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CERN experiments to test the free-fall of antiatoms

https://cerncourier.com/does-a...

From http://cerncourier.com/cws/art...

The current candidates for the tape drives that will record LHC experimental data are the enterprise-class drives from IBM and Sun StorageTek. These are the IBM 3592 EO5, which has a native data rate of 100 MB/s; and the Sun StorageTek T10000, which has a native data rate of 120 MB/s. Both of these drives use a 500 GB capacity cartridge.

The interesting thing is that the LHC can generate up to 6GB of data per second, which means that even a 500GB tape will only last for 83 seconds. It's good that they've got all of those robots handling these tapes.

The T1000D drives can write at 250 MB/s (2 Gb/s) and have an uncompressed capacity of 8.5 TB. The article you site is for 2006, so things have changed in the intervening (e.g., it's no longer "Sun StorageTek" but "Oracle StorageTek" now).

From http://cerncourier.com/cws/art...

The current candidates for the tape drives that will record LHC experimental data are the enterprise-class drives from IBM and Sun StorageTek. These are the IBM 3592 EO5, which has a native data rate of 100 MB/s; and the Sun StorageTek T10000, which has a native data rate of 120 MB/s. Both of these drives use a 500 GB capacity cartridge.

The interesting thing is that the LHC can generate up to 6GB of data per second, which means that even a 500GB tape will only last for 83 seconds. It's good that they've got all of those robots handling these tapes.

There are no age-old libraries when you program on cutting edge megaflop and petaflop-scale supercomputers (Bluegene/P, Bluegene/Q, QCDOC) for high performance physics applications such as lattice QCD. Also the data analysis tools we use often require fits to ~20 parameter non-linear functions which would be virtually impossible to get right in Java syntax. For example check out some of the NNLO PQChPT fit forms on Bijnen's page.

Besides, I think everyone reading /. on any semi-regular basis already knows about the whole "capturing anti-matter" thing, so no need to repeat stuff like you're the only one who keeps up on the news.

You're assuming everyone has kept up on this news. It might be new to somebody, in which case this is incredibly helpful.

As much as I enjoy hangin' out with y'all here on /., I very much doubt that anti-matter specialists come here for the latest news on their specialty. Cern Courier, Physics Today, and Symmetry Magazine are fun reading, though perhaps some real physicists (I'm not one) can suggest better.

At http://cerncourier.com/cws/article/cern/30577 you can read a slightly sarcastic piece about what it would take to hold the quantities that Dan Brown used in his books.

Nice wry write-up - I like the details..

Well, IAAFPP (I Am A Former Particle Physicist, now no longer active in the field), and you have to be careful what you mean by "neutrino". In the Standard Model, neutrinos are partners to the charged leptons: electron, muon, or tau lepton. By "partner to", I mean connected (in a sense) by the weak force, which is the only non-gravitational force that acts on them (being neutral, they are immune to the electromagnetic force, and being leptons, they don't feel the strong force). Neutrinos are also very light, having near-zero mass.

This is what the Standard Model calls a neutrino. And there are, in fact, only 3 kinds. This was shown pretty convincingly by LEP at CERN. And it's also enough to discredit Heim's Theory (which no one really took seriously in the first place).

What this story is suggesting is that there may be a different kind of neutrino -- a so-called "sterile neutrino" -- that doesn't even feel the weak force. This isn't part of the Standard Model, but it is possible in certain extensions of the SM. This kind of neutrino doesn't act the same way as the SM neutrinos; it's a different beast, and comes about through a different part of the mathematics.

Why does the NYTimes article say things that are out of date, inaccurate and in some cases flat out wrong ? The interview with Myers is dated 2 July but this article from CERN itself dates from the 15th and does not specify any figures for the number of bad connections. They have to run the tests before they know how many bad connections there are, and that hasn't been completed.

So basically this is a fluff piece that takes various peoples statements out of context and tries to promote a problem that CERN itself does not support. Yes it's late, yes there are issues, but the title LHC struggles is hardly warranted.

Fortran has tons of libraries specialized to whatever scientific field you are working in, and is unavoidable in high energy physics especially.

Hopefully not forever, since CERN standardized on C++ for the Large Hadron Collider in the 1990s, although they have enormous amounts of legacy FORTRAN code.

Personally, I think FORTRAN should be taken out and shot. Godawful unmaintainable code is the norm , and there is nothing you can do in FORTRAN that you can't do in a cleaner environment like C++. People only still use FORTRAN because they are used to it, and it will not go away until all the old fucks die.

If they had 100% confidence in this property of black holes, why are they studying them?

