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RIP Higgs Boson (with 95% confidence)

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131–140 of 153 posts

Re: RIP Higgs Boson (with 95% confidence)

#131

Earlier quoted context omitted.

Bayesian inference is applicable here, because we are talking about the subjective probability - ie, confidence - that one single fact is true. There is no way to reduce a single "event" (that there is Higgs particle or there isn't) to a frequentist, or "objective", probability. As you correctly say, the influence that the results we already got about the possibility that Higgs boson exists with a high mass have on t…

I'm not saying Bayesian inference isn't applicable, I'm just cautioning against an careless interpretation of its results. But if you insist on interpreting it in this way then yes, it means the probability of finding a Higgs is lower. However, as I said above the term "95% confidence" is not related to this reasoning at all. Saying for example "the Higgs mass is not 140 GeV at 95% CL" means precisely: If the Higgs w…

Of course not, but we should discount our belief that the Higgs has a mass at 140GeV by a factor roughly proportionate to the 95% confidence of the result. And I don't think anyone in this thread was actually claiming that we are 95% sure the Higgs is not at 140GeV, that's usually precisely the sort of mistake that relying on Bayesian methods helps you avoid.

Re: RIP Higgs Boson (with 95% confidence)

#133

I'm a particle physics grad student. My god, what utter nonsense. The only reasonably accurate paragraph is this: "And, more importantly, the lower energy range from 114 to just under 145 billion electron volts, a region of energy that Fermilab has determined, through earlier experiments, may harbor the Higgs, has not been ruled out. But the Higgs is quickly running out of places to hide." The region of higher Higgs…

The article did not hide any of these facts though, so it's not "utter nonsense". The title of the original article is "A Higgs Setback: Did Stephen Hawking Just Win the Most Outrageous Bet in Physics History?", nothing like "RIP Higgs". The article, at best, is trying to be provocative. But, more importantly, you believe in god?

Re: RIP Higgs Boson (with 95% confidence)

#134

Earlier quoted context omitted.

I'm not saying Bayesian inference isn't applicable, I'm just cautioning against an careless interpretation of its results. But if you insist on interpreting it in this way then yes, it means the probability of finding a Higgs is lower. However, as I said above the term "95% confidence" is not related to this reasoning at all. Saying for example "the Higgs mass is not 140 GeV at 95% CL" means precisely: If the Higgs w…

Of course not, but we should discount our belief that the Higgs has a mass at 140GeV by a factor roughly proportionate to the 95% confidence of the result. And I don't think anyone in this thread was actually claiming that we are 95% sure the Higgs is not at 140GeV, that's usually precisely the sort of mistake that relying on Bayesian methods helps you avoid.

    "we should discount our belief that the Higgs has a mass at 140GeV by a factor roughly proportionate to the 95% confidence of the result"
I'm sorry but I don't understand what this means in practice. The first part is a Bayesian belief, while the 95% confidence result comes from frequentist analysis. I'm not sure how you can mix the two.

Re: RIP Higgs Boson (with 95% confidence)

#135

I'm a particle physics grad student. My god, what utter nonsense. The only reasonably accurate paragraph is this: "And, more importantly, the lower energy range from 114 to just under 145 billion electron volts, a region of energy that Fermilab has determined, through earlier experiments, may harbor the Higgs, has not been ruled out. But the Higgs is quickly running out of places to hide." The region of higher Higgs…

"The goal of X is to teach us about the world, not stroke Ys' egos and tell us how clever our existing theories are."

This a million times. I want this on a shirt, with the millions of X's and Y's it satisfies. Thank you for posting.

Re: RIP Higgs Boson (with 95% confidence)

#136

Earlier quoted context omitted.

It's completely relevant if your point is that we nickel-and-dime essential scientific funding but spare no expense when killing brown people across the globe. You don't have to go to too much effort to understand that's what the grandparent was driving at.

Your definition of 'essential' and my definition of essential are vastly different, and we are both very interested in science. Imagine the difference between your definition and most Americans who wind up paying for the thing. I personally would rather see the $8 billion go to medical research or energy research with a closer time horizon than physics research.

Personally I don't have a very strong opinion on where the funding should go at all, just that it should exist and that it should be increased by an order of magnitude at least. Even experts in a field can have a hard time deciding where to allocate resources, what hope do I have? And more importantly what the hell business does Congress have providing for these allocations? They don't know shit.

I would rather shovel billions at universities with little more than an unenforced request that they spend it on pure research, than allow Congress any control over scientific funding at all.

Mainly I just think that drawing attention to scientific funding as some kind of waste of taxpayer money when it is such a drop in the bucket is more about serving the interests of the American conservative establishment in villainizing intellectuals than actually solving a problem.

Re: RIP Higgs Boson (with 95% confidence)

#137
post #20

Earlier quoted context omitted.

At the median United States income of $40,000/year, a single billion dollars is 25,000 person-years of work dedicated solely to that billion dollars. Multiply as appropriate. Nine billion-ish in this case, according to Wikipedia. Asking what we (the human race) got for nine billion dollars (225,000 person-years of work, at a generous 50 years in the workforce the life work of 4,500 people) deserves more than glib gen…

Are you aware that we might not have had the Internet if it wasn't for government funded research? How much has your quality of life improved as a result of this? What if these advanced particle accelerators reveal that we understand physics incorrectly (which would be the case if the Higgs doesn't exist)? What if, for instance, we discovered that faster-than-light travel is possible through portals that we can const…

More glittering, glib generalities, by the way. You reach for FTL by the fourth sentence of your post; this is not a sign of strength, it's a sign of desparation. This is not a compelling, practical argument. This whole line of argument is just Pascal's Wager, with "scientific discoveries" instead of "heaven", and roughly as compelling from a logical point of view.

