Photographic Dark Matter

[TalonThorn]

They say it's out there and they'll have photos to prove it, so you EU guys better prepare yourself...

http://www.wired.com/magazine/2009/12/s ... gy_camera/

I wonder what they'll say when the photographs come out blank...or do you suppose they'll come up with some EU event and dub it dark matter disturbances? Hmmm.

[junglelord]

Really nice device, 35 million...good for galactic research, but really, they do talk in circles.

Of course, we don’t really know whether dark energy even exists. What we do know is that the universe has been expanding since the big bang. But rather than slowing down like everything else fighting gravity’s pull, this expansion seems to be speeding up. Something must be causing this, and astronomers call that something dark energy

[starbiter]

I could really use a camera like this to take pictures of rocks in the desert. I could take 570 meg shots, and then reduce them to 50 k for the forum.

michael

Just kidding. I'm greatful.

[Biggins]

From my understanding they are just looking at normal galaxies and getting the redshifts for them. It would appear to be effectively a ground-based Hubble.

[jjohnson]

"photographing dark matter and energy" is a great oxymoron as, by definition, they are not detectable in the E/M spectrum. -at least as I understand their descriptions. However, we cannot 'see' radio waves, X rays or UV 'light', either, until it is detected by suitable instruments and rendered in false (i.e., visible to us) color so that it is perceptible. And, of course, no one can 'see' gravity except by its imputed effects. Radio telescopes routinely image "dark energy", and we see their images posted on the NRAO site, and Jodrell Bank and others all the time. If they are going to do more than infer the presence of "their dark materials" then they are going to have to do better than make theoretical, mathematical inferences. Revealing matter and energy which do not interact with the E/M spectrum, where our senses and technology are versatile, is going to take some fancy maneuvering, but the observations and measurements should come before the theoretical math, not the other way round.

I don't see the difference between what Tom Bridgeman derides in the EU as "cartoons" and what NASA calls "artist's interpretation" of hypothetical ideas, except that NASA's renderings don't come in for derisive comments from Mr. B.

Jim

[nick c]

From the article:

The hope is that scientists can use detailed photos to chart the light from galaxies and supernovas, which will show the growth of the cosmos and at least give them more evidence for the existence and effect of dark energy.

Gathering data and interpreting data (within a theoretical context) are two different things

Nick

[jjohnson]

Indeed they are, Nick! In fact, given all the data assembled before us today, it is the interpretation of those data sets that differentiate the Electric Model from the Gravity Model. We see two rather different universes as a result. The name of dat tune be "Reconciliation Blues".

[Harry Costas]

G'day

You may find this paper interesting.

Dark Matter Axions
00/2010
http://adsabs.harvard.edu/abs/2010IJMPA..25..554S
http://adsabs.harvard.edu/cgi-bin/nph-d ... db_key=PHY

The hypothesis of an 'invisible' axion was made by Misha Shifman and others, approximately thirty years ago. It has turned out to be an unusually fruitful idea, crossing boundaries between particle physics, astrophysics and cosmology. An axion with mass of order 10-5 eV (with large uncertainties) is one of the leading candidates for the dark matter of the universe. It was found recently that dark matter axions thermalize and form a Bose-Einstein condensate (BEC). Because they form a BEC, axions differ from ordinary cold dark matter (CDM) in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles. Because there is evidence for these phenomena, unexplained with ordinary CDM, an argument can be made that the dark matter is axions.

and

Searching for Axions and Other Exotics with Dark Matter Detectors
00/2010
http://adsabs.harvard.edu/abs/2010IJMPA..25..564P

I consider models of light super-weakly interacting cold dark matter, with O(10) {keV} mass, focusing on bosonic candidates such as pseudoscalars and vectors. I analyze the cosmological abundance, the γ-background created by particle decays, the impact on stellar processes due to cooling, and the direct detection capabilities in order to identify classes of models that pass all the constraints. In certain models, variants of photoelectric (or axioelectric) absorption of dark matter in direct-detection experiments can provide a sensitivity to the superweak couplings to the Standard Model which is superior to all existing indirect constraints. In all models studied, the annual modulation of the direct-detection signal is at the currently unobservable level of O(10-5).

and


The search of axion-like-particles with Fermi and Cherenkov telescopes
Jan-10
http://adsabs.harvard.edu/abs/2010arXiv1001.1892S
http://adsabs.harvard.edu/cgi-bin/nph-d ... db_key=PRE

Axion Like Particles (ALPs), postulated to solve the strong-CP problem, are predicted to couple with photons in the presence of magnetic fields, which may lead to a significant change in the observed spectra of gamma-ray sources such as AGNs. Here we simultaneously consider in the same framework both the photon/axion mixing that takes place in the gamma-ray source and that one expected to occur in the intergalactic magnetic fields. We show that photon/axion mixing could explain recent puzzles regarding the observed spectra of distant gamma-ray sources as well as the recently published lower limit to the EBL intensity. We finally summarize the different signatures expected and discuss the best strategy to search for ALPs with the Fermi satellite and current Cherenkov telescopes like CANGAROO, HESS, MAGIC and VERITAS.

