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The interesting part of the search is over -- what follows is a couple of decades of shrinking the error bars. As it stands right now, all the data is converging to a bog-stock standard model particle. There is an anomaly in some of the ATLAS data, but the discrepancy is shrinking. According to the LHC data presented at the Moriond Conference on March 6, the anomaly isn't getting worse when more data is included, which means that it probably can be explained by something other than new physics. Add in the 2.5GeV difference between the Higgs masses in the ATLAS data, and it looks more like there is some kind of systemic error with ATLAS, not a glimpse of new physics. All other data are tightly consistent with the SM. And for what it is worth, the idea that a spin determination needs to be made is a bit of wishful thinking. It's probably Director Bertolucci trying to keep the media interest going. A 126 GeV particle can have only spin zero -- there isn't even a model for a spin 2 resonance that is simultaneously mathematically rigorous and not eliminated by experimental evidence that already exists. According to this excellent blog by a particle physicist based in Paris, the best chance of finding new physics is observing the Higgs making non-SM interactions in some hitherto unexpected decay channel, something that is possible, but very, very unlikely. Given the fierce competition for shrinking scientific research funding, getting funding for that kind of research is not going to happen, and the grumbling coming from particle physicists is because they realize that the Higgs is not going to be a meal ticket for them anymore. .

I'm the guy who write the software for the reactor (and the accelerator) of TFA. And yes, it run Linux, on embedded Xilinx cards with custom FPGAs. I can't vouch for the ability of the system to transmute long-life waste in a semi-industrial way as it's only a research reactor, not even a demonstrator. But it's the 3rd prototype of its kind and it's working well enough. More information is available here in french, and, as a long time /. member, if you have questions about the control/command software, I'll be happy to answer when I wake up in the morning ! Yeah, the name of the experiment is somewhat confusing: Genepi/Guinevere/3C/Venus/Ganddalf. One is the accelerator, one is the reactor, one is the data acquisition, one is the combined experiment... I get lost too.

Someone has invented a neutrino telescope:- http://icecube.wisc.edu/ http://antares.in2p3.fr/ But the angular resolution is awful and the energy threshold is very high. So this only detects neutrinos from really super powerful cosmic stuff like black holes colliding.

Eh, you're being a little quick to dismiss things. A third author typically had, at the very least, some meaningful role in the research that was done, and is a full member of whatever collaboration did it. (And probably has a Ph.D., or is working on one.)

I'm an associate member of a collaboration, and as such I make it onto the authors list for various little announcements they put out, but although I take a lot of the data, I'm not as involved in analyzing what it all means (I'm still shy of a M.Sc) so I usually just wind up in the "thanks to..." part at the end of real papers. :)

Don't ever try to discuss Labview licenses with National Instruments

Yeah, I'm pissed off too. We had a site license where they sent us a set of CDs and we could install them wherever we wanted, no strings attached, just type in the license number.

But then the powers-that-be thought they could save money by getting a floating license. So now all the acquisition and development systems need a flexlm or similar piece of shit DRM that connects to a license server 200km away that connects to who-the-fuck-knows in Austin, Tx.

Guess what, I design acquisition systems that go in Antarctica or experimental nuclear reactors. Hint: they are OFF the net, you asswipes.

The three physical (mass eigenstate) neutrinos [nu_1, nu_2, nu_3] are mixtures of the three interaction states [nu_e, nu_mu, n_tau] and are related by a rotation matrix R called the MNS matrix. It's just a matrix rotation.

Today we do believe we understand the "solar neutrino problem" in terms of mixing of the three states. For the solar neutrinos, in fact mixing due to matter is dominant (rather than mixing due to the masses). There are numerous neutrino experiments going on today, but so far they have only been sensitive to the two mass differences (which are now pinned down quite precisely). We still don't know the absolute mass scale. Several experiments have set upper limits however. They are all in the 1 eV range and come from cosmology, or direct searches in tritium beta decay. The next major experiment to determine the absolute value of the mass is KATRIN. Some other upcoming experiments are Double CHOOZ, Daya Bay, T2K (Tokai to Kamioka), and in the US, MINOS.

There are anomalies in the existing data, however. I don't think finding the mass will be the last word on this subject.

A more lightweight solution that also uses multiple parallel FTP streams and doesn't require the whole GridFTP setup is bbftp http://doc.in2p3.fr/bbftp/. Incidentally, it also uses either SSL for encryption or ssh as a transport; might be interesting to see how multithreaded-ssh + bbftp performs.

Tangentially, at my lab we recently evaluated an anti-P2P "solution" that initially experienced some interesting crashing problems exposed by bbftp. If we get permission, there may be an interesting paper coming out of that evaluation.