They're not. They are looking for the particle(s) or properties that impart mass. Black hole formation is a (remote) possible side effect of the experiment.
The Higgs and the LHC

And yet, America is the only country I see consistently restricting themselves like this. Certainly in Britain, one pariliament can't set budget policy for the next, but projects don't have to rejustify funding every year and cancellations of large science projects are rare.

And when it comes to your Presidents... Doesn't Bush seem to be doing a good job of binding spending for the next president? If there is no money...

I'm sorry, but if you don't see other countries having funding problems, that says more about your own ignorance of the world at large than anything else... especially since you cite Parliament as a counterexample.

In actual fact, particle physics in the UK is facing a severe funding crisis

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.

Would it really "unify the people of Earth" ? Perhaps it may excite the Western First World nations but how would the US feel if an Iran/China coalition raced to Mars leaving the US looking on ? Rather than unification we would likely see mistrust and fear.

Let's look forward to the day when the international community actually works *together* on getting to Mars. We know it's possible. Taking any one counties flag into space won't unify, taking the human spirit into space will.

Some people have mentioned that relativity does not impose a maximum temperature, since although it has a maximum particle speed, kinetic energy and therefore temperature is infinite.

However, when you bring thermodynamics into it, things become more complicated.

Thermodynamics is derived from the statistical behavior of large collections of particles. The thermodynamic laws are derived from the partition function, which is a sum of the form exp(-beta E), where beta ~ 1/T is inverse temperature and E is the energy of a state of the system. The sum is over all the possible states.

In some systems, the number of states increases exponentially with energy, so the sum eventually diverges even though each term is an exponentially decaying function. The temperature at which this happens is the Hagedorn temperature mentioned in TFA. You can think of this situation as "entropy winning over energy", as the number of states determines the system's entropy.

In particular, in relativistic quantum field theory, relativity requires that it be possible to create particles matter-antimatter pairs if you put enough energy in the system.

One thing that can happen in some relativistic systems (though it doesn't have to happen) is that when you put enough energy into a system, it mostly goes into creating new particles instead of making existing particles go faster. Thus, the Hagedorn temperature: as you reach it, all the energy you're putting in to heat the system goes into particle production, and nothing goes into raising their temperature. (This is not the only way in which a system can have a Hagedorn limit, nor do all relativistic systems have this limit, but it can happen.)

TFA implies that this limit only exists in string theory. But it exists in other theories as well. For instance, quantum chromodynamics, the theory of the strong nuclear force, has a Hagedorn limit. But in QCD, it is thought that it's not a true maximum temperature. Rather, the divergence of the partition function there signals the presence of a phase transition, from quarks confined in hadrons to a free quark-gluon plasma. Perhaps in string gas cosmology it's a true limit; I don't know much about that.

If the entropy increases even faster than exponentially, you can get weird situations like negative heat capacities, i.e., where adding more energy to a system lowers its temperature! There, you actually take kinetic energy from existing particles and put it into particle creation, creating so many new particles that the overall temperature of the system decreases.

Incidentally, the beta factor mentioned above in the partition function explains another point in TFA, about negative temperatures. In statistical thermodynamics, you can see that the key parameter is not temperature T, but inverse temperature beta ~ 1/T. As you increase temperature towards infinity, beta decreases to towards zero from above, so hotter temperatures correspond to smaller betas. You can imagine how a negative beta, then, corresponds to an even hotter temperature than any positive beta. In other words, negative temperatures are hotter than positive temperatures. As beta is decreased smoothly through zero from above, temperature increases to positive infinity, jumps discontinuously to negative infinity, and then approaches zero temperature from the other side. The hottest temperature, then, is -0 K — or rather, the limit as you approach 0 K from below, instead of above (which is a different limit from the perspective of the more fundamental parameter beta).

For a little more about the Hagedorn temperature, read this historical essay and this paper (section 2). Wikipedia has a good discussion of negative temperature.

Err. No. We did *not* predict dark matter. We were not expecting dark matter or anything like it when the Zwicky first saw that there had to be some "more" matter in the galaxies to explain the observed rotational curves. He probably first said: "Gee, well, that looks funny!" Zwicky probably said something a lot better actually, as he was known for his, often rude, mannerisms.

The astonishing discoveries in science come when humans really have no clue what is coming next! Case in point: The November Revolution in Physics . That was the last time that the whole paradigm of understanding of particle physics shifted! That was back in 1974 and hasn't changed since! One new totally-unexpected particle, called the J/psi, was found and boom... the consequences were huge, for now, you *knew* that there had to more particles, namely the top and the bottom and that the W and the Z were predicted as well. Only after the discovery of all these predicted particles did the public came to accept the Standard Model and particle physics became a mature field. But, back in 1974, there were those who could see ahead in the light of this new discovery.

