Two independent teams working on the existence of something that matches the Standard Model Higgs boson managed 5 sigma and 4.9 sigma that the result was evidence of a particle that matched the theory and not the result of null hypothesis.
WTH does that mean, anyway?
Standard deviation is a way to break up the bell curve into even chunks along the x axis of the curve based on the data points. Take a bell curve in your mind. Standard deviation is calculated by taking the average of all of the data points in the set, then subtracting each data point from the average, and squaring the results. The squares are then averaged against the data set and the result is the standard deviation.
Okay, that gives us a standard deviation and that's what sigma is. It is the number of standard deviations from the top (most probable result) of the bell curve out to wherever the ends of the curve are (least probably results). In our minds eye bell curve, generally two standard deviations either way gets you out to the small areas of the curve. 5 would take you a long way out from the centre.
Now, that's all nice and everything, but what about the null hypothesis? In each test you start off with a basic default assumption and that if you see it based on previous knowledge you will recognize it and therefore invalidate the test results. In all the tests in the Hadron Collider they see random noise, they can recognize it and so if in the Higgs boson test they saw stuff they recognized previously that would have invalidated the results of the test. It matched a null hypothesis. (Note, I have no idea what null hypotheses they used, so the above is a WAG.)
So, basically they tested a bunch of times to get a data set, they examined the data set and the results seemed to indicate the presence of something that
- matched what the Higgs boson is theoretically supposed to be,
- had a 0.0000003 (sigma 5) probability of matching what they decided would invalidate the results.
And yet, the physicists are being extremely careful in not saying they've found Higgs boson....
Remember that when you read stuff like this from the IPCC:
| Confidence Terminology | Degree of confidence in being correct |
|---|---|
| Very high confidence | At least 9 out of 10 chance |
| High confidence | About 8 out of 10 chance |
| Medium confidence | About 5 out of 10 chance |
| Low confidence | About 2 out of 10 chance |
| Very low confidence | Less than 1 out of 10 chance |
Haven't got a clue about this stuff, but I'll tell you.......I'm sure impressed!
Yeah - a lot of (sad) experience has shown that at the 95% confidence level something becomes interesting, at 99% confidence level you can begin to pay attention to something, at 99.9% it might actually be real, but don't believe it.
9 chances in 10? That is another word for s**t.
One of the reasons for this skepticism is that 1) errors probably aren't Gaussian; 2) you don't know what the actual distribution of uncertainty is.
It is a good idea to read Nessim Taleb's writings about the horrendous errors into which the assumption that economic and financial time series are Gaussian has led.
The physicists are saying a Higgs-like boson, because there still is some uncertainty.
http://www.bbc.co.uk/news/world-18702455
"Last December, the twin Higgs-hunting experiments at the LHC – CMS and ATLAS – reported shards suggesting a Higgs with a mass of around 125 gigaelectronvolts, but they were not statistically significant enough to claim a discovery. The convention is to declare victory when the statistical significance of a particle’s signal is 5 sigma, meaning the chance of something else producing it is less than one in a million. December’s signals were each about 2 sigma."
The 5-sigma significance was obtained by combining 2 data sets.
Also this particle needs to act like what a Higg's bosun is supposed to act like.
The ways in which the new particle interacts with other particles is consistent with what was expected for a Higgs boson, although further measurements will need to be made to pin down its identity. In particular, physicists will want to determine whether the new boson has zero spin as predicted, according to Incandela.
The way in which the new particle decays into other particles will also be key to verifying its precise nature. Already, the new boson seems to be decaying slightly more often into pairs of gamma rays than was predicted by theories, says Bill Murray, a physicist on ATLAS, the other experiment involved in making the discovery. But, he is quick to add, the data are still very preliminary.
http://www.nature.com/news/physicists-declare-victory-in-higgs-hunt-1.10940
Imagine biology working the same as theoretical Particle Physics:
I am sure that dogs exist. I have never seen a dog. However if a dog existed it must have 4 legs, a tail and two ears. Let me do some experimenting. AHA I have found a dog. It has four legs, a tail and two ears. In fact I can now definitively state that dogs make a MOOOO sound when they communicate. Of this I am 90% certain.
The eco-cultists don't use probabilities.Their models say everything they want them to say is 100% probable(well,to fellow cultists and stupid politicos)And the null hypothesis? Oh yeah.They use that one to remove ANYTHING that even at 0.00000000000001% might disagree with consensus.
CERN holding back on any announcement( like they did with the faster then light thingie,which they then corrected) is what REAL science is about.
Saying that you are confident within 5 sigmas is nonsense.
It only measures those uncertainties that you are aware of. It does not take into account your own ignorance -- in other words, those things that you don't know you don't know.
And that, rabbit, is why the IPCC is Central HQ for the world's Climate Scientologists.
The 5 Sigma certainty DOES take into account ignorance. That is the best part of physics: everything is very well defined. The statement is not "We are 5 sigma certain we've found the God Particle, what ever that may be."
The statement is " We have decided that a Higgs Boson should have these 10 features (this number is just made up). We found a signal that has these features to 5 Sigma certainty."
