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Newly released research has identified the existence of a giant cosmic accelerator above the Earth--a casual space "synchrotron accelerator" has scales of hundreds of thousands of kilometers, dwarfing even the largest man-made similar accelerators such as the Large Hadron Collider at CERN, which has a circumference of only 27 kilometres.

Mann says this particle accelerationderiving energy from solar flares or eruptions and carried through space on a solar windexists in the region of space dominated by the Earths magnetic field, where satellites fly, known as the magnetosphere. The discovery is a jumping-off point for understanding space storms and determining how to protect man-made systemson Earth and in spacefrom potential damage from space storms and severe space weather.

"The puzzle ever since their discovery has been how do the particles get accelerated up to nearly the speed of light?" said Mann.

Mann says this highly relativistic particle acceleration, which can damage satellites and pose a risk to astronauts during space weather storms, is akin to the relationship between a surfer and a wave, in that the particles repeatedly catch a "ride" on a wave that sends them rocketing around the planet. As they circle the Earth, the particles may be picked up again by the same wave, which will boost its speed even further. The result is a perpetual term wherein the particles "get repeatedly accelerated by waves that are coherent on truly planetary scales spanning hundreds of thousands of kilometers," Mann said.

And like climatic weather storms, space storms can be anywhere from mild to powerful. Mann says these solar storms can have assortment of effects on technological infrastructure on Earth, from mild disruption of satellite communications to widespread damage of telegraph systems as occurred during the Carrington solar storm of 1859, manifested on Earth as bright Aurorae seen across the globe.

"Theres eyewitness accounts published in newspapers of telegraph wires setting on fire as a result of the electrical currents that were driven into ground infrastructure due to these space weather storms," said Mann, adding that the potential damage from a similar-sized space storm in todays highly technological world has been forecast to cost trillions of dollars in loss and repair.

Mann says understanding the physics of space weather is still in the discovery phase, but with results such as this, researchers are moving closer to producing more accurate space weather forecasts.

"Were still trying to piece together what a really big space storm would look like, and the impact that it might have on infrastructure such as operating satellites and ground power networksand ultimately trying to improve some of our protection of those systems against severe space weather," said Mann. "With this discovery, were starting to put the pieces together to understand how this radiation might be created and, therefore, understand how extreme the response to severe space storms might be."

The Daily Galaxy via University of Alberta

Image credit: NASA Solar Dynamics Observatory

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The discovery of dark matter means we would have identified the dominant form of matter in the universe that seeded structure and led to galaxies, solar systems and planets, and ultimately to our Earth with intelligent life. In late February, dark matter hunters from around the world gathered at the University of California, Los Angeles for Dark Matter 2014 --the unknown stuff that makes up more than a quarter of the universe yet remains a mystery.

So where does the hunt stand? Between sessions, three paramount physicists at the conference spent an hour discussing its biggest highlights and prospects for future progress.

Blas Cabrera Professor of Physics at Stanford University, and Member of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford. Spokesperson for the SuperCDMS dark matter experiment. Dan Hooper Scientist in the Theoretical Astrophysics Group at the Fermi National Accelerator Laboratory, Associate Professor in the Department of Astronomy and Astrophysics at the University of Chicago, and Senior Member of the Kavli Institute for Cosmological Physics (KICP) at UChicago. Tim Tait Professor of Physics and Astronomy at the University of California Irvine, and Member of UC Irvines Theoretical Particle Physics Group.

The following is an edited transcript of the discussion led by the Kavli Foundation at Stanford University. The Kavli Foundation supports paramount science aimed at understanding the origin, structure and composition of the cosmos.

THE KAVLI FOUNDATION: Almost everyone at the conference seems to ponder were finally on the path toward figuring out what dark matter is. After 80 years of being in the dark, what are we hearing at this meeting to explain the optimism?

Why are scientists optimistic about figuring out what dark matter is?

What is the latest for researchers looking for evidence of supersymmetry, which could broadcast the mood of dark matter?

Has anything discussed at this meeting convinced you which approach will be the first to identify dark matter?

What would a confirmed detection of dark matter really mean for what we know about the universe?

BLAS CABRERA: This conference has highlighted the progression of larger and larger experiments with remarkable advances in sensitivity. What were looking for is evidence of a dark matter particle, and the paramount idea for what it might be is something called a weakly interacting massive particle, or WIMP. We believe the WIMP interacts with ordinary matter only very rarely, but we have hints from a few experiments that might be evidence for WIMPs.

