13 replies to this topic

[Black Wolf]

http://johncostella....ino-blunder.pdf

TL;DR

OPERA claims that they found that neutrinos could exceed the speed of light, even accounting for statistical and systematic errors. John P. Costella claims that their fit wasn't tight enough, and that the neutrinos were actually going at a speed less than the speed of light, if properly accounting for the statistical and systematic errors.

[Steve D'Ippolito]

Suggest merging this with http://forum.objecti...=0

(No I am NOT beating on you for failing to use the search function as some people here are wont to do [I personally have found it worse than useless at times]--the title of the thread I am linking to isn't obviously about this subject. I just happened to notice there was another discussion of this.)

[Grames]

http://johncostella....ino-blunder.pdf

TL;DR

OPERA claims that they found that neutrinos could exceed the speed of light, even accounting for statistical and systematic errors. John P. Costella claims that their fit wasn't tight enough, and that the neutrinos were actually going at a speed less than the speed of light, if properly accounting for the statistical and systematic errors.

John P. Costella merely makes the case that the results are not 6-sigma reliable, only 2 sigma. He may have a point, but it is hardly a refutation. 2 sigma still exceeds 95% confidence in the results.

[Black Wolf]

Suggest merging this with http://forum.objecti...=0

(No I am NOT beating on you for failing to use the search function as some people here are wont to do [I personally have found it worse than useless at times]--the title of the thread I am linking to isn't obviously about this subject. I just happened to notice there was another discussion of this.)

Well, my knowledge of physics is limited.. I wouldn't have known to seek that particular thread out, because I don't know what "Group theory" is. Still, I feel it warrants it's own thread, because it's quite a controversy in itself.

Grames, your post has actually helped me understand this article better, believe it or not. What is the difference between 2 sigma and 6 sigma? The extent to which power you raise each individual value (summed) minus the mean raised to said power?

Edited by Black Wolf, 24 September 2011 - 11:45 PM.

[Grames]

Grames, your post has actually helped me understand this article better, believe it or not. What is the difference between 2 sigma and 6 sigma? The extent to which power you raise each individual value (summed) minus the mean raised to said power?

Good question, and I miscounted in my earlier answer. 2 sigma's are 68%. I got confused from counting sigmas away from the mean in one direction (and then doubling) instead of recalling 2 sigmas refer to the total span in both directions.

See standard deviation. In the diagram below, the six sigmas referred to are the span from -3 to +3 sigmas. Two sigmas are from -1 to +1 sigma, the darkest blue region.

Edited by Grames, 25 September 2011 - 03:42 AM.

[Tensorman]

Costella has now withdrawn his criticism, the link is the same one: http://johncostella....ino-blunder.pdf

[th3ranger]

If anything were to do something this strange it would be a neutrino. Damned things are very very strange. They basically interact with matter at a very low rate, almost not at all. This is because they are very low in mass and are neutral in electrical charge. One time a friend and I calculated for fun its 1/10 thickness in lead (the thickness at which a given amount of a specific type of radiation will be reduced to 1/10 of its original energy) and it came out (roughly this is by memory) 600,000 miles of solid lead, or, roughly, from the earth to the moon in lead. We laughed about this for a good ten minutes. The usual tenth thickness for any other radiation is measured in inches or feet.

So, if any radiation were to go faster than the speed of light by accident, it would be a neutrino. I'm not going to think much about this finding until it is verified by being replicated. It does make you wonder... if neutrinos can exceed the speed of light maybe a spacecraft could be induced to go fasted than light... :-) (but it was, I think, probably, some sort of mistake.)

[Steve D'Ippolito]

If anything were to do something this strange it would be a neutrino. Damned things are very very strange. They basically interact with matter at a very low rate, almost not at all. This is because they are very low in mass and are neutral in electrical charge. One time a friend and I calculated for fun its 1/10 thickness in lead (the thickness at which a given amount of a specific type of radiation will be reduced to 1/10 of its original energy) and it came out (roughly this is by memory) 600,000 miles of solid lead, or, roughly, from the earth to the moon in lead. We laughed about this for a good ten minutes. The usual tenth thickness for any other radiation is measured in inches or feet.