Going forward, every physicist examing this new particle keeps this definition in mind. They are free to find more features, propose changes to the definition, and get nearer to understanding what they have found.
However, Reporters like very direct statements.
Fred R.:
"That is the best part of physics: everything is very well defined."
Did they take into account that one (or a few) of the researchers could have found a way to fake the results for their own amusement? How well defined is that possibility? How well defined is the possibility that the Standard Model is seriously wrong, and that they are completely deceived about what they detected?
In any human endevour, there is no such thing as "everything accounted for." Not in science, not in anything.
All those probabilities they are talking about are pretty much meaningless unless they properly take into account the probabilities associated with the failure modes of the gazillion different components of their equipment. Recall that it only took 2 (two!) malfunctioning pieces of equipment to cause them to observe that neutrinos travel faster than the speed of light! But as long as they get results that everybody likes, no one is worrying about possible artifacts of equipment malfunction.
I have a post here about the neutrino debacle, and the skepticism it should cause.
Also, if their observations are what the Higgs Theory predicted, then what if these observations had not occurred? In this case they would have announced the non-existence of the Higgs boson, right? Of course not! They would have fiddled with their equipment, they would have kept trying, etc. If these people were serious, they would have announced something like: "Tomorrow we will start an experiment to determine if the Higgs Boson exists. After two months of collecting data, we will have the answer, one way or the other."
@LTEC - Actually, last December they did say they were 95% sure the Higgs Boson didn't exist, and that in 2012 they would determine a relatively firm answer with very high confidence one way or another.
K Stricker --
Thanks for this info -- I didn't know that. (Can you give me a link?) Was the data that led to the 95% disbelief in the Higgs boson included in the experiments they just reported, or did these new experiments just start over? And how did they decide when the experiments should end? It would have been nice to have told us in advance exactly when the experiment will begin and exactly when it will end, and to have scheduled their press conference in advance.
And when are physicists going to start doing proper error modelling of their equipment? We know they weren't doing this before last September when they were trash-talking about neutrinos.
The first thing that popped into my mind was " so what?".
I've been reading much of the afternoon, and have yet to come up with an answer.
rabbit - Good point about the idea and practice of controlled experiments. It seems likely in this hairball, there " is no such thing as "everything accounted for." So the result is weak, or tentative confirmation, after which physicists will have a bias towards belief the particle exists, but they will seek further confirmation. I wonder whether the rest of the experimental physics community considers these results as proof.
Help me out here, when you say, "...had a 0.0000003 (sigma 5) probability of not matching what they decided would invalidate the results"
My universal translator is on the fritz. If they have a (really small number) low chance of NOT matching that which would invalidate the results, doesn't that mean that it is a (really big number) strong chance that they have gotten the kind of results that would invalidate the tests.
It must be all of the double negation that is throwing me...I used to have a professor who would give multiple choice questions that would be worded like, "All of the following are almost always not false except..."
Good Discussion on the discovery is here:
http://physicsworld.com/cws/article/news/2012/jul/05/its-a-boson-but-what-sort
@LTEC - Sure, I guess it was last August they announced the 95%, they had already seen some signs of it in December.
CERN announces 95% certainty of the non-existence of Higgs Boson
I can't seem to find an old article referencing the "finding or ruling it out in 2012" line, so it may have been a little revisionist history in one of the newer reports.
Ah, here's a reference to the found or ruled out. Good thing I didn't try to give a confidence level on my last post ;)
It is quite possible that they have detected something (particles) with the energy/mass expected of the Higgs Boson but it not be the Higgs Boson.
Further testing and data collection and additional experiments could possibly elucidate this issue. The Higgs Boson should have certain unique properties (don't know what) and these could be tested.
Thanks Bryceman, the gobbledygook got me.
Bah! Equipment malfunction is what gives experimentalists sleepless nights. The article was about random error. Yes, there is also systematic error, and no one will call the Higgs
really truly discovered until it is demonstrated in two different ways.
How do you report a non-result? It goes more or less as follows: "after examining [a gazillion] decays our results are consistent with the null hypothesis within ... limits."
In the case of proton decay it was possible to extract a lower limit to the lifetime: "our experiments show that the lower limit to the lifetime of the proton is 10^29 years" or thereabouts.
In molecular physics one usually just says, "we looked and we didn't find anything" - less highfalutin but the experiments are less expensive.
What we have here, are some very nervous physicists who had best provide SOME hope that their $10 BILLION experiment was not a total failure.
They could easily go from chumming with Hawking, to hawking chum.
The LHC is an awesome machine. With an awesome data collection and storage system. The data are to be archived indefinitely, and will be re-examined by anyone who wishes. This is what is done also with astrophysical satellites, and yielded big dividends e.g. with IRAS (InfraRed Astronomical Satellite).
Daddy, why isn't the King wearing any clothes?
Higgs postulates a 'particle' and another group of scientists build a billion dollar etch-a-sketch and draw a picture which they claim is Higgs 'particle'. Nice scam.
What's next, pictures of the Yeti.
Make the scam big enough and obscure enough and millions will fall for it.
north_of_60, you have been jaded by the Crimatology scam; this is no scam. The world of particle physics is one of the most accurately measured in all physics.
