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Neutrino Oscillations
This post is a followup to comments made by Bjoern Feuerbacher in another
thread. The other thread was getting terribly long - and was on another subject (the book, The Big Bang Never Happened, and Ned Wright's webpage on same). Bjoern: "Neutrino oscillations are clear evidence for neutrino masses." greywolf42: Neutrino 'oscillations' are postulated to explain a discrepancy between theory and observation. Bjoern: When you say "theory", do you mean the standard solar model? No. I mean the theory of the operation of the SuperK and neutrinos that pass through the Earth. If yes, then you are wrong - neutrino oscillations weren't postulated only because of the observations of solar neutrinos which contradicted this model. Good thing that I wasn't referring to the solar model. And today, this discrepancy has disappeared: when measuring *all* neutrinos (the SNO measurements), it turns out that the result agrees well with the predictions of the solar model. That wouldn't explain the discrepancies that *existed* in other detectors. Got a reference for 'the SNO measurements'? My detailed information was all design (1993, "Neutrino Astrophysics," Bahcall). In 1997, "Unsolved Problems in Astrophysics," Bahcall and Ostriker, ed, there are "three solar neutrino problems:" 1) Calculated versus observed chlorine rate, 2) Incompatibility of Chlorine and Water (Kamiokande) experiments, 3) Gallium experiments: No room for 7Be neutrinos. Bjoern: "Do you have another explanation for neutrino oscillations which fits all of the data?" greywolf42: "Neutrino oscillations ARE a theoretical explanation. Not data." Bjoern: "O.k., then let's word it in another way: Do you have another explanation, besides neutrino oscillations, for the experimental facts that 1) Superkamiokande measured more atmospheric neutrinos from above than from below, with a systematic dependence on zenith angle, and 2) the total neutrino flux from the sun matches nicely the predicted electron neutrino flux from the standard solar model? There are some more experiments which show similar things, but these are the best known." I think you somehow garbled #2. Read it again, and let me know if you really meant it just that way. Let's limit the discussion to the SuperK (#1), for now. Be advised that my understanding of the SuperK experiments on 'neutrino oscillation' comes solely from a Scientific American article, a couple of years back. I haven't stirred myself to more serious study of the experiment. I'd appreciate hearing your personal favorite reference of same, so that we can work from the same pages. My primary recollections of the experimental problems in SuperK were as follows: 1) The discrimination between an electron Cerenkov ring and a muon Cerenkov right was totally subjective (qualitative, not quantitative). Narrow rings (those with a vertex originating near the detection wall) would be almost impossible to differentiate. The dependence of the result upon this discrimination was quite strong. Should this human discrimination be in error by as much as only 10% (which is easy to do) the 'effect' would have disappeared. 2a) The dependence on zenith angle was assumed to mark a difference in distance travelled through the Earth. But the curve did not follow the curve that would be expected with increasing distance -- it followed an angular dependence that indicated an instrument effect. 2b) This dependence on angle is the one that one would expect if there were some difference in sensitivity of the detectors to angle or location in the tank. Such as depth, or some other difference between top and bottom of the tank. The pressure of the fluid at the top of the SuperK is several times less than the pressure in the bottom of the tank. Which could have resulted in bubbles messing with the discrimination between electron and muon signatures. In short, my current view is that the SuperK 'neutrino oscillations' are observer or instrument artifacts. Before we get into explaining "all the data," I want you to identify the specific model that YOU claim explains it all. Per Bahcall (1997), "Theoretical physicists have fertile imaginations; they have provided us with a smorgasbord of explanations based upon new particle physics, including vacuum neutrino oscillations, resonant oscillations in matter (the MSW effect), resonant magnetic-moment transitions, sterile neutrinos, neutrino decay, and violation of the equivalence principel by neutrinos. Most of these explanations can account for the existing experimental data if either two or three neutrinos are involved in the new physics beyond the standard electroweak model. All thses pareticle physics explanations, and other that I have not listed, can account for the existing data from solar neutrino experiments without conflicting with established laws of physics or with other experimental constraints." "The number of proposed particle physics explanations exceeds the diagnostic power of the existing solar neutrino experiments. I think it is unlikely that the next generation of solar neutrinos experiments will be able to eliminate all but one possible particle physics explanation." I'll summarize my own explanation as simply that the central temperature of the Sun is just a bit lower than our current simulations predict -- due to the deposition of gravitational energy into the Sun amounting to about 1% of the measured output (which is not included in current simulations). The 'slightly lower temperature' solution was found sufficient to explain all differences in the past -- but no suitable mechanical explanation for the energy source (i.e. differential rotation of the Sun) could be found. The 'low' 8B (chlorine) measurements are thus explained (due to the very strong temperature dependence of the 8B reaction) -- simultaneously with with the minimal change in neutrinos from other chains. greywolf42 ubi dubium ibi libertas |