Agreed, neutrinos are oddball little particles! To put what you just said in a more concrete form: They slip through thousands of miles of rock as if it is nothing (you are being bathed by solar neutrinos even at midnight--and the full thickness of the earth doesn't attenuate the beam measurably). They can switch from electron to muon to tau flavors--though you don't see _electrons_ doing that trick terribly often! I agree that if something is going to up and behave oddly (I almost said "strangely" but remembered "strange" has its own meaning in particle physics), it's the neutrino. Or antineutrino as the case might be. (I'd guess there are more of those zipping around harmlessly, even though they are technically antimatter, than neutrinos since they are made by the process of stellar fusion.)

I've actually seen much, much higher figures for the tenth thickness of a neutrino at times (on the basis of, neutrons having a half life of ~12 minutes, so a neutrino would have to be inside a proton that long before it would have a 50 percent chance of being absorbed; at approximately light speed the neutron would go through a LOT of protons in 12 minutes (about 720 million miles' worth, strung end to end), but recall that matter is mostly empty space and very little of it, volume wise, is protons. So I generally see claims that the half thickness (much less the tenth thickness) being on the order of light years.

However, they do occasionally interact after they are created, so it IS metaphysically possible to die of neutrino radiation poisoning. Apparently if one were to be within a billion miles or so of a supernova the neutrinos (the vast majority of the energy from the supernova) would kill you before the electromagnetic radiation and the blast wave could get to you, simply because there are so doggone many of them that their standoffishness is more than made up for.

[Black Wolf]

Good question, and I miscounted in my earlier answer. 2 sigma's are 68%. I got confused from counting sigmas away from the mean in one direction (and then doubling) instead of recalling 2 sigmas refer to the total span in both directions.

See standard deviation. In the diagram below, the six sigmas referred to are the span from -3 to +3 sigmas. Two sigmas are from -1 to +1 sigma, the darkest blue region.

Ah, tha'ts why I was confused. Yeah, I'm farmilar with the normal distribution curve... so 6 sigma would be from -3 sigma to 3 sigma?

[th3ranger]

"So I generally see claims that the half thickness (much less the tenth thickness) being on the order of light years."

That seems a bit high...

[Steve D'Ippolito]

From the website of the Supernova Early Warning system (http://snews.bnl.gov...i/neutrino.html):

"The Neutrino is a subatomic particle famous for its ability to slip through matter without interacting. Neutrinos have none of the "handles" by which most other particles affect one another: no electric charge, almost zero mass. They are so elusive that a light-year of lead, nine and one-half trillion kilometres (six trillion miles) would only stop half of the neutrinos flying through it."

..and these folks work with the little slippery ones daily so they ought to know.

Think about how far a neutrino would have to travel through the universe (which is mostly vacuum) to encounter enough matter to be the equivalent of half a light year of lead, and thus have had a fifty percent chance of being absorbed. The vast majority of our solar system (about 15 billion KM across) is empty space, the few objects in it contributing less than two million km of thickness if lined up end to end )which they aren't) and not made out of lead... and the solar system is downright dense compared to intergalactic space. Something tells me the answer to how far a particle must travel before encountering a light year of lead-equivalent is quite likely millions if not billions of times the age of the universe.

The overwhelming majority of neutrinos that have ever been created are still out there.

[FeatherFall]

Hey there, science nerds. Since the SoL barrier seems to have been breached, it seems like an appropriate time for me to ask the following question again. Have any of you heard of tempo field theory? If so, what do you think? If the theory is correct, the speed of an object is only limited by its fuel.

http://www.tempofieldtheory.co.uk/

Tempo field theory posits that light speed changes at the speed of approach, so it is always going faster than its observer, but that matter has no maximum speed relative to other matter. Therefore, neutrinos aren't very special with regard to their maximum speed.

[Prometheus98876]

FeatherFall : I have had a little look at the link you provided. Until I have a much more in depth look at the thing and try to match it better with what I know , it is hard to say if it is "better" than the "Standard Model(s)". Though I notice that it too seems to reify time. Which is a major mistake modern physics as it is tends to make. In fact, as far as I can tell from a cursory glance, time is even more crucial to this theory than in many others.

When in fact, t ime is a measurement [ of motion] , a relational concept : http://aynrandlexico...xicon/time.html

Well, for better or worse, it is interesting anyway.

Edited by Prometheus98876, 26 October 2011 - 04:04 PM.

[Boydstun]

Loose connection looks to be source of the anomalous experimental result.