Separately at this conference, we heard about improved calibrations of last falls results from LUX, the Large Underground Xenon detector that now leads the world in sensitivity for WIMPs above the mass of six protons a proton being the nucleus of a single hydrogen atom. Under a standard interpretation of the data, the LUX team has ruled out a anger of low-end masses for the dark matter particle, another major advance because it does not see potential detections reported by other experiments and further narrows the possibilities for how massive the WIMP might be.

Finally, Dan [Hooper] also gave a remarkable presentation here about another effort: to indirectly detect dark matter by studying radiation coming from the center of the Milky Way galaxy. He reported the possibility of a strong dark matter signal, and I would say that was also one of the highlights of the conference because it provides us with some of the strongest evidence so far of a dark matter detection in space. Dan can explain.

In the image below, Gamma-ray photons seen emanating from the center of the Milky Way galaxy are consistent with the intriguing possibility that dark-matter particles are annihilating each other in space, according to research conducted by UC Irvine astrophysicists. Analyzing data collected between August 2008 and June 2012 from NASAs Fermi Gamma-ray Space Telescope orbiting Earth, the team found more gamma-ray photons coming from the Milky Way galactic center than they had expected, based on previous scientific models.

DAN HOOPER: Four and a half years ago, I wrote my first paper on searching for evidence of dark matter at the center of the Milky Way galaxy. And now we ponder we have the most compelling results to date. What were looking at is actually gamma rays the most energetic form of light radiating from the center of the galaxy. I ponder that this is very likely a signal of annihilating dark matter particles. As Blas explained, we believe dark matter is made of particles, and these particles, by themselves, are expected to be stable meaning that they dont readily decline into other particles or forms of radiation. But at the dense core of the Milky Way galaxy, we ponder they collide and annihilate one another, in the process releasing huge amounts of energy in the form of gamma rays.

TIM TAIT: We expect that the density of dark matter particles, and therefore the fervor of the gamma-ray radiation released when they collide, should both fall as you move away from the galactic center. So, you sort of know what the profile of the signal should be, moving from the center of the galaxy outward.

TKF: So Dan, in this case the gamma rays that we notice radiating from the center of the Milky Way agree our predictions for the mass of dark matter particles?

HOOPER: Thats right. We predicted what the energy level of the gamma rays should be, based on established theories for how massive the WIMP should be, and what weve seen matches the simplest theoretical model for the WIMP. Our paper is based on more data, and we found more sophisticated ways of analyzing that data. We threw every test we could ponder of at it. We found that not only is the signal there and very statistically distinctive, its characteristics really look like what we would expect dark matter to produce in the way that the gamma-ray radiation maps on the sky, in its general brightness, and in other features.

TKF: Tell me a bit more about this prediction.

HOOPER: We ponder that all the particles that make up dark matter were all produced in the Big Bang nearly 14 billion years ago, and eventually as the universe cooled a small fraction survived to make up the dark matter we have today. The amount that has survived depends on how much the dark matter particles have interacted with one other over cosmic time. The more they collided and became annihilated, the less dark matter survives today. So, I can basically calculate the rate at which dark matter particles have collided over cosmic history based on how much dark matter we predict exists in the universe today. And once I have the rate of dark matter annihilation today, I can predict how bright the gamma-ray signal from the galactic center should be if its made of WIMPS of a certain mass. And lo and behold, the observed gamma-ray signal is as bright as we predict it should be.

TKF: What else caught everyones attention at the conference?

TAIT: A really striking result was from Super Cryogenic Dark Matter Search, or SuperCDMS, the direct detection experiment that Blas works on. They didnt find any evidence for dark matter, and that contradicts several other direct detection experiments that have claimed a detection in the same mass anger.

CABRERA: What were looking for is an exceedingly rare collision between an incoming WIMP and the nucleus of a single atom in our detector, which in SuperCDMS is made from germanium crystal. The collision causes the nucleus of a germanium atom to recoil, and that recoil generates a small amount of energy that we can measure.

Direct detection experiments are situated underground to minimize background noise from a assortment of known sources of radiation, from space and on Earth. The new detectors that we built in SuperCDMS have allowed us to reject the dominant background noise that in the past clouded our ability to detect a dark matter signal. This noise was from electrons hitting the surface of the germanium crystal in the detector.

The new plan allows us to clearly identify and throw out these surface events. So, rather than saying, Okay, maybe this background could be partly a signal, we can say with confidence now, There is no background and you have a very clean result. What this means is we have much more confidence in our data if we do make a potential detection. And if we dont, were more trustful that were coming up exhaust. Eliminating background noise vastly reduces uncertainties in our analysis whether we find something or not.

A tiny fraction of the x-rays in the image below of the central area of the Andromeda galaxyobtained with NASAs spaceborne Chandra X-ray Observatorycould originate from dark matter.