I'll take you on that. We are preparing to hire someone for a year in a nuclear research facility in an IT job. Position not fully defined yet (either sysadmin or embedded). In Grenoble. C;-)

* Neutrino
* History of the neutrinos [from our perspective, mind you]
* The Ultimate Neutrino Page
etc. I should go call up my particle physicist body to post up some comments. :)

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Neutrinos can be detected.

I read it. The fact remains that graphite can burn.

The South African Pebble Bed Modular Reactor (PBMR) is a form of reator known as High-Temperature Gas-cooled Reactor (HTGR).

These differ from the Windscale reactor (UK) and Cherynobl reactor (Russia/Ukraine) in that the causes of the failures of these systems are eliminated by design.

" The estimated probablilty of significant radiation release has been estimated [to be] three orders of maginitude less than for PWR reactors. " This is good.

However:

" The main safety concern for HTGR is that intrusion of air in the vessel would lead to combustion of the graphite. "

We calls that fire caused by accident, and is directly related to the flammability of graphite, which is precisely what I mentioned in my first post.

Source of quotes:
Hybrid Nuclear Reactors; Institut des Sciences Nucleaires; Grenoble, France

To show that neutrinos have mass, it suffices to observe solar neutrinos and look for changes in neutrino flavour. Last I heard, although large regions in which the neutrino masses could have lain had been ruled out, the evidence was mounting in favour of flavour changes and neutrinos having mass.

However, with all I've heard about neutrino studies over the last few years in a Nuclear Physics department, this article doesn't give enough information to let me work out if I already know of the experiment or not (though I probably have attended seminars by associated researchers; these projects are not exactly three-person exercises capable of being missed!) They don't even give the experiment's *name* - NOMAD, CHORUS, SNO, etc (many listed on this page)

The article *might* be referring to the UK Dark Matter Collaboration who apparently look for neutralinos instead (neutralinos appear to crop up deep inside what we Nuclear Physicists call 'Particle Physics', which is full of leptons and mesons and other fun particles, fine, and some of the most brain-bending mathematics it has been my priviledge to not understand.)

Rachel

There's been a lot of research going on about neutrinos in the recent years. I still recall the big recent newsbreak when they discovered that they can spontaneously change to another form. The Ultimate Neutrino Page and Neutrino History have some good news.

The thing I've been thinking is... what they really need is another somewhat-close supernova to occur. That should give scientists even more data to digest.

to arrive... they're the best thing for preventing those nasty athlon core meltdowns.

Hi,

Neutrinos interact with matter only through the weak nuclear force (and probably the gravitational force; whether they have mass or not is still kind of open, although it seems increasingly more likely that they have a non-zero mass). You are correct that the neutrino reaction does not directly produce a gamma ray photon.

The collision of a neutrino with a chlorine atom changes one of the chlorine atom's neutrons into a proton (note: a weak nuclear reaction), thus transforming the Chlorine atom to an Argon atom (atomic numbers 17 and 18, respectively). The reaction also produces an electron (charge must be conserved).

The particular isotope of argon produced (Ar-37) is unstable to radioactive decay. In a few days it spontaneously reverts back to Chlorine-37, producing an anti-electron in the process:

Ar(37) -> Cl(37) + neutrino + e(+)

The anti-electron immediately finds its way to the nearest electron, and they annihilate, producing a pair of gamma rays, which lead to a cascade of optical photons, which are detected by the experiment.

Whew.

Note that Super-K (the Japanese experiment that was damaged recently) doesn't actually use this chlorine setup, it uses something similar using ultra-pure water as the reactant. Also, I believe the water-based detectors rely on the kinetic energy of the electron in the first reaction to produce cerenkov radiation, rather than a subsequent beta decay/annihilation of anti-electron.

Here are some links on neutrino detector experiments. Google has all these and more.

The Solar Neutrino Problem

Review of all experiments

Sudbury Neutrino Observatory uses deuterium (a/k/a heavy water)

Super-Kamiokande

AMANDA uses Antarctic Ice as the reactant.

I recommend the first link for a detailed overview of solar neutrinos.

enjoy,
Jason

Just to stay in the subject, and for those who might be interested, check out this detector.

It's sort of like the water version of the ice-cube detector.

Much nicer site for a vacation, too. 8^)

The home page is here.

Just to stay in the subject, and for those who might be interested, check out this detector.

It's sort of like the water version of the ice-cube detector.

Much nicer site for a vacation, too. 8^)

The home page is here.

I would've thought there would be nothing but solid chunks of ice by the South Pole.

No, There is land below the ice at the SP. You are thinking of the North Pole, which doesn't have land below the ice.

There is an inaccurate statement in the article that has mislead you:

Neutrinos travel through Earth all the time without being detected.

