Discuss.
?
OK.
He made a prediction, based on his beliefs about physicists.
His prediction proved incorrect.
He ought to therefore update his beliefs about physicists.
Presumably you thought this an interesting question, or you wouldn't have posted this.
Would you mind kicking off the discussion by explaining why?
Don't quite see why this is down voted. Most are probably not aware about that prediction he made, nor that he updated later. A discussion post showing him updating properly is marginally valuable.
We already had some discussion (including a comment by Eliezer) here.
EDIT: Wait, that's the same discussion linked to in the post, but in the link given there you can't see the recent discussion because the link goes to a post one generation into the comment tree.
EDIT2: Also, who cares what Eliezer thought about the Higgs? It's not at all his speciality, and he was only betting at even odds. A wrong prediction there hardly counts against him at all.
The impression I've formed is that physicists have a pretty good idea what's pretty reliable (the standard model) and what's still completely speculative (string theory) but at some point the popular science pipeline communicating the difference to intelligent scientifically literate non-physicists broke down, and so I became broadly cynical about non-experimentally-verified physics in general, when if I'd had more information, I'd have been able to make much more accurate predictions about which were very likely, and which were basically just guesses.
The title of this post tempted me to make another article called "Eliezer apparently right about just about everything else" but I already tried that and it was a bad idea.
Have you actually catalogued a comprehensive list of Eliezer's predictions, and which ones have been show correct, wrong, and indecisive?
Is he right when he says to beware cached thoughts and where he says to beware when confronting new evidence simply repeating one's pre-existing evidence and arguments rather than actually updating?
The Higgs Boson -didn't- show up. There's evidence for a particle with mass consistent with the expected mass of the Higgs Boson, but this is not the same thing as a particle with the expected properties of the Higgs Boson.
However, there's an issue: They didn't know what the mass was supposed to be. Saying that the mass was consistent with the expected mass becomes less meaningful when you add that they spent the first two years of the LHC's operation excluding possibilities for what that mass would be. It's also less meaningful when you consider that they had already detected spikes at that mass range.
So what they -really- found is a particle with a mass consistent with particles they had already observed in the LHC. They're -calling- it the Higgs Boson, but have not in fact observed the -properties- expected of the Higgs Boson.
That's not what we're saying.
We have observed a particle whose properties match what we would expect to see from the Higgs Boson at our current levels of data and sensitivity. This is not based on the value of the mass. We saw three decay modes with consistent excesses at a specific mass, and those decay modes match expected Higgs decays (H → γ γ, H → W W, H → Z Z). There are other decays that don't show an excess (H → τ τ, H → b b), but we don't expect nearly as much sensitivity in those channels yet. We excluded the other mass ranges in the same way: the sensitive decay modes in those regions did not show any excess.
There are many properties still to be analyzed, such as spin and branching ratios. There's a good post at Quantum Diaries about possible values for the spin. I actually hope the branching ratios are different from Standard Model expectations, since that would indicate a massive new particle which could be a dark matter candidate or lead to other new physics.
Stupid question. How the devil does a particle of mass 125 GeV decay to two particles of mass around 80 GeV each? What are the actual observed end products?
That's not a stupid question at all. Basically, the W and Z bosons are just virtual particles here, that decay very quickly, so that Heisenberg's uncertainty principle (∆E * ∆t ≥ ℏ/2) is satisfied. The observed end products are four leptons (i.e. electrons, muons or taus plus the associated neutrinos), which add up to a mass much less then 125 GeV – the rest is in their kinetic energy.
Okay. So they're actually talking about the 4l channel, which on theoretical grounds must involve an intermediate heavy (and virtual) boson. I opine that when the boson is virtual, ie there's no mass peak in the two-lepton spectra, you ought not to say that you've observed the '2W' channel, even if that's the Feynman diagram you draw to explain the observation.
I mostly agree with you.
One exception though: In the Quantum Diaries post Dreaded_Anomaly mentioned, I'm fine with them talking about H → W W and H → Z Z decays, because they're only talking about spin conservation at that one point – no need to mention the end products there. (But that wasn't what you were talking about, I guess.)
