Experiments Create Particles Out of a Vacuum Using Neutrinos 86
BarbaraHudson writes: In a new series of experiments, scientists report (abstract) that neutrinos, notable for how infrequently they interact with matter, can strike a glancing blow on an atom's nucleus, and the side effect is the generation of a new particle out of a vacuum. Professor Kevin McFarland says the creation of the new particle is what shields the nucleus from being blown apart by the collision. "Producing an entirely new particle – in this case a charged pion – requires much more energy than it would take to blast the nucleus apart – which is why the physicists are always surprised that the reaction happens as often as it does. McFarland adds that even painstakingly detailed theoretical calculations for this reaction 'have been all over the map.'"
Vetting the results (Score:2)
Toto's on his way to be tutored. They caught him playing with unleashed atoms, now they have to figure out who's going to take all the little pions.
New ways to generate... gravity? (Score:2)
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A quick look at wiki shows that gravitons are still unproven.
Pions are appareantly mesons (they have a quark and an antiquark) and decay to muons or gamma rays.
I'm not sure if there's any proposed relationship between pions and gravitons, though for that matter I'm not quite sure what a pion or a graviton is.
I will say that conversion of enery to matter and vice-veresa, in and of itself, seems to be old news.
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Also... (Score:2)
Pretty sure the title of TFS should have been:
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Gravitons are a force-mediating particle - if they exist. Completely different from pions. They are also near-impossible to observe directly - they make neutrinos look solid. There's no experimental confirmation they even exist, but certain theories far beyond my understanding predict them.
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IANATP either but, if gravity is nothing but bent spacetime, then gravitons are not needed. I, jumping up and down on earth, am following a straight path through space.
IAAP, although not a specialist in gravitons. However, I can tell you that they are hypothetical bosons that are introduced in theories that attempt to link gravity with quantum mechanics (or quantum chromo-dynamics if you prefer.) They mitigate the gravitational force in a quantum setting in much the same way as photons do for electromagnetism, gluons do for the strong force, and W+, W- and Z bosons do for the weak force.
You can find more information on them here. [wikipedia.org]
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"Is this a way to generate... gravity?"
It doesn't matter. It literally makes stuff out of 'thin air', that's the cool part.
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No, it makes stuff out of energy - nothing new to see there. Happens in particle accelerators all the time - throw enough energy around and the distinction between mass and energy gets blurry.
The cool part is that it's making something out of the impact energy instead of the atom being blown apart. That's something that wasn't expected, and it sounds like they have yet to figure out how/why it happens according to the theory - suggesting that we're on the verge of discovering some new physics, or at least
Re:New ways to generate... gravity? (Score:5, Informative)
pions are basically made up of quarks just like the neutron and the proton: there's nothing magical about it, and has absolutely nothing to do with gravitons (if such even exist except as a mathematical concept). the difference is that pions only contain two quarks (rather than three) and so they're not stable. imagine throwing two magnets into the air very very carefully and having them spin around each other for a very brief period of time. if they fly apart, splat no more particle: if they touch, splat no more particle. but for that incredibly short duration where the two quarks successfully spin around each other in close orbit, there you have a "pion".
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This isn't really related to gravity. Neutrinos are (as far as we know) fundamental particles. They are creating pairs of quarks (as far as we know fundamental) bound together to for a pion.
Gravitons are a different fundamental particle and interact much more weekly than do neutrinos. In principal there is probably some cross section for neutrinos interacting to produce gravitons, but the probability is exceptionally tiny.
Gravitons are part of the quantum description of gravity, but they have not been dire
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It's also worth mentioning that discovering the existence of gravitons would blow a hole in General Relativity - it's one of the areas where quantum mechanics and relativity stand in stark opposition. So unlike the Higgs Boson, gravitons aren't something where the theory all agrees that it should exist, but we just haven't (hadn't) actually spotted it yet.
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"Graviton" is just a working name for the virtual 'particles' (really mathematical points) that you move through equations and computer models. They have nothing to do with the actual mechanical reality of gravity, which we still have no clue about.
get Particles out of a vacuum (Score:3, Funny)
Its probably best to read the instructions
Its better with to ones that have a bag. Those ones with just a cylindrical plastic container that you just tip into the garbage can - even if you don't spill it, some of the smaller particles are going to get back into the air that you breathe.
Re: get Particles out of a vacuum (Score:2)
You don't breathe when you go outside? I guess that explains the basement dwelling tendencies.
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The Universe is just a simulation. The pion was an attempt to throw more "CPU" cycles at the problem. Now where did that energy come from? And, when will the double-A batteries that run it set to expire?
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Re:Getting something from nothing? (Score:4, Informative)
Where did you get the idea that vaccum is nothing? Actually, vacuum is a very busy place [wikipedia.org]
Re:Getting something from nothing? (Score:4, Interesting)
Rendering artifacts due to floating point precision!