A large shift in the understanding of the universe happened already in astrophysics with the CMB(Cosmic Microwave Background) measurements. I liken it very much to the November Revolution. The CMB observations, first from COBE and later from WMAP and various other ground based observations, show with high statistics that there is something missing if we assume that the universe is all baryonic matter. Imagine a puzzle where there is a missing piece and now, you think of a piece that fits in this place. Well, dark matter fits the bill very well and other observations, also back it up. So somehow, dark matter is required by experimental results... Now, those who can see ahead make predictions on what we will --hopefully -- discover next: a dark matter candidate particle at the LHC, annihilation products of dark matter in space, a signal in gamma rays from annihilation, plenty of lensing examples in galaxies,.. This is called phenomenology for a reason. You get an idea inspired by experimental results from an experiment and look at what other phenomena you would observe in the light of your idea/theory.

End of my rant.

To put your "inexorableness" theory in perspective. There are more humans living on the planet right now, then has ever lived in total in the history of earth. So take humans and divide them into two groups: Group1: from the beginning of human evolution to 1920 and Group2: from 1920 to today. Group2 is significantly larger in population. Do you think Group2 achieved more? Really?!! I dont think so! I see most of the population watching TV and going to work where they try to minimize thinking! Group1 had to struggle more for survival and had to be more inventive to survive. The pressure is off on Group2. Laziness is settling in fast.

Yep that was shameful. Sadly, no one really batted an eyelid, almost like that's expected.

I'm guessing the whole dark matter, dark energy, "you want dark with that" industry will be incrementally debunked and the public is going to want their money back. Cooperstock and Tieu

I'd like to see a cartoon of scientists slapping high fives with the gods when one of their doomsday predictions finally comes through while mere mortals suffer, burn and drown. That's what we deserve for persecuting the scientists, you know, by giving them grant money, tenure, government jobs and the best tools money can buy.

Worst article ever.

Dark Matter particles come naturally from physics,

Dark Matter is an ad hoc theory. Dark Matter is made up crap and came directly from the ass of a physicist that drank too much snake oil. How does this guy's work differ? We'll never know from this article.

A non-Newtonian gravity theory is now fully specified on all scales by a smooth continuous function. It is ready for fellow scientists to falsify.

Describing a function with words is lacking at best. When I first read this I thought "they're poised to falsify data?"

The author uses words like: Legend, mystery, golden laws. I expect the headline below this article to say "Mr. Fuzzy Wuzzy weds Batman".

Dark Matter at odds with General Relativity

It appears that dark matter is not necessary to explain those observations. Someone just forgot to flip the gravity switch from "Newtonian" to "General Relativity" in the computer.

I really wish I had mod points right now. Even more convincing than the apparent non-necessity is its Trinity-like identity (it's three, and yet one; sphere, yet string; all, yet nothing).

That must be a great way to get tax dollars: ask for billions to research something that doesn't exist, and give it impossible characteristics.

It's real, it's a real great way to get money from the government for made up science.

Yes, that's my opinion, but this backs it up.

I want a refund.

Now, the slashdot community seems to be fairly educated and extremely opinionated so how about it--does dark matter exist? If so, since it is very difficult to detect, what are its defining properties?

If this is correct, then the Dark Matter riddle has been solved. Basically, it was due to the fact that scientists thought they could safely use the Newtonian limit to General Relativity with galaxies. They were wrong and Dark Matter is a result of this error.

This was reported on Slashdot not to many moons ago.

Simon

Seems pretty irrelevant as an end of year list to me too. For instance, significant progress has been made this year at debunking the entire homeopathy scam as woo-woo new age wishful thinking, plus they've found out that a lot less Dark Matter needs to exist in the universe if you simply apply the Einstein equations of relativity to the problem of spinning galactic discs instead of Newtonian physics equations.

CERN Courier says it could all be an error in calculation: http://www.cerncourier.com/main/article/45/8/8

It makes me sick to hear someone say "Dark Matter is out there you just can't see it." Well should I be listening for it? I hear Ozzy Osbourne can taste the shit when he's flying high. What a stupid farce and the public should demand all there money back from theose egotistical jerks.

Some weird science type guys stopped light in an experiment recently http://www.cerncourier.com/main/article/41/3/10/. Supercooled gas might be a bit difficult to find, except if you're canadian.

