Faith in theory and curve-fitting, at least...
Tommaso Dorigo reports some new results, which are based on a figure that could be titled "Why I Am Not a Particle Physicist #729":
"What's the problem?," you ask, "There's a nice big peak there, looking a little like a black-body spectrum."
Ah, but that's not the signal. The green shaded region in the big plot is all background. The signal is in the tiny little gap between the green background line and the blue data points on the right-hand side of the enormous background peak.
Now, this is actually a pretty solid result, as you can see from the inset, which shows the difference between the data and the background, with error bars. There's a clear peak, at least 5-6 times larger than the error bars, and it's right about where they expect it (which I believe is what's indicated by the little red shaded peak in the bigger plot). I'm not saying this is a bogus result because I can't immediately see the signal in the raw data, or anything like that.
I'm just saying that I'm glad I don't work in a field where I'm trying to tease a signal that small out of a background that large. You really need to have some confidence in your measurements of the background level, and do some serious statistics to confirm that it's a real signal. I just don't have the right temperment for that sort of work...
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As I am slowly discovering, I don't have the right temperament either...
Just be glad you're not looking for polarization in the CMB -- with a signal to noise of about 1 in 10^6 -- BEFORE you add in experimental noise, atmosphere, systematics, etc.
Not sure that 'faith' is the right word for it though - 'pretty solid result,' kinda strikes faith out of the equation. Nor is the conclusion dogmatic, or accepted lightly; it is however objective and empirical.
Sorry, but after the Paul Davies NY Times article from a few weeks ago, I've been critical of the use of the word 'faith' in the same sentence of something about science, where evidence-based conclusions are involved.
... perhaps "Requires Curiosity" would have been a better choice than "Faith," as I assume the particle physics experiment started from a question or hypothesis.
Hi Chad,
thank you for discussing my result... And for the link.
I think I understand you well. It is true: these kinds of "signals" are disheartening. But it is actually much worse than that... As you see, the amount of signal in the plot is about 6000 events in 250000. But before a very carefully tuned kinematical selection, the signal - after online triggering - amounted to 20000 out of fifty million!
Actually not just that. The signal cross section is 1.1 nanobarns, while the total inelastic proton-antiproton cross section is 70 mb: that means that the initial signal to noise ratio is one in sixty millions...
I concur. I too like the nice atomic lines in a spectrum... I think those are the kinds of grab-and-go signals we should be treated with. But the harder something is, the more intriguing it is...
Cheers,
T.
As a high energy THEORIST, I would like to request that you change that sentence to "Reasons why I'm not an EXPERIMENTAL particle physicist"!!
I can tell you that MY graphs have always been perfectly smooth and convincing!
I'd just like to say that "nanobarns" is my new favorite unit of measurement. Anyone know how many nano-cows my now-sheltered bales of nano-hay will feed?
'Faith' in this Blog Post Header is indeed the wrong word, especially in the U.S. Perhaps 'Confidence in your method' would be better (but, I admit, sounds pedantic). No 'faith' nor divine revelation is required to understand the result, and if Tommasos's colleagues or other particle physicists would think this result to be wrong, they'd delight to shoot it down with specific criticism of the method. Say that about theologians!
I fear you will be much misquoted by local (to the U.S.) fundamentalists, or theologians, who like to establish faith and science as equal ways to acquire knowledge (at best) or science as equally faith-based as their religion (and then, of course, the faith from their favorite holy book and divine revelation beats un-understandable science every time!)
Or are you in the running for the Templeton Prize? (I believe not; this foundation gives money to people who equate science and religion).(No offense intended.)
give it a rest, a. it's a JOKE. You've got a sense of humor measured in nanobarns.
What blinker said, only more politely. The post title was a joke, an intended-to-be-humorous reference to the Paul Davies op-ed and other similar discussions.
I probably ought to know better than to post anything on the Internet that isn't intended to be read in the most narrowly literal way possible, but what can I say? I'm a foolish optimist.
Sorry, I didn't get the joke - but I have encountered a few biologists who are arguing in support of Davies article. I just assumed that you were doing the same.
Sometimes satire and the real thing are just too difficult to tell apart.
Two quick comments:
1) Your comments reminded me of a really ancient (it was ancient when I was in school) editorial in the Physical Review Letters (as I recall) about "bump hunting". It basically said that bump-hunting articles would be summarily rejected unless they explicitly addressed a series of validity tests. That is why their analysis has a theoretically produced background and signal that has been run through their detector monte-carlo simulation. All reasons to not do experimental particle physics unless you really like computing and the phenomenological side of theory.
1') Maybe your contacts can track down that article. My recollection is that it was in the early years of PRL. If not, see if you can track down the "High Energy Physics Coloring Book", a joke article that was published in a collection of similar stories. "There is a peak at B, color it red." I think that same collection has the article telling faculty how to make a PhD candidate spin like a top with appropriate oral exam questioning methods.
2) comment #7: The name for the unit "barn" was chosen based on the analogy "hit the broad side of a barn". A 1 barn cross section is huge, although the analogy really comes from nuclear processes that have 1000 barn cross sections: the effective area is many times greater than actual size of the object a neutron is interacting with.
Science and technology does have its limitation. There are Physics Foibles. See Godel Incompleteness.