Since the ABS are self explaining, I thought I would not add my opinion or an explanation.

[nick c]

Hi Harry,
Let's see,
Dark Matter is a hypothetical type of matter used to explain anomalous galactic rotations....
Axions are a hypothetical elementary particle needed to resolve problems in quantum physics....
From my layman's pov, using a hypothetical to explain another hypothetical does not inspire a great deal of confidence.

I like the EU explanation much better, simple and effective, no Dark Matter needed.

Nick

[Harry Costas]

G'day

Dark Matter/Energy as defined by the BBT is very theoretical and contextual.

Axions and related subatomic particles give us some understanding of the dynamics of condensed matter and from this we can understand the electrics, electromagnetis fields and filaments that we observe in the electric universe. This is the missing link, just avoiding it leaves out the critical understanding that the electric universe is searching. Dark matter in this case is subatomic preon particle matter within the nucleus of the atom.

I'm posting the following link not to prove a point but to have information on the topic.

Topologically induced local PandCP violation in QCD × QED
Jan-10
NASA
http://adsabs.harvard.edu/abs/2010AnPhy.325..205K
arXiv
http://adsabs.harvard.edu/cgi-bin/nph-d ... db_key=PHY

The existence of topological solutions and axial anomaly open a possibility of PandCP violation in QCD. For a reason that has not yet been established conclusively, this possibility is not realized in strong interactions – the experimental data indicate that a global PandCP violation in QCD is absent. Nevertheless, the fluctuations of topological charge in QCD vacuum, although not observable directly, are expected to play an important rôle in the breaking of UA(1) symmetry and in the mass spectrum and other properties of hadrons. Moreover, in the presence of very intense external electromagnetic fields topological solutions of QCD can induce localP-andCP-odd effects in the SUc(3)×Uem(1) gauge theory that can be observed in experiment directly. Here I show how these local parity-violating phenomena can be described by using the Maxwell–Chern–Simons, or axion, electrodynamics as an effective theory. Local P-andCP-violation in hot QCD matter can be observed in experiment through the “chiral magnetic effect” – the separation of electric charge along the axis of magnetic field. Very recently, STAR Collaboration presented an observation of the electric charge asymmetry with respect to reaction plane in relativistic heavy ion collisions at RHIC.

[junglelord]

Dark Matter, Harry Potter....same thing, its all fantasy.

[Harry Costas]

G'day Junglelord

Smile,,,,,Harry Potter

I prefer not to use the term Dark Matter, you are right the term labels it as fantasy.

Regarless the direction of research in the past 2 years has been towards these basic particles creating a dilaton with a spin explaining the formation of jets where the ejection gets close to the speed of light.

The vector fields created by such condensed matter explains how light partilces can reach the speed of light. Once the phase changes the gravitaional field slows it down forming knots as can observe eg M87.

For further ABS that will allow you to get the GIST of it.
Starting with the year 2010

Axion Dark matter 2010
http://adsabs.harvard.edu/cgi-bin/basic ... &version=1

Please do not get this type of Dark matter confused with the Fantasy Dark matter as per the Big Bang Theory.

[jjohnson]

Hi, Harry,
Thank you for the references - some of the papers are found in PDF format on arXiv which is very helpful.
I might add for all of us to consider that I do not know what axions are, but am trying to learn, and because of this I do not make any personal arguments pro or con, and the fact that someone knows or doesn't know what the researchers mean by this is irrelevant to whether or not this is a fruitful path. Therefore, I have to assume it is a fruitful path, because, if I don't, I've dismissed it out of hand, something that I dislike about what I read in so many establishment papers.
I read the first paper I ran across, CDMS-II to SuperCDMS:WIMP...etc by Tobias Bruch, reporting on the types of detectors and the goals of an experimental setup in Soudan, Minnesota USA. Here is the first part of their Conclusion summary:

5 Summary
The CDMS-II experiment has maintained high dark matter discovery potential by limiting expected backgrounds to less than one event in the signal region. The current data sets the world’s most stringent upper limit on the spin-independent WIMP-nucleon cross-section for WIMP masses above 42 GeV/c2 with a minimum of 4.6 × 10−44 cm2 for a WIMP mass of 60 GeV/c2. The analysis of a dataset with a factor of 2.5 more Ge exposure is ongoing, it is expected to increase the sensitivity to the low 10−44 cm2 range.