TKF: What caught everyones attention on the theoretical side?

CABRERA: What struck me at this meeting is that nuclear physicists have recently written papers describing a generalized framework for all possible interactions between a dark matter particle and the nucleus of a single atom of the material that researchers use in their detectors; in the case of SuperCDMS, as Ive explained, its germanium and silicon crystals. These nuclear physicists have pointed out that roughly half of all possible interactions are not even being considered now. We are trying to digest what that means, but it suggests there are many more possibilities and a lot we still dont know.

TKF: Tim, with accelerators like the Large Hadron Collider in Europe, researchers are looking for evidence of supersymmetry, which could broadcast the mood of dark matter. Tell me about this idea. Also, was anything new discussed at the meeting?

TIM TAIT: Supersymmetry proposes there are mirror particles that shadow all the known basic particles, and in this shadow world may lurk the dark matter particle. So, by smashing together protons in the LHC, weve tried to broadcast these theoretical supersymmetric particles. So far, though, the LHC hasnt found any evidence for supersymmetry. It may be that our vision of supersymmetry isnt the only vision for physics beyond the Standard Model. Or maybe our vision for supersymmetry isnt a complete one.

TKF: The LHC is going to collide protons at much higher energy levels next year, so could that broadcast something we just cant see right now?

TAIT: We hope so. We have very good excuse to ponder that the lightest of the mirror particles in this shadow family is probably stable, so higher energy collisions could very well broadcast them. If dark matter was formed early in the universe as a supersymmetric particle and its still around which we ponder it is it could show up in the next round of LHC experiments.

TKF: When you ponder about the different approaches to identifying dark matter, has anything discussed at this meeting convinced you that one of them will be first?

TAIT: When you look at all the different ways of looking for dark matter, what you find is that they all have incredible strengths and they all have blind spots. And so you cant really say one is doing better than the other. You can say, though, they are answering different questions and doing very distinctive things. Because even if you end up discovering dark matter in one place lets say in the direct detection search the fact that you do not see it at the LHC, for example, is already telling you something amazing about the theory. A negative result is actually just as distinctive as a positive result.

When you look at all the different ways of looking for dark matter, what you find is that they all have incredible strengths and they all have blind spots.

HOOPER: The same goes with the direct detection experiments. Im remarkably surprised that they havent seen anything. We have this idea of where these supersymmetric particles and WIMP particles should show up in these experiments at the LHC and in direct detection experiments and yet lo and behold we got there and they are not there. But that doesnt mean theyre not right around the corner, or maybe several corners away.

CABRERA: Given the remarkable progress over the past few years with many direct detection experiments, we would not have been surprised to have something rear its head that looks like a true WIMP.

Excess gamma raysImage of excess gamma rays seen around the center of the Milky Way galaxy, detected by the Fermi Gamma-Ray Space Telescope. (Credit: The Characterization of the Gamma-Ray Signal from the Central Milky Way: A Compelling Case for Annihilating Dark Matter, Daylan et al., arXiv:1402.6703v1 [astro-ph.HE] 26 Feb 2014.)

HOOPER: Similarly, I ponder if you had done a survey of particle physicists five years ago, I dont ponder many of them would have said that in 2014 weve only discovered the Higgs the basic particle that imparts mass to basic particles and not anything else.

CABRERA: Now that the Higgs has been pretty convincingly seen, the next big questions for the accelerator community are: What is dark matter? What is it telling us that we do not see dark matter at the LHC? What does that leave open? These questions are being asked broadly, which wasnt the case in past years.

TKF: Was finding the Higgs, in a sense, an easier quest than identifying dark matter?

HOOPER: We knew what the Higgs should look like, and we knew what we would have to do to notice it. Although we didnt know exactly how heavy it would be.

CABRERA: We knew it had to be there.

HOOPER: If it werent there it would have been weird. Now, with dark matter, there are hundreds and hundreds of different WIMP candidates that people have written down, and they all behave differently. So the Higgs is a singular idea, more or less, while the WIMP is a whole class of ideas.

TKF: What would a confirmed detection of dark matter really mean for what we know about the universe? And where would we go from there?

CABRERA: A discovery of dark matter with direct detection experiments would not be the end of the journey, but rather the beginning of a very exciting set of follow-up experiments. We would want to determine the mass and other properties of the particle with more precision, and wed also want to better understand how dark matter is distributed in and around our galaxy. Follow-up experiments with detectors would use different materials, and wed also try to map which direction the WIMPs are coming from through our detectors, which would help us better understand the mood of dark matter that surrounds the Earth.