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That would explain the uncertainty principle. A little aliasing noise to mask the quantization artifacts.
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...and that reply was meant for the GP
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That "nothing" is really something. Vacuum quantum fluctuations are physically real, cfr the Casimir effect.
So yeah, if the energy is right you can create particles out of the vacuum.
Re: Getting something from nothing? (Score:2)
There's no "nothing" anywhere in the universe. The only nothingness could be said to have preceded the universe.
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And that only if the universe is finite. If the universe is infinite (and the evidence suggests that it might well be) then it was probably *always* infinite, and the "big bang" was something that happened within it.
In fact one theory of the nature of the "big bang" is that the original universe was a completely empty false vacuum (i.e. the vacuum energy was stable but at a non-minimum energy) and eventually one point in the vacuum decayed to a lower energy state, spawning normal mass-energy in the process
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So the neutrino (i.e. something other than vacuum) hit another particle (also something other than vacuum), which grabbed some nearby nothingness to create a third particle? Sorry, but to me, the first two parts of it mean you're not creating stuff out of vacuum.
Peons (Score:2)
It's just like work: a bunch of pions popping in and out of a corporate vacuum.
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Isn't this how upper level managers are created? A corporate officer has vacuum for a brain and sees something whizzy on his computer screen. The whizzy thing is a neutrino, normally it is innocuous and rarely interacts with anything. However, in special circumstance the corporate officer accepts the neutrino and a new upper level manager is born.
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Dilbertian Physics, the next frontier.
Non-paywalled version (Score:5, Informative)
As usual for physics articles, a non-paywalled version is available on arXiv [arxiv.org], and has been so for more than a month before it appeared behind the paywall. Why do people who submit physics stories to slashdot aloways link to the useless paywalled version?
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Linking to the published Journal does have it's benefits. Rather than just being some random PDF we at least know that this appeared in some kind of useful publication and wasn't just made up and posted.
Now before someone says something about Journals accepting fake articles etc. Yes there are exceptions, but that's all, just exceptions. For the most part journals are good arbiters of solid science.
Re:Non-paywalled version (Score:5, Informative)
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You linked to two articles. The first one is "Reanalysis of bubble chamber measurements of muon-neutrino induced single pion production", which was paywalled. The second one is "Researchers show neutrinos can deliver not only full-on hits but also ‘glancing blows’", which isn't paywalled, and which further links to the arXiv article "Measurement of Coherent Production of $^\pm$ in Neutrino and Anti-Neutrino Beams on Carbon from $E_$ of $1.5$ to $20$ GeV". I was in a bit of a hurry and didn't rea
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So, basically, you clicked on the links to check if they were paywalled, in readiness to post an article about your personal bug-bear: paywalled articles.
Mostly, but with two differences. My personal bug-bear is not just paywalled articles. It is linking to paywalled articles when the same article is available in a non-paywalled form also. If you look closely, the article I linked to was not about paywalled articles. It was a link to the non-paywalled version of the first article mentioned in the summary. So I had two motivations: 1: To complain about unnecessary paywalling, and 2: To help people actually get at the paywalled article.
You omitted the relevant arXiv article (Score:2, Interesting)
TFS's topic of "Experiments Create Particles Out of a Vacuum Using Neutrinos" is not discussed in the paper
of 18 Nov which you linked, but in McFarland's 25 Nov paper
From the latter,
Re:Non-paywalled version (Score:4, Funny)
If you keep that shit up, people will start skipping the articles entirely.
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Well, enough glancing blows and you can at least generate hamburger where there used to be elected officials, and that might be an improvement. But the particle accelerator would need to be quite small so that you could swing it effectively.
The link in summary goes to the wrong paper (Score:1)
The link in the summary goes to the wrong paper.
This is the link to the right pre-print paper: http://arxiv.org/abs/1409.3835
Horrible Summary (Score:5, Insightful)
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(sigh) You're doing it wrong - that link you gave is the wrong one . The article the summary links to has a link to the correct (and non-paywalled) article at arXiv.org. Have a nice day :-)
The link the GP gave is to the paper linked directly to by the summary (the direct link to the abstract), so some confusion is understandable. In the future, maybe make submissions discuss one and only one paper (or make it obvious they're two papers)?
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There are no new experiments, only new analysis of old experiments.
Whew, I heard gunfire last night and at first thought some thug physicist was firing neutrinos down the street. "What if one strikes a nucleus and releases a positron?" I wondered. That's weak!
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Actually, to be on the safe side, while you don't understand what you're doing, could you please do it in Alpha Centauri?
If you find a way to block high energy neutrinos from space reaching Earth, then moving equipment to Alpha Centauri should be easy by comparison...
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Tea, (Score:4, Funny)
Earl Grey, hot.
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Are you sure this isn't Darjeeling? :)
Solar neutrino panels (Score:2)