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Neutrino Oscillations
"g" == greywolf42 writes:
Bjoern "Neutrino oscillations are clear evidence for neutrino masses." g Neutrino 'oscillations' are postulated to explain a discrepancy g between theory and observation. This is more of a sociological comment than scientific, but I have noticed this phenomenon among others insistent that various standard models are wrong. There seems to be an insistence that a prevailing theory or model predict every possible observed effect *or* that it cannot possibly be used. (greywolf is fond of accusing scientists of ignoring the third option....) Take the Standard Model of particle physics. Originally it put the mass of the neutrino at 0 eV. Why? Well, it was certainly consistent with all observations, but I don't think it was predicted ab inito from the Model. After all, particle physicists still struggle to understand why the various particles have the masses that they do. So what happens when it turns out that the neutrinos do have mass? There's a well-developed mechanism for handling particle masses. Should one junk the entire Standard Model, simply because it didn't predict something, particularly given that it can't predict any particle masses? or do you adjust the Model slightly? Only very rarely do wholesale paradigm shifts (like quantum mechanics) occur. Most of the time, minor modifications in a theory or model are sufficient to allow it to accomodate new data. Is that bad science or a sign that we are learning something? Bjoern "O.k., then let's word it in another way: Do you have another Bjoern explanation, besides neutrino oscillations, for the experimental Bjoern facts that 1) Superkamiokande measured more atmospheric neutrinos Bjoern from above than from below, with a systematic dependence on zenith Bjoern angle, and 2) the total neutrino flux from the sun matches nicely Bjoern the predicted electron neutrino flux from the standard solar model? Bjoern There are some more experiments which show similar things, but Bjoern these are the best known." I'd add to the list the observations of neutrino oscillations from Earth-bound reactors. No solar model uncertainties added. -- Lt. Lazio, HTML police | e-mail: No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html |
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Neutrino Oscillations
Dear Joseph Lazio:
"Joseph Lazio" wrote in message ... .... Take the Standard Model of particle physics. Originally it put the mass of the neutrino at 0 eV. Why? Well, it was certainly consistent with all observations, but I don't think it was predicted ab inito from the Model. After all, particle physicists still struggle to understand why the various particles have the masses that they do. So what happens when it turns out that the neutrinos do have mass? How long after a SNe is seen does the neutrino "cloud" arrive? David A. Smith |
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Neutrino Oscillations
greywolf42 wrote:
This post is a followup to comments made by Bjoern Feuerbacher in another thread. The other thread was getting terribly long - and was on another subject (the book, The Big Bang Never Happened, and Ned Wright's webpage on same). Bjoern: "Neutrino oscillations are clear evidence for neutrino masses." greywolf42: Neutrino 'oscillations' are postulated to explain a discrepancy between theory and observation. Bjoern: When you say "theory", do you mean the standard solar model? No. I mean the theory of the operation of the SuperK and neutrinos that pass through the Earth. In other words, the theory of weak interactions? Or what do you mean exactly? If yes, then you are wrong - neutrino oscillations weren't postulated only because of the observations of solar neutrinos which contradicted this model. Good thing that I wasn't referring to the solar model. Well, then what do you think why neutrino oscillations were postulated? You seem to think they were postulated because of some discrepancies in the results of SuperKamiokande. If yes, then you are obviously wrong - they were postulated before SK even existed. And today, this discrepancy has disappeared: when measuring *all* neutrinos (the SNO measurements), it turns out that the result agrees well with the predictions of the solar model. That wouldn't explain the discrepancies that *existed* in other detectors. For example? AFAIK, all neutrino observations obtained in the last decade(s) agree today with the theoretical model we have today. And again, AFAIK, there weren't any discrepancies in detectors which couldn't have been explained by neutrino oscillations. IIRC, the detectors in which these so-called "discrepancies" were detected were even *built* in order to detect the oscillations, hence what was detected weren't really discrepancies, but the *signal* one was looking for! Do you have a counter example? Got a reference for 'the SNO measurements'? My detailed information was all design (1993, "Neutrino Astrophysics," Bahcall). Oh, that's absolutely outdated! There have been lots of new discoveries in neutrino physics in the last two or three years! (didn't you notice the Nobel prize last year?) The SNO results can be found e.g. in this article: Int. J. Mod. Phys. A, vol.17, no.24, 30 Sept. 2002 p.3378-92 But there are lots more relevant articles! Try doing a web search. In 1997, "Unsolved Problems in Astrophysics," Bahcall and Ostriker, ed, there are "three solar neutrino problems:" Also outdated. 