I haven't seen the data, or even firsthand accounts; the only thing I've seen thus far are second and thirdhand accounts, which conflict on whether or not the decay modes seen are the decay modes expected. They match in type, but not probability, and AFAIK this discrepancy, if not resolved, is a major problem in classifying the particle as the Higgs Boson; if further/better observations resolve this discrepancy, then the decay modes become evidence for it; as they exist right now, it's mild evidence against it. My inclination is to "Wait for further evidence."
(I'm accustomed to the "Higgs Boson" being evidence for Higgs Field Theory. If it turns out Higgs Field Theory, and Standard Theory more generally, is wrong, then I'd be reluctant to call it the Higgs Boson even if it's otherwise exactly the particle predicted, but generated for different reasons.)
If it turns out Higgs Field Theory, and Standard Theory more generally, is wrong, then I'd be reluctant to call it the Higgs Boson
There's different “kinds of wrong” in science, as noted by Asimov in his essay The Relativity of Wrong:
"When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."
Which of these “wrongs” did you mean?
In the Higgs mechanism, the W and Z acquire mass by pairing up with degrees of freedom from a Higgs field. (Fermions get their mass differently; a purely left-handed massless fermion and a purely right-handed massless fermion pair up into a single massive fermion via their interactions with the Higgs field, but the massive fermion does not incorporate degrees of freedom from the Higgs field into itself, the way that the massive gauge bosons do.)
A Higgs boson comes from the unused degrees of freedom of a Higgs field. In the long run, the new particle will be called a Higgs boson if, and only if, it continues to look like a degree of freedom left over from a Higgsing. So it can still be a Higgs without being a standard model Higgs; for example, it might be one of several Higgses, or its couplings to the other particles might be different from the standard model values. The fermions could get their masses in some other way entirely (e.g. by being composite), but this particle would still be a Higgs so long as it's the residue from the acquisition of masses by the W and Z. That's the aspect which has to be false, if it is not a Higgs.
I've got a meta question. This thread isn't showing up for me in discussion, main, or anywhere else I can find except on the recent posts sidebar. Judging by the timestamp, it should be right up on the top of the page, but it isn't. Can someone guess why this is? Like, is there a setting one needs to change in order to see negatively scored posts?
In addition to any score threshold you set in the preferences, posts you downvoted will not show up on the front page.
(this seems like a nice feature by the way, it reduces the attention people pay to content they don't like, which should reduce negative comments and arguments)
Edit: hum, seems this is actually an option one can set in the preferences, maybe I set it and nobody alse did.
Unrelated: This permalink to my above comment shows that it has two edits. But if you go to the original post and scroll down to the comment, only one edit appears. wtf? Is it like that for anyone else?
Not for me; I can see both edits. Edit: Either way I look at it.
Edit 2: If it's still doing it for you, try Ctrl+F5 (or whatever "force refresh" is for you) on the original post if you haven't already.
Hmmm... force refresh didn't work and nor did emptying the cache. Still, the problem is probably at my end, because the same problem doesn't happen if I use I.E. instead of Firefox. Weird.
EDIT: Fixed it, it was my problem. (It was RIP being weird, which is worrying, but nothing to do with LW.)
So someone told me that Eliezer Yudkowsky predicted no 5 sigma evidence of the higgs boson, and that 6 sigma evidence had been found. A quick search found the post referred to, and a slightly longer but not particularly thorough search did not find anything discussing it.
So:
http://lesswrong.com/lw/1dt/open_thread_november_2009/17xb (02 November 2009)
I'll go ahead and predict here that the Higgs boson will not be showing up. As best I can put the reason into words: I don't think the modern field of physics has its act sufficiently together to predict that a hitherto undetected quantum field is responsible for mass. They are welcome to prove me wrong.
(I'll also predict that the LHC will never actually run, but that prediction is (almost entirely) a joke, whereas the first prediction is not.)
Anyone challenging me to bet on the above is welcome to offer odds.
In the post below rolfandreassen sets the condition of 5 sigma evidence before 2014 and offers a bet of $25. In the post below that Eliezer accepts.
Discuss.