[Font colour emphasis mine]

I am reminded by this wording of the recent wording of the recent results of the LIGO detector, looking for signs of gravitational waves. The first thing that both reports mean is that no results were forthcoming in terms of having reliably detected what they are looking for. While that sounds bad, it is not necessarily a falsification of anything; only that at their detector's current level of sensitivity, the expected or hoped-for results aren't being found. That could be due to a lot of things, ranging from "no such things exist" to "they exist but they are so rare that the run-time was too short to have encountered any detectable events" to "the next improvement in detector sensitivity and resolution (zeptoBarns for the enthusiasts of cross-section probabilities) will uncover the desired signatures."

The last statement is likely the hope and impetus for additional funding. I'll avoid being cynical here, since that works against being as fair and open-minded as I can. If this group detects what they are looking for it might lead to a more fundamental understanding at a rather deep level of how things work, and heaven knows I'm for that. I try to stick to just understanding how stars work, since I'm a damned architect by training, not an astrophysicist, but eventually we're going to want to know it all, have no doubt.

Harry , here's a semantic question which I haven't found explained yet - what is meant by "annual signal modulation"? Is "annual" the same as "annular" as in an equatorial toroidally located signal generation, or is this some sort of temporal adjective, as in "once a year" periodicity? The latter seems unlikely, while the former seems a misspelling, as annular comes from the Latin word for "ring" while annual comes from the Latin word for "year". A ring form in the EU context is quite familiar, but I am unfamiliar with it in the subatomic particle context. Help. And thanks for keeping on us about learning from existing papers - we need our ideas, as any scientist knows, to be on as firm ground as practicable.

Jim

[junglelord]

on the other side of the coin I found this today.

An underground experiment may have detected a type of dark-matter particle.

Deep in the Soudan mine in Minnesota, some 700 metres below ground amid the bones of bats, sits the huge Cryogenic Dark Matter Search (CDMSII) experiment, which at its heart contains a rack of supercooled hockey-puck-sized silicon and germanium detectors nestled within Russian-doll layers of shielding.

Two weeks ago, the CDMSII collaboration published a paper showing that two particles had penetrated its detector's defences — particles that, given the lack of any other particle activity down in the frigid quiet of the detectors, looked very much like dark matter1. Dark matter is thought to make up 85% of the mass in the Universe, but has not been detected directly — quite. The attention-grabbing claim of the CDMSII collaboration has many physicists thinking — but not yet convinced — that the team could be on to something.

Just a stone's throw from the CDMSII experiment, across the subterranean cavern, lies a far smaller box that is thickening the dark-matter plot. The box contains a single germanium hockey puck, similar to those in the CDMSII experiment but operated by the Coherent Germanium Neutrino Technology (CoGeNT) collaboration and tuned to detect incoming particles with much lower masses than the CDMSII. It began collecting data in December 2009, and, after just 56 days, the group is reporting hundreds of particle strikes that cannot be explained other than by invoking dark matter.

"If it's real, we're looking at a very beautiful dark-matter signal," says Juan Collar, a physicist at the University of Chicago and CoGeNT spokesperson. Collar presented the work today at a dark-matter conference at the University of California, Los Angeles. The results were posted on the preprint server Arxiv yesterday2.

Confirmation of the result — and Collar is careful to say that it is still early days — would radically shift attention to experiments that are sensitive to lower energies. The CoGeNT experiment looks for a type of dark-matter particle called a WIMP, or Weakly Interacting Massive Particle. The new data point to a WIMP with a mass in the range of 7–11 billion electronvolts. Theorists have conjured up hundreds of mathematically consistent models for producing WIMPs of different masses in the early Universe, and the particles detected by CoGeNT fit well in the realm of the theoretically possible.

But the majority of models had favoured WIMP particles that are an order of magnitude heavier, and some experiments — such as the CDMSII, and those using large tanks filled with mineral oil or liquefied noble gases — were aiming for that territory. "The experiments designed to look at the heavier particles aren't going to like the CoGeNT result," says Dan Hooper, a theorist at the Fermi National Accelerator Laboratory in Batavia, Illinois.