1) Calculated versus observed chlorine rate, 2) Incompatibility of Chlorine and Water (Kamiokande) experiments, 3) Gallium experiments: No room for 7Be neutrinos. I don't know so much about this, but try looking at the reference I gave above. Bjoern: "Do you have another explanation for neutrino oscillations which fits all of the data?" greywolf42: "Neutrino oscillations ARE a theoretical explanation. Not data." Bjoern: "O.k., then let's word it in another way: Do you have another explanation, besides neutrino oscillations, for the experimental facts that 1) Superkamiokande measured more atmospheric neutrinos from above than from below, with a systematic dependence on zenith angle, and 2) the total neutrino flux from the sun matches nicely the predicted electron neutrino flux from the standard solar model? There are some more experiments which show similar things, but these are the best known." I think you somehow garbled #2. Read it again, and let me know if you really meant it just that way. Yes, I really meant it this way. Let's limit the discussion to the SuperK (#1), for now. Be advised that my understanding of the SuperK experiments on 'neutrino oscillation' comes solely from a Scientific American article, a couple of years back. *sigh* As I suspected: like everyone who doubts scientific results, you have read only pop science accounts and nevertheless think you are qualified to judge the validity of the experiments and the conclusions. I haven't stirred myself to more serious study of the experiment. But nevertheless, you think that neutrino oscillations don't exist? I'd appreciate hearing your personal favorite reference of same, so that we can work from the same pages. Discussions about neutrino oscillations can be found in most modern textbooks about particle physics. My favourite one "An Introduction to Quantum Field Theory" by Peskin and Schroeder; IIRC, they discuss neutrino oscillations. About the SK experiment itself, I don't know so much; I heard some technical talks about it, but I don't remember any actual reference, sorry. My primary recollections of the experimental problems in SuperK were as follows: 1) The discrimination between an electron Cerenkov ring and a muon Cerenkov right was totally subjective (qualitative, not quantitative). Narrow rings (those with a vertex originating near the detection wall) would be almost impossible to differentiate. The dependence of the result upon this discrimination was quite strong. Should this human discrimination be in error by as much as only 10% (which is easy to do) the 'effect' would have disappeared. I don't know about this, sorry. But bear in mind that this was already some years ago and probably the methods have improved so far! I remember, too, that when the first results of SK came up, they were met with lots of skepsis, but later, when they improved there measurements and more data came in, they were accepted. Also bear in mind that the results of SK agree with the results of other experiments. 2a) The dependence on zenith angle was assumed to mark a difference in distance travelled through the Earth. Well, isn't this a quite natural assumption??? But the curve did not follow the curve that would be expected with increasing distance -- it followed an angular dependence that indicated an instrument effect. That's new to me. I saw some diagrams with predicted theoretical curves (where the theoretical prediction was based on the traveled distance) and measured values, which agreed quite nicely within their errors bounds (I must mention that these weren't the preliminary results, but the later, improved ones, with more data included). Unfortunately, IIRC, I saw these diagrams in a talk and therefore don't have a reference available for them, sorry. 2b) This dependence on angle is the one that one would expect if there were some difference in sensitivity of the detectors to angle or location in the tank. Where should this dependence come from? And don't you think they have checked for this possibility? Such as depth, or some other difference between top and bottom of the tank. How should have this has an influence on the sensitivity of the detectors? The pressure of the fluid at the top of the SuperK is several times less than the pressure in the bottom of the tank. How should this affect a photomultiplier??? Which could have resulted in bubbles messing with the discrimination between electron and muon signatures. I don't know enough about the actual experimental methods, but I think that such bubbles would have been noticed! In short, my current view is that the SuperK 'neutrino oscillations' are observer or instrument artifacts. And all of the physicists who disagree with you on this and think the results are genuine were duped somehow? You, the layman, can judge this better than the physicists who were actually involved in the experiment? Sorry, doesn't sound credible to me. Before we get into explaining "all the data," I want you to identify the specific model that YOU claim explains it all. I think a comprehensive discussion can be found e.g. in Physics Letters B, vol.543, no.1-2, 5 Sept. 2002 p.38-40 Per Bahcall (1997), "Theoretical physicists have fertile imaginations; they have provided us with a smorgasbord of explanations based upon new particle physics, including vacuum neutrino oscillations, resonant oscillations in matter (the MSW effect), AFAIK, these first two are sufficient to explain the data. resonant magnetic-moment transitions, sterile neutrinos, The latter are still in discussion, but AFAIK not absolutely necessary to explain the data. neutrino decay, and violation of the equivalence principel by neutrinos. Most of these explanations can account for the existing experimental data if either two or three neutrinos are involved in the new physics beyond the standard electroweak model. All thses pareticle physics explanations, and other that I have not listed, can account for the existing data from solar neutrino experiments without conflicting with established laws of physics or with other experimental constraints." Well, that's right. "The number of proposed particle physics explanations exceeds the diagnostic power of the existing solar neutrino experiments. That's unfortunately still right, too. The possible explanations have been greatly reduced, but there are still uncertainties. I think it is unlikely that the next generation of solar neutrinos experiments will be able to eliminate all but one possible particle physics explanation." Right. I'll summarize my own explanation as simply that the central temperature of the Sun is just a bit lower than our current simulations predict Well, that doesn't explain that the *total* neutrino flux from the sun, measured by SNO, fits nicely with the theoretically predicted value for the number of electron neutrinos which are produced in the sun. -- due to the deposition of gravitational energy into the Sun amounting to about 1% of the measured output (which is not included in current simulations). What do you mean by "deposition of gravitational energy"? That the sun is shrinking and thereby gravitationally energy is converted into electromagnetic energy? I doubt that this isn't included in current simulations! The 'slightly lower temperature' solution was found sufficient to explain all differences in the past -- but no suitable mechanical explanation for the energy source (i.e. differential rotation of the Sun) could be found. The 'low' 8B (chlorine) measurements are thus explained (due to the very strong temperature dependence of the 8B reaction) -- simultaneously with with the minimal change in neutrinos from other chains. Well, it doesn't explain the new SNO results. Bye, Bjoern |
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Neutrino Oscillations
(formerly)" wrote:
Dear Joseph Lazio: "Joseph Lazio" wrote in message ... ... Take the Standard Model of particle physics. Originally it put the mass of the neutrino at 0 eV. Why? Well, it was certainly consistent with all observations, but I don't think it was predicted ab inito from the Model. After all, particle physicists still struggle to understand why the various particles have the masses that they do. So what happens when it turns out that the neutrinos do have mass? How long after a SNe is seen does the neutrino "cloud" arrive? IIRC, in the case of SN 1987A (AFAIK, the only case in which neutrinos from a SN were observed), the neutrinos arrived *before* the light from the SN. And no, this doesn't imply that neutrinos travel faster than light - only that they can penetrate the surrounding layers easier. Bye, Bjoern |
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Neutrino Oscillations
Joseph Lazio wrote in message ... "g" == greywolf42 writes: Bjoern "Neutrino oscillations are clear evidence for neutrino masses." g Neutrino 'oscillations' are postulated to explain a discrepancy g between theory and observation. This is more of a sociological comment than scientific, Theory and postulates are scientific. Not sociological. The sociological effect is the herd mentality among grant-chasing bureaucrats -- always pounding after the latest will-o-the-wisp, ad hoc phantom. but I have noticed this phenomenon among others insistent that various standard models are wrong. There seems to be an insistence that a prevailing theory or model predict every possible observed effect *or* that it cannot possibly be used. (greywolf is fond of accusing scientists of ignoring the third option....) That's the inverse of reality. It's the 'old guard' who always insist that any non-standard theory explain everything in the universe (including everything not yet explained by the 'standard' models) -- not those who question. Those who question the standard models ususally point only to one or two specific predictions of the 'standard' models that are contradicted by observation. Take the Standard Model of particle physics. Originally it put the mass of the neutrino at 0 eV. Why? The neutrino (and its zero mass) were postulated 40 years prior to the first theory with the name "Standard Model". Well, it was certainly consistent with all observations, but I don't think it was predicted ab inito from the Model. In which case, the Standard Model cannot be said to explain anything about the neutrino. After all, particle physicists still struggle to understand why the various particles have the masses that they do. Maybe after 30 years of wasting their time with a "model" that doesn't help them understand anything about the masses of particles, they should try other approaches. So what happens when it turns out that the neutrinos do have mass? Nothing, of course. Neutrinos are what neutrinos