Re: RIP Higgs Boson (with 95% confidence)

#138

I'm a particle physics grad student. My god, what utter nonsense. The only reasonably accurate paragraph is this: "And, more importantly, the lower energy range from 114 to just under 145 billion electron volts, a region of energy that Fermilab has determined, through earlier experiments, may harbor the Higgs, has not been ruled out. But the Higgs is quickly running out of places to hide." The region of higher Higgs…

I'm not sure I follow your first argument. The probability of finding the item in the remaining 5% of the search space is independent of the time required to search different sections of the search space (unless of course you have additional prior information about where the item is more likely to be located). The fact that it may take you, say, 90% of the time to search a particular 10% section of a search space doe…

It's a little more complicated, but "all" the energies ranges are searched in parallel.

It is easier to discard the ranges that are very far from the mass of the Higgs' boson. So initially the expected range is very broad, something like:

* More than 114GeV, because if it's smaller we would have seen the Higgs boson in another smaller accelerator (LEP)

* Less than 185GeV, because we saw small corrections that are probably due Higgs boson in the (LEP)

So you get a lot of money to build another accelerator, and you are confident that the maximal energy of the collider is enough to see something.

In some ranges, the experiments doesn’t show anything interesting, so it is possible to discard that the mass of the Higgs boson is in that range. It is easier to do this when the range is more far away from the "real" value. So you can discard with a 95% of confidence that range, get some papers published, perhaps a few Ph.D. thesis, compare the data to another more indirect calculations, show some progress, and ask for more money because the accelerator is really big.

The problem is that some energy ranges are more difficult to test, because other well known particles appear but the final results is very similar to what is expected from a Higgs boson. So it is important to choose some strange phenomenon where there is easier to see the difference between a Higgs boson and another particles. So with more experiments you can discard with a 95% of confidence a new range, ..., because the accelerator is really big.

But some ranges are more difficult to discard. There are a lot of interesting phenomenons. Some of them are due to other particles. The other particles are well known, so it is possible to calculate how many of these are expected to appear sadistically. But the experiments show that there are more than expected. It can be a statistical fluke, or it can be corrections that appear because the mass of the Higgs boson is near that range. The real problem is that if the Higgs boson really exists, a lot of corrections appear in the nearby mass ranges, so these ranges are more difficult to discard with a 95% confidence ...

The most difficult range is the one that includes the actual mass of the Higgs boson. It should be impossible to discard :). But it is not enough to not be able to discard it with a 95% confidence, because it can be a statistical fluke. To "prove" that the Higgs boson exists wits a 99.99997% confidence, more and more experiments are necessary to see the difference between a statistical fluke produced by the background process of the other particles and a real signal produced by the Higgs bosons. So you need more time to find it where it really is, than to discard it where it isn’t. (So you need more money to run the accelerator, so you need to dhow some preliminary results.)

So, next year we will probably see something like "RIP^2 Higgs Boson, 99% of the initial search range discarder forever with 95% confidence, only a minuscule 1% remaining." and it will be really a good new. And in a few (5?) years something like "Zombie Higgs Boson found, returned from 99.9% dead." and it will be a really good new.

Re: RIP Higgs Boson (with 95% confidence)

#139
post #89

Earlier quoted context omitted.

I am reminded of an observation made by my former boss, a planetary scientist at NASA, about that same statistical effect: When a new Earth-crossing asteroid or comet is discovered, it's orbit is rarely known with any great certainty. The cross sectional area of the Earth divided by the area of space the object might possibly pass through yields the chance of a collision. With each successive night of observation, th…

"It's truly sad, and perhaps even criminal that journalists, and especially science journalists fall victim to those same misconceptions." "Journalists"? You are being moderated in your high praise of 'journalists', that is, professional members of the highly professional journalistic profession? Cruel. SO cruel. How can you be so CRUEL? I mean, while we're discussing particle physics, don't you believe that the Engl…

Gee, some people really do NOT like facetious comments, parody, and humor! What is it particle physicists: Don't understand humor?

Re: RIP Higgs Boson (with 95% confidence)

#140

Earlier quoted context omitted.

Of course not, but we should discount our belief that the Higgs has a mass at 140GeV by a factor roughly proportionate to the 95% confidence of the result. And I don't think anyone in this thread was actually claiming that we are 95% sure the Higgs is not at 140GeV, that's usually precisely the sort of mistake that relying on Bayesian methods helps you avoid.

"we should discount our belief that the Higgs has a mass at 140GeV by a factor roughly proportionate to the 95% confidence of the result" I'm sorry but I don't understand what this means in practice. The first part is a Bayesian belief, while the 95% confidence result comes from frequentist analysis. I'm not sure how you can mix the two.

The difference is that frequentist practice would be to stop at the 95% confidence interval and leave it there, whereas a Bayesian would use that observation to update their probability estimate of the theory being true.

"If the Higgs were at 140 GeV, it would have 5% probability of producing the results we measured experimentally" is the same as P(Observation | Higgs at 140Gev) = .05

So we can say that

  P(Higgs|Observation) = P(Observation|Higgs) * P(Higgs)
                         -------------------------------
                         P(Observation)
So given that getting your new belief about the probability of a Higgs Boson at some energy is going to be updated based on your observation, you can see that it ends up being scaled by that exact confidence result. That's sort of an oversimplification, since really you end up calculating the P(O) scaling factor based on P(O|H) among other things, but I hope you can see how they're closely related in practice.
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