Swimming in dark matter
On its own, the CoGeNT result is just yet another tentative claim in a sea of dark-matter hints. And Collar himself acknowledges that the CoGeNT detector is not shielded as well as the CDMSII experiment, so the signal he's seeing could simply be an unexplained radioactive decay process in the electronics. But the fact that the CoGeNT results mesh so well with those of the CDMSII and one other experiment is what gets the attention of Neal Weiner, a theorist at New York University. "I think this will make some noise," says Weiner. "It lines up nicely with the possible interpretation of other results."

The WIMP called for by the CoGeNT result is consistent with the two CDMSII 'hits', but because those events lay at the lower reaches of CDMSII's energy sensitivities, researchers will have a hard time sifting for more.
The second experiment that matches up with the CoGeNT result is the strange signal seen in a deep underground detector in Gran Sasso, Italy, by the DAMA/LIBRA collaboration (Dark Matter Large Sodium Iodide Bulk for Rare Processes) (see 'Italian group claims to see dark matter - again'). For a decade, the Italian team has found a periodic signal that won't go away; the effect has been put down to Earth annually passing through a steady current of dark matter in the Milky Way.

The particles seen by CoGeNT are much lower in mass than the regions of parameter space currently being investigated by space satellites such as the Fermi Gamma-ray Space Telescope and the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), which have also found dark matter hints — but for heavier particles (see 'Dark matter intrigue deepens').

But Weiner points out that whereas the CoGeNT result will raise doubts about what the space experiments are seeing, they won't undermine them completely; it's entirely possible that all of the dark matter seen indirectly in the cosmos could be comprised of both light and heavy particles. So he doesn't want the planned higher-mass detectors to be mothballed just yet. "This won't put any of the detectors out of business," says Weiner. "We should be cautious."

http://www.nature.com/news/2010/100226/ ... 10.97.html

funny how in the end they should be cautious.....good cover to keep the "business" going.

[Harry Costas]

G'day
Re: Annual

DAMA/NaI
http://en.wikipedia.org/wiki/DAMA/NaI

The DAMA/NaI experiment[1] was designed to detect dark matter using the direct detection technique. It was located at the Laboratori Nazionali del Gran Sasso in Italy and collected data during the period 1996-2002. Its successor is the DAMA/LIBRA experiment, which uses very similar detector technology but has a larger target mass of 250 kg.

The DAMA/NaI set up consisted of 9 scintillating thallium-doped sodium iodide (NaI) crystals of 9.7 kg each. Electrons and nuclei recoiling after a collision cause emissions of photons that are detected using photomultiplier tubes. A detected recoil can be caused by dark matter particles or by the background (thermal neutrons, radioactivity or cosmic radiation). The revolution of the Earth around the Sun causes an annual modulationof the dark matter flux. This should give rise to an annual modulation in the detected recoils and thus provides a simple way to extract a dark matter signal from the background.

The DAMA/NaI experiment has used this technique and is the only one to have reported a positive signal. The results of this experiment are controversial because other searches have not detected nuclear recoils due to dark matter interactions. All these other searches use sophisticated background elimination techniques instead of the annual modulation technique.

For weakly interacting massive particles (WIMP) interacting with nuclei through spin independent interactions, the available parameter space consistent with DAMA and all other experiments is very limited.[2] The case of spin dependent interactions is studied in three papers.[3][4][5] Inelastic dark matter,[6] mirror matter,[7] self-interacting dark matter,[8] scalar and pseudoscalar dark matter[9] and fourth generation neutrinos[10][11] have also been proposed as possible explanations for the DAMA signal.

Weakly interacting massive particles
http://en.wikipedia.org/wiki/Weakly_int ... _particles

Another way of detecting atoms "knocked about" by a WIMP is to use scintillating material, so that light pulses are generated by the moving atom. The DEAP experiment plans to instrument a very large target mass of liquid argon for a sensitive WIMP search at SNOLAB. Another example of this technique is the DAMA/NaI and DAMA/LIBRA detector in Italy. It uses multiple materials to identify false signals from other light-creating processes. This experiment observed an annual change in the rate of signals in the detector. This annual modulation is one of the predicted signatures of a WIMP signal,[11][12] and on this basis the DAMA collaboration has claimed a positive detection. Other groups, however, have not confirmed this result. The CDMS and EDELWEISS experiments would be expected to observe a significant number of WIMP-nucleus scatters if the DAMA signal were in fact caused by WIMPs. Since the other experiments do not see these events, the interpretation of the DAMA result as a WIMP detection can be excluded for most WIMP models. It is possible to devise models that reconcile a positive DAMA result with the other negative results, but as the sensitivity of other experiments improves, this becomes more difficult. The CDMS data taken in the Soudan Mine and made public in May 2004 exclude the entire DAMA signal region given certain standard assumptions about the properties of the WIMPs and the dark matter halo.