are. Nothing happens to them when we change our minds. There's a well-developed mechanism for handling particle masses. Not in the Standard Model -- according to your prior statement. Should one junk the entire Standard Model, simply because it didn't predict something, particularly given that it can't predict any particle masses? If a model has no predictive power, then is it unscientific. For it cannot be disproved. So, yes, a "model" that can't predict such should be scrapped. or do you adjust the Model slightly? Only very rarely do wholesale paradigm shifts (like quantum mechanics) occur. The Standard Model is not a paradigm. Junking it would not be a paradigm shift. Most of the time, minor modifications in a theory or model are sufficient to allow it to accomodate new data. Is that bad science or a sign that we are learning something? Repeat all of the above argument of yours, but replace "Standard Model" with "Ptolemaic system." Your argument is unchanged. Why *should* those folks have junked their model? All they ever had to do was make occasional, minor modifications every time they got a new observation. Why the 'invisible' snipping Lt. Lazio? {replacing the portions that relate to Lazio's later comments on 'solar.'} ========================================== Bjoern: When you say "theory", do you mean the standard solar model? No. I mean the theory of the operation of the SuperK and neutrinos that pass through the Earth. If yes, then you are wrong - neutrino oscillations weren't postulated only because of the observations of solar neutrinos which contradicted this model. Good thing that I wasn't referring to the solar model. Bjoern: "Do you have another explanation for neutrino oscillations which fits all of the data?" greywolf42: "Neutrino oscillations ARE a theoretical explanation. Not data." ========================================== Bjoern "O.k., then let's word it in another way: Do you have another Bjoern explanation, besides neutrino oscillations, for the experimental Bjoern facts that 1) Superkamiokande measured more atmospheric neutrinos Bjoern from above than from below, with a systematic dependence on zenith Bjoern angle, and 2) the total neutrino flux from the sun matches nicely Bjoern the predicted electron neutrino flux from the standard solar model? Bjoern There are some more experiments which show similar things, but Bjoern these are the best known." I'd add to the list the observations of neutrino oscillations from Earth-bound reactors. No solar model uncertainties added. There's no 'list' to add to. I said I wasn't referring to Solar measurements. And perhaps you'd care to provide your personal favorite experiment citation on the reactor experiment. {Lazio makes another 'invisible' snip. Apparently because he doens't want to stick his neck out.} {I'll replace just the request for a statement of position.} ================ Before we get into explaining "all the data," I want you to identify the specific model that YOU claim explains it all. Per Bahcall (1997), "Theoretical physicists have fertile imaginations; they have provided us with a smorgasbord of explanations based upon new particle physics, including vacuum neutrino oscillations, resonant oscillations in matter (the MSW effect), resonant magnetic-moment transitions, sterile neutrinos, neutrino decay, and violation of the equivalence principel by neutrinos. Most of these explanations can account for the existing experimental data if either two or three neutrinos are involved in the new physics beyond the standard electroweak model. All thses pareticle physics explanations, and other that I have not listed, can account for the existing data from solar neutrino experiments without conflicting with established laws of physics or with other experimental constraints." "The number of proposed particle physics explanations exceeds the diagnostic power of the existing solar neutrino experiments. I think it is unlikely that the next generation of solar neutrinos experiments will be able to eliminate all but one possible particle physics explanation." ================ greywolf42 ubi dubium ibi libertas |
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Neutrino Oscillations
"g" == greywolf42 writes:
g Joseph Lazio wrote in message g ... Most of the time, minor modifications in a theory or model are sufficient to allow it to accomodate new data. Is that bad science or a sign that we are learning something? g Repeat all of the above argument of yours, but replace "Standard g Model" with "Ptolemaic system." Your argument is unchanged. Why g *should* those folks have junked their model? All they ever had to g do was make occasional, minor modifications every time they got a g new observation. Ah, but that's the point. That's exactly what happened, for centuries. Until somebody came up with extremely high precision data (Tycho) and a new way of looking at things (Kepler). Is this a bad thing? Well, as you pointed out, epicycles did explain the available data, and what's the purpose of a scientific model but to explain the available data? (Of course the monks and others who developed and maintained the Ptolemaic system were not conducting science in the way we understand the term today, but their actions were equivalent to what I describe.) Only when extraordinary evidence was accumulated, did the extraordinary explanation finally come to be accepted. Moreover, the other point that you don't seem to understand (and it's the reason I continue to use "model" rather than "theory") is that