This should read: Most Neutrinos travel through Earth all the time without being detected.

There is a nice introduction into the discovery of the neutrino at
http://wwwlapp.in2p3.fr/neutrinos/aneut.html

So the neutrino was the last of the leptons and quarks for which there was not experimental evidence. Now what?

Good history (although the translation from French is kind of amusing) here

and this background info is a little better (also, there is more yellow on the page :)
http://www.ps.uci.edu/~superk/neutrino.html

Minor correction: Astronomy Picture of the Day for February 25th was the SNO Detector, not the 26th as indicated by the word "yesterday", which should have been edited.

This picture shows the SNO Detector facility, which is an immense step into exploring the more theoretical sciences and their validity/effects on the universe. Applications for manipulation and detection of such particles in the foreseeable future could be data transfer or wireless communication through unlimited barriers, along with many other possibilities. This is a somewhat concrete and unexpected implementation of neutrino detectors today and in the next century, but who knows what's to come?

Interestingly enough, much data on neutrinos (as evidenced by the NEMO website) is not for public viewing. Why is this?

treker

__Off-Topic Below__
Stephen Baxter's Xeelee sequence books (Flux, Timelike Infinity, Ring) seemed very engaging to me--and even somewhat relevant to this topic!

Incidentally, someone was mentioning the bizarre French laws on encryption. These laws have been repealed a year or so ago: by that same (socialist) government which is now proposing this bill.

More precisely, the (socialist) government issued regulations (decrees 99-199 and 99-200) superseding the former regulations. Most notably, these new regulations say that people can use freely 128-bit encryption as long as the software has been declared. The user does not need to declare the software; it is sufficient that somebody has declared the availability of the software to the authorities. For instance, IN2P3 (a national research center on particle physics) modified SSH and made SSF (limiting the lenght of the private key to 128 bits) and declared it. Now just anybody can download it (source code available) and use it fully legally without further hassle.

A key length of 128-bit is supposed to be sure against attacks by corporations and governments for a certain number of years. The French government was nevertheless forced to set a limit since simply removing any limit would have been... illegal. The decree setting limits is actually a supplement to a law voted by parliament; this law stipulated that a limit should be set by the executive branch. The executive branch could not legally put no limit on keylength, since this would void the law of its substance; such a decree would be open to litigation and likely to be cancelled by the judiciary.

The government said at the time that they were going to propose a law (to be voted by parliament) removing the last restrictions. However, this has not taken place; reasons may be the relative lack of interest of the public in the matter and the general overload of Parliament (greatly made worse, I must say, by the silly campaign from the right wing against the domestic partnership law).

I suggest that we lobby a bit on this issue.

Note: in France, the socialist party is more or less like the US democratic party (a bit further to the left). They have little to do with the so-called "socialist republics".

Incidentally, someone was mentioning the bizarre French laws on encryption. These laws have been repealed a year or so ago: by that same (socialist) government which is now proposing this bill.

More precisely, the (socialist) government issued regulations (decrees 99-199 and 99-200) superseding the former regulations. Most notably, these new regulations say that people can use freely 128-bit encryption as long as the software has been declared. The user does not need to declare the software; it is sufficient that somebody has declared the availability of the software to the authorities. For instance, IN2P3 (a national research center on particle physics) modified SSH and made SSF (limiting the lenght of the private key to 128 bits) and declared it. Now just anybody can download it (source code available) and use it fully legally without further hassle.

A key length of 128-bit is supposed to be sure against attacks by corporations and governments for a certain number of years. The French government was nevertheless forced to set a limit since simply removing any limit would have been... illegal. The decree setting limits is actually a supplement to a law voted by parliament; this law stipulated that a limit should be set by the executive branch. The executive branch could not legally put no limit on keylength, since this would void the law of its substance; such a decree would be open to litigation and likely to be cancelled by the judiciary.

The government said at the time that they were going to propose a law (to be voted by parliament) removing the last restrictions. However, this has not taken place; reasons may be the relative lack of interest of the public in the matter and the general overload of Parliament (greatly made worse, I must say, by the silly campaign from the right wing against the domestic partnership law).

I suggest that we lobby a bit on this issue.

Note: in France, the socialist party is more or less like the US democratic party (a bit further to the left). They have little to do with the so-called "socialist republics".

We recently had ssh installed on some of our (brittle) boxes, but the version "agreed on" in France is somehow called "ssf". Quoth I: "huh?" So I did a little searching and found the following page. It's in French, but the upshot is that the keyspace is limited to 2^40 (and of course it is illegal to modify it). Curiously, most French people I talk to have no idea that strong encryption is illegal. I don't know the status of the 128-bit thing; is it allowed for anyone in France?