It is long waited prize in the the High Energy Physics comunity. It wasn't awarded before because some dispute about the original idea claimed by Gerard T'Hooft but never published. Only after T'Hooft got the nobel prize in 1999 the path to the "QCD nobel prize" was really open.

The ultimate goal is reaching a theoretical Island of Stability.

This is a hypothesized region farther down on the peiodic table where extremely heavy elements become stable and long-lasting, albeit with interesting properties due to the large number of sub-elements of which they're comprised.

These will most likely be primarily used by academic institutions, such as CERN, NASA, and universities who are lucky enough to own particle accelerators. CERN has several petabytes of storage currently, which are housed in silos full of tapes, with rather funky robots which fly around at speed. An average particle collision (single experiment!) will give at least 1GB of data, which will take a considerable amount of time to process into something more managable, and therefore needs storing.
All in all, I think they'll have a few interested clients, but at the same time, most places where they have minds capable of building machines of the magnitude used for these experiments, they tend to be more than capable of building solutions similar to this.

Take a look at this!

You'd have to sit all day measuring length and curvature of particle tracks

Nowadays the task is (of course) left to computers but back then it was done by female office workers, many of them now married to particle physicists...

Actually "computer" used to mean a person, not a machine. Pretty boring I guess - read "Bridge over River Kwai" for an example.

I know I am going to be flamed for this, but this very topic is discussed at extreme length in Stephen Wolfram's book, "A New Kind of Science". He specifically goes on end about a particular one-dimensional cellular automata, "rule 110" (IIRC), which seems to produce randomness, but which is based off of a small handful of simple rules, and a base starting condition of a single black pixel. He demonstrates in excruciating detail how, no matter how complicated you make a system, that all such systems can be brought back to the set of simple one-dimensional CAs. He demostrates how Turing machines can be set up (via initial starting conditions - not just a single pixel) which use these same CA to perform Turing machine calculations - thus these same CA can, in theory, execute (albeit very slowly) and emulate any current computer or program in existance today. He names this "the principle of computational equivalence".

He explores at great length how systems that are seemingly random can actually be simulated by these self-same CAs, which are based on simple sets of rules - blowing away the time-held notion that complexity arises from an underlying complex ruleset. It stands to reason that given the ruleset, and a result output from the CA, one can work back to the initial starting conditions - the problem arises in that we may only have the initial conditions, figuring out that ruleset is (probably) impossible.

He explores our current methods of perception and analysis, and shows how while our current methods of analysis show that something is random, as humans using our senses we have an affinity for picking out what look to be like patterns - he seems to make the point (unless I have misinterpreted him - which is very likely) that it isn't our senses decieving us, it is our methods of analysis that are incomplete. He also presents ideas and thoughts on how we can overcome these limitations.

The book is much more than that, however - I have read articles dismissing the work as everything from a form of plagerism (at worse) to restating others thoughts (at best). I do not believe this is the case. While it is true many others in the past have played with CAs, what Wolfram has done is go that extra step, building on these ideas and bringing them all together under one umbrella of thought. He acknowledges this throughout the book.

Anyone interested in these topics and others tangent to them owes it to themselves to read Wolfram's book and come to their own conclusions. I honestly believe he is on to something, which could have profound effects in the future (perhaps far in the future, but much sooner if we read it and understand it now).

Other related links:

Collection of Reviews on ANKOS
Stephen Wolfram's Web Site
ANKOS Web Site

I thought the index of refraction was defined as:

n = (speed of light in vacuum)/(speed of light in medium),

another definition, IIRC, is c/sqrt(mu*epsilon)

mu = permeability
epsilon = permittivity

both are coeeficients of the linear response of meterials to the EM field.

now, if the linear response of a material to EM fields is complex, I guess you can have negative (or imaginary) n.

imaginary means exponential decay or growth, BTW, but of course in the case of growth the material stops responding linearly at some point, thus changing the dependance.

IIAC, negative n does not really mean the speed of light reverses .

Now, convenctional wisdom and all modern science says c is always the bigger value, so n is always >= 1

AFAIK you're right in saying c is always the bigger value, however there exist superluminal photons , which have phase velocity higher than c.

This is not, again AFAIK, related to the response medium but to other quantum phenomenas.

The universe can do some weird, convoluted vodoo ...

There's this article I found... some people have developed ways to cool silicon using nothing but silicon! Here's the article. I remember also a little side article about refrigerating silicon (the silicon acts as a active heat dissipater) in Popular Science a few issues back but I'm too lazy to dig through my room or do a web search.