under reported) causing a false impression that there are more anomalies than statistically expected, which in turn could be generating more speculative theory papers?

17. George on Mar 11th, 2007 at 11:39 am

    I’m just a layperson with an interest in the beauty of the thought processes are at the core of science’s attempt to understand the complex structure of the world we live in. I started reading CV because it puts me closer to the process of discovery by eliminating the filter of interpretation used in the popular press.

    I’m interested in the Higgs boson because I think it’s a beautiful idea even though I have no clue about the how or why it might work or even exist. So, I started following along the discussion here, the first post left me looking at the graph and asking myself, huh, what bump? As the topic developed over the following posts I think I came to at least crude understanding of what the graphs were displaying and what the fuss was all about.

    I’m assuming that the detector allows one to sift through the collision debris by detecting where it registers on the instrument as a function of its mass or energy. I’m also guessing that the decay process is producing signals from events that are either not part of what is being looked for, or that might otherwise be random, unexplainable or unknown. This causes noise in the results where the target particle, the ‘bump’, must be discerned against what is in effect a fuzzy mean. So if the amount of data analyzed is increased, the fuzzy background should tighten up within the 1-2 sigma bands and if there is a target particle present, its signal should become more distinct, a bump with a higher sigma.

    Of course I could be totally wrong, but it is interesting thinking about it.

18. Arun on Mar 11th, 2007 at 3:05 pm

    Paul - re -

    “A small amount of data looked at, would theoretically have less chance of a fluctuation, than a vast pool of available data?”

    To give a simple example, suppose I was trying to find out whether a coin had heads on both sides, and the only way to do so was to toss the coin and observe one of the sides. Let’s assume that the coin is fair - namely it lands on either side with equal probability.

    If I tossed the coin 3 times and saw heads all three times, it is possible that the coin landed on the same side all three times (one time out of eight trials of 3 tosses).

    If I tossed the coin 21 times, and saw heads all three times, the probability that the coin landed on the same side all 21 times is approximately 1 in 10 million, and I’d be much more confident that both sides of the coin bears heads.

19. Hal Porter on Mar 11th, 2007 at 5:19 pm

    John:

    As a sometime science writer, let me commend you on the simplicity and clarity of your post. This is a real contribution.

    Also, like others, I can appreciate the excitement and frustration that such tantalizing results offer. While most of these signals may be spurious or artifacts of some sort or just statistical anomalies, some probably really are a first manifestation of a deeper reality.

    It must be a very exciting time for all of you, especially since it seems to me that you are all a generation younger than I am.

20. Brian on Mar 11th, 2007 at 5:37 pm

    Arun - Thanks for alerting me to the article in the Times: I really enjoyed it.
    Paul Valletta - By a “bump” they don’t mean an aberration in a particular datum. As you point out, the more data, the more individual oddballs one is likely to have. By a “bump” they mean that an unexpectedly high PERCENTAGE of the data has a certain characteristic. The more data one has, the more likely it is that the percentage of the data in the sample with, say, energies between 159.0 and 161.0 GEV is close to the percentage of data with that charactreristic in the underlying population (reality) rather than being a mere statistical fluke. It makes sense that the more data one has, the more accurate one’s assessment can be. I hope that helps.

21. tyler on Mar 13th, 2007 at 3:18 pm

    As an extremely interested layperson I hope the tendency towards increased scientific discussion in (and between) blogs continues and even increases. Tommaso’s point about this discussion “filling the gap” between formal papers and the magazines is a good one. Physics papers, at least ones of value, are largely over my head; I can glean only meager understanding, and probably much misunderstanding, from reading them, though I find the effort interesting and sometimes enjoyable. Popular science written by journalists is filtered through the minds of writers and editors who, for the most part, seem to understand things much less well than even I do.

    Just as I only read “pop sci” books written by actual working scientists, having been burned one too many times, so also am I only really interested in reading online or in magazines from that same group. My own lack of rigorous understanding is more than enough filter already, without adding someone else’s ignorance into the signal chain upstream of me.

    This blog is a perfect example of the sweet spot - some posts are technically over my head (I am in the same boat as George re: your bump-hunt graph) but only partly so. I feel like I always at least grasp the essence of what’s under discussion, and the increasingly interactive nature of the discussion is quite exciting. I am more interested in the science posts than the cultural ones, though I am more qualified to comment meaningfully on the latter…;o)

    As for the open discussion being misread or spun: it’s either accept and try to mitigate the reality of that happening, or give up the discussion. Don’t do that. This, I think, is one of few areas where the blog format actually brings something new to the table. It’s a step forward.

    The future of scientific discussion looks a lot more like Cosmic Variance than it does New Scientist, or at least I hope so.

22. tyler on Mar 13th, 2007 at 3:19 pm

    “that same group” == e.g. you people

    so thanks

23. Gordon Watts on Mar 16th, 2007 at 2:28 am

    John — glad to see this post! You are actually getting quite a bit of flack over here after the NS article. I’ll point people to this.

24. Pingback from Philosophia Naturalis #8 « {metadatta} on Mar 31st, 2007 at 10:08 am

    [...] Having huge meetings and partying like rock stars isn’t everything, though. Among other things, the physics community (just like any other) has its share of scandals, politics, marketplace tactics, things of that sort. Sabine Hossenfelder, for example, has recently blogged about the problems of treating the scientific community as a marketplace, while Julianne Dalcanton’s post on physics’ “cult of genius” definitely touched a nerve among readers. Meanwhile, Clifford Johnson has shared his views on recent events regarding an imprisoned theoretical physics grad student. (And of course, there’s the media aspect of things: John Conway recently picked up on his two previous posts on the search for the Higgs boson to blog about the unexpected media response.) [...]

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