one has to be very clear about what the Standard Model of particle physics and the Big Bang model predict. The Big Bang model predicts that the Universe was hotter and denser in the past, regardless of whether the Hubble constant is 50 km/s/Mpc, 75 km/s/Mpc, 100 km/s/Mpc, or 500 km/s/Mpc. The Standard Model of particle physics predicts particle interactions, regardless of whether the electron mass is 0 eV, 250 keV, 511 keV, or 2000 keV (I think). The task of experiments is to measure or constrain these model parameters (and the hope is that someday a theory will be developed that allows one to predict what these various model parameters are). g Why the 'invisible' snipping Lt. Lazio? Because I recognize that not everybody reads Usenet over high-speed links. Thus, I try to snip points that I find redundant, that I believe I address elsewhere, or that I find too silly to bother wasting my time addressing. "Neutrino oscillations ARE a theoretical explanation. Not data." Bjoern "O.k., then let's word it in another way: Do you have another Bjoern explanation, besides neutrino oscillations, for the Bjoern experimental facts that 1) Superkamiokande measured more Bjoern atmospheric neutrinos from above than from below, with a Bjoern systematic dependence on zenith angle, and 2) the total Bjoern neutrino flux from the sun matches nicely the predicted Bjoern electron neutrino flux from the standard solar model? Bjoern There are some more experiments which show similar things, but Bjoern these are the best known." I'd add to the list the observations of neutrino oscillations from Earth-bound reactors. No solar model uncertainties added. g There's no 'list' to add to. I said I wasn't referring to Solar g measurements. I see that you haven't addressed the question that Bjoern asked, though, what's your explanation for the data? g And perhaps you'd care to provide your personal favorite experiment g citation on the reactor experiment. I'm not sure I have a favorite, and, in any event, search engines do exist. -- Lt. Lazio, HTML police | e-mail: No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html |
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Neutrino Oscillations
Bjoern Feuerbacher wrote in message ...
That's new to me. I saw some diagrams with predicted theoretical curves (where the theoretical prediction was based on the traveled distance) and measured values, which agreed quite nicely within their errors bounds (I must mention that these weren't the preliminary results, but the later, improved ones, with more data included). Unfortunately, IIRC, I saw these diagrams in a talk and therefore don't have a reference available for them, sorry. At the recent International Cosmic Ray Conference in Tsukuba, Japan, Masatoshi Koshiba (the guy who got the nobel prize for the Kamioka NDE stuff) himself gave a lecture about "The birth of Neutrino Astrophysics". The PDF of his slides can be found he http://www-rccn.icrr.u-tokyo.ac.jp/i...3/program.html At the very top of the "plenary" sessions. Some of the "usual" graphs are in there. For much more detail, you could look at Yoichiro Suzuki's talk on "Neutrino Oscillations" but I don't think the slides will be terribly useful to the layperson without verbal explanations. greymatter42 wrote: In short, my current view is that the SuperK 'neutrino oscillations' are observer or instrument artifacts. I don't mind that you are ignorant: Ignorance is merely the natural state of the uninformed. I don't even mind that you are *intentionally* ignorant: all the information of the world is accessible to you and all you have to do is bother to look. But there's no law against lazyness and you're free to remain ignorant to the end of your life. But making *judgements* about something from a position of ignorance is stupid. And making such judgements in contradiction of a large number of people who have actually spent years of their lives expending a LOT of effort on removing themselves from the state of ignorance is at the very least an insult to those people. resonant magnetic-moment transitions, sterile neutrinos, The latter are still in discussion, but AFAIK not absolutely necessary to explain the data. Sterile neutrinos have been excluded by several experiments for a couple of years now -- they went down before SMA solutions. |
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Dear Bjoern Feuerbacher:
"Bjoern Feuerbacher" wrote in message ... (formerly)" wrote: Dear Joseph Lazio: "Joseph Lazio" wrote in message ... ... Take the Standard Model of particle physics. Originally it put the mass of the neutrino at 0 eV. Why? Well, it was certainly consistent with all observations, but I don't think it was predicted ab inito from the Model. After all, particle physicists still struggle to understand why the various particles have the masses that they do. So what happens when it turns out that the neutrinos do have mass? How long after a SNe is seen does the neutrino "cloud" arrive? IIRC, in the case of SN 1987A (AFAIK, the only case in which neutrinos from a SN were observed), the neutrinos arrived *before* the light from the SN. And no, this doesn't imply that neutrinos travel faster than light - only that they can penetrate the surrounding layers easier. I was not supposing they were superlumenal. I was asking to lead to the question, if they have finite mass, how can they propagate at c? David A. Smith |
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Neutrino Oscillations
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