John Lewis, can we then state that the proton is stable?
I'm with eastern paul on this. Don't understand SFA
but am suitably impressed. I guess bullshit really does baffle brains.
6 sigma is a pretty good deviation rating for a manufacturer but for establishing a mathematical/scientific conjecture as fact it is oppertunity for error as vast as space. Mathematical fact must be repeatably provable infanitum.
As the inventor of the Biggs' hoson, I would just like to say, send the Pobel Nrize to this address:
Hardley Human,
Obviously Not in Canada,
Must be some kind of foreign-born Alien.
Thank you.
Robert of Ottawa, no, we can't say that the proton is stable, just that if it decays it decays very very slowly. So not to worry. But it is entirely possible that in the very distant future there will be no more protons (hence no more matter in the form we know it).
Protons might be stable, or they might be like bismuth-209 and tellurium-124, which were thought to be stable but were caught decaying (sneaky bastards). Tellurium-124 has a half-life of 2 times 10^24 years.
The Kamiokande detector in Japan was built to discover proton decays. It didn't find any, but was useful in observing cosmic neutrinos. Perhaps better than proton decays!
Robert of Ottawa at July 5, 2012 6:39 PM
"The world of particle physics is one of the most accurately measured in all physics."
May Odin have mercy....
March 1, 1954 the US wunderkind had such confidence.....when they set up a little test called "CASTLE BRAVO."
The yield of 15 megatons was two and a half times as great as expected. The cause of the high yield was a theoretical error made by designers of the device at Los Alamos National Laboratory. They considered only the lithium-6 isotope in the lithium deuteride secondary to be reactive; the lithium-7 isotope, accounting for 60% of the lithium content, was assumed to be inert.
It was expected that lithium-6 isotope would absorb a neutron from the fissioning plutonium and emit an alpha particle and tritium in the process, of which the latter would then fuse with the deuterium and increase the yield in a predicted manner. Lithium-6 obeyed this assumption.
However, when the lithium-7 isotope is bombarded with energetic neutrons, it captures a neutron then decays yielding an alpha particle, a tritium nucleus, and the captured neutron. This means more tritium was produced than expected, and the extra tritium is fused with deuterium. In addition to tritium formation the extra neutron released from lithium-7 decay produced a larger neutron flux. This caused more fissioning of the uranium tamper and increased yield.
This resultant extra fuel (both lithium-6 and lithium-7) contributed greatly to the fusion reactions and neutron production and in this manner greatly increased the device's explosive output. The test used lithium with a high percentage of lithium-7 only because lithium-6 was then scarce and expensive; the later Castle Union test used almost pure lithium-6. Had more lithium-6 been available, the usability of the common lithium-7 might not have been discovered.
The result was the safe distances etc were just a bit too close.
This was like the inadvertant discovery of the EMP effects of a high altitude detonation....when one of the ABLE/BAKER series knocked out the street lights in Hawaii, 1500 miles away.
"And yet, the physicists are being extremely careful in not saying they've found Higgs boson...."
If they claimed to have found it, who would continue to fund their research?
Higgs was noted to say, after wiping away his tears of joy, "At least it wasn't asymptotic".
Disproving habitue within several sigma of proscribed energy levels is more important than having sigma, especially at these microchronal, unstable, high energy levels.
Not that I don't like to see two perfectly good particles hit each other like car racing.
Could the Standard Model Higgs boson"particle" exist only as .....IDEA?
Like MAN ......an idea in God's MIND?
.......Just a high school dropout's mulling the Higgs boson thingy!
K Stricker at July 5, 2012 5:22 PM - From the article you linked to: "CERN scientists declared that over the entire range of energy the Collider had explored—from 145 to 466 billion electron volts—the Higgs boson is excluded as a possibility with a 95% probability."
From that I gather that they didn't find it WHERE THEY LOOKED but the possibility of looking elsewhere remained--although there might not have been too many of those places left.
"Crimatology scam"
LOL too perfect a name, and has done more damage to science in general than it has to the budgets of countries who have fallen for it.
Theoretical particle physics and the experiments done to verify or dispute those theories involve extremely complex maths and huge machines. It is completely separate from the climate scam which is all "Shut up!" and "Listen to me!" with no evidence whatsoever, designed to brainwash the masses. It's based on computer models and cherry picked data.
In this situation, they figure they must have found something, they say it *could* be the Higgs Boson and it could be something else. They are being very cautious about saying anything because they are combining 2 data sets and are themselves saying that that *proves* nothing.
That said, they are smashing atoms together at incredible speeds - what else could be causing these results? When they say it's extremely unlikely for something to be interfering with their results they aren't kidding.
"one (or a few) of the researchers could have found a way to fake the results for their own amusement?"
It would be a damned shame if that were possible in experiments at this level. I highly doubt it - I would imagine a lot of people would have to be "in" on it.
pok:
The first thing that popped into my mind was " so what?".
I've been reading much of the afternoon, and have yet to come up with an answer.
Yep, and in 1905, reading Einstein's paper, the first thing that popped into many minds was "so what"?
The answer came to them in a blinding flash about 40 years later at Hiroshima.