Overall, a discovery would be huge for astrophysics and cosmology, and for elementary particle physics. For astrophysics we would have identified the dominant form of matter in the universe that seeded structure and led to galaxies, solar systems and planets, and ultimately to our Earth with intelligent life. On the particle physics side, this new particle would require physics beyond the Standard Model such as supersymmetry, and would allow us to probe this new sector with particle accelerators like the LHC.

The history of science is full of discoveries opening up whole new avenues for exploration that were not foreseen.

TAIT: I ponder theres a lot of different ways you could look at it. From a particle physicists point of belief, we would now have a new particle that wed have to put into our basic table of particles. We know that we see lots of structure in this table, but we dont really understand where the structure comes from.

From a practical point of belief, and this is very speculative, dark matter is a frozen form of energy, right? Its mass is energy, and its all around us. Personally, if I understood how dark matter interacts with ordinary matter, I would try to figure out how to build a reactor. And Im sure that such a thing is not at all practical today, but someday we might be capable to do it. Right now, dark matter just goes right through us, and we dont know how to break it and communicate with it.

HOOPER: That was awesome, Tim. You blow my mind. Im picturing a 25th century culture in which we harness dark matter to make an entirely new form of energy.

TAIT: By the way, Dan, Im toying with the idea of writing a paper so we should detain talking.

HOOPER: I would love to hear more about it. That sounds great. So, to kind of echo some of what Tim said, the dark matter particle, once we identify it, has to fit into a bigger theory that connects it to the Standard Model. We dont really have any idea what that might look like. We have a lot of guesses, but we really dont know so theres a lot of labor to do. Maybe this will help us build a grand unified theory a single mathematical explanation for the universe and help us, for example, understand things like gravity, which frankly we dont understand at all in a particle physics context. Maybe it will just open our eyes to entirely new possibilities that we just never considered until now. T

The history of science is full of discoveries opening up whole new avenues for exploration that were not foreseen. And I have every excuse to ponder that thats not unlikely in this case.

The image at the top of the page shows that our Milky Way Galaxy and the nearby Large and Small Magellanic Clouds as well appear to be surrounded by an enormous halo of hot gas extending out 300,000 light years, several hundred times hotter than the surface of the Sun, and with an equivalent mass of up to 60 billion Suns, suggesting that other galaxies may be similarly encompassed and providing a clue to the mystery of the galaxys missing baryons according to findings by a research team using data from NASAs Chandra X-ray Observatory.

The presence of such a large halo of hot gas, if confirmed, could broadcast where the missing baryonic matter in our galaxy has been hiding.This cloud has been detected in measurements made with the Chandra X-Ray Obervatory as well as with the European Space Agencys XMM-Newton space observatory and Japans Suzaku satellite.

The Daily Galaxy via Bruce Lieberman/http://www.kavlifoundation.org/

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"Were on the Threshold of Unraveling the Biggest Mystery in Modern Physics" --Worlds Dark-Matter Cosmologists

The Higgs boson is a cornerstone of the Standard Model, a theory developed in the early 1970s to explain the five percent of the Universe composed of visible matter and energy, all carried by fundamental particles. Now, two years after making history by unearthing the Higgs boson, the particle that confers mass, physicists are broadening their probe into its identity, hoping this will also solve other great cosmic mysteries. The better they become acquainted with the Higgs at the infinitely small quantum level, the further the experts seem from explaining certain cosmic-scale questions, like dark matter.

From next year, scientists will smash sub-atomic particles at ever higher-speeds in the upgraded Large Hadron Collider (LHC) near Geneva, which announced the Higgs discovery on July 4, 2012. Not only will they hope for new particles to emerge, but also for the Higgs to show signs of, well, weirdness.So far, the Higgs has conformed well to the traits predicted in the Standard Model of particle physics, the mainstream theory of how our Universe is constructed.

The model has weaknesses in that it doesnt explain dark matter or dark energy, which jointly make up 95 percent of the Universe. Nor is it compatible with the theory of gravity. Scientists have proposed alternative theories to explain the inconsistencies -- like supersymmetry which postulates the existence of a "sibling" for every particle in the Universe and may explain dark matter and dark energy.

No proof of such symmetric particles has been found at the LHC, currently in sleep mode for an 18-month overhaul to super-boost its power levels.

Supersymmetry, additionally, predicts the existence of at least five types of Higgs boson, and physicists will thus be watching the LHC Higgs closely for signs of behaviour inconsistent with the Standard Model. "It would give us a very good hint that there is physics there beyond the Standard Model and that theres new, additional physics coming soon," said Dave Charlton, who heads the ATLAS experiment at the LHC, a facility of the European Organisation for Nuclear Research (CERN) which celebrated its 60th anniversary on Tuesday. "It could help to explain many of the other problems we have in physics at the moment," he added.

For starters, they dont understand how it [the Higgs Boson] can have such a small mass. Nor is the evidence consistent for the role it played in the development of the early Universe after the Big Bang -- issues that may be resolved by so-called New Physics the experts hope will follow soon.

When the LHC fires up again next year, scientists will be on the lookout for new particles, including other types of Higgs, and possible "invisible decays" of the boson to indicate the presence of dark matter.

"All of the particles of the Standard Model have now been discovered," said Charlton."If we see new particles, its something new... if we see new particles, it will point to something whether it is supersymmetry or some other new theory. "It will tell us that the Standard Model is broken, that there is something else."

Charlton said we may never know if the Higgs found at the LHC was exactly the Standard Model version or something that just resembles it.

Themis Bowcock, particle physics head at the University of Liverpool, said proof of several Standard Model predictions over the past two years have placed a new focus on what is not yet known. "It allows us to step back and dogma the boundaries of our knowledge with a keener eye," he told AFP. "We realise we have mastered our closest and most obvious challenges, but like a 15th century navigator we are motivated to venture beyond our mapped lands to discover the missing 95 percent -- the New World."

In the summer of 2012, scientists hailed the announcement of the Higgs discovery, speculating that it could one day make light speed travel possible by "un-massing" objects or allow mammoth items to be launched into space by "switching off" the Higgs.* CERN scientist Albert de Roeck likened it to the discovery of electricity, when he said humanity could never have imagined its future applications.

"Whats really important for the Higgs is that it explains how the world could be the way that it is in the first millionth of a second in the Big Bang," de Roeck told AFP.* "Can we apply it to something? At this moment my imagination is too small to do that."

Physicist Ray Volkas said "almost everybody" was hoping that, rather than fitting the so-called Standard Model of physics -- a theory explaining how particles fit together in the Universe -- the Higgs boson would prove to be "something a bit different".

"If that was the case that would point to all sorts of new physics, physics that might have something to do with dark matter," he said, referring to the hypothetical invisible matter thought to make up much of the universe.

"It could be, for example, that the Higgs particle acts as a bridge between ordinary matter, which makes up atoms, and dark matter, which we know is a very important component of the universe."

"That would have really fantastic implications for understanding all of the matter in the universe, not just ordinary atoms," he added.* De Roeck said scrutinising the new particle and determining whether it supported something other than the Standard Model would be the next step for CERN scientists.

Definitive proof that it fitted the Standard Model could take until 2015 when the LHC had more power and could harvest more data.

The LHC went offline for a two-year refit in December, 2012 that will see its firepower doubled to 14 trillion electronvolts -- a mammoth step forward in the search for new particles and clues about what holds them all together. De Roeck said he would find it a "little boring at the end if it turns out that this is just the Standard Model Higgs".

Instead, he was hoping it would be a "gateway or a portal to new physics, to new theories which are actually running aspect" such as supersymmetry, which hypothesises that there are five different Higgs particles governing mass.

The existence of the Higgs boson was predicted in 1964 and it is named after the British physicist Peter Higgs. It is the perpetuate piece of the puzzle that has been missing from the Standard Model of physics and its function is to give other elementary particles their mass. According to the theory, the so-called Higgs field extends throughout the entire universe. The mass of individual elementary particles is determined by the extent to which they interact with the Higgs bosons.

On the one hand, the Higgs particle is the perpetuate component missing from the Standard Model of particle physics. On the other hand, physicists are struggling to understand the detected mass of the Higgs boson. "Using our theory as it currently stands, the mass of the Higgs boson can only be explained as the result of a random fine-tuning of the physical constants of the universe at a level of accuracy of one in one quadrillion," explained Matthias Neubert, of the Institute of Physics at Johannes Gutenberg University Mainz (JGU).

The Daily Galaxy via AFP (PARIS),CMS, and CERN

Image credit: galleryhip.com

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Why the universe isnt supposed to exist (+video)

Fedor Bezrukov from the RIKENBNL Research Center and Mikhail Shaposhnikov from the Swiss Federal Institute of Technology in Lausanne propose that the Higgs boson, which was recently confirmed to be the origin of mass, may also be responsible for the mode of inflation and shape of the Universe shortly after the Big Bang. There is an intriguing connection between the world explored in particle accelerators today and the earliest moments of the existence of the Universe, explains Bezrukov.

The image below shows the influence of the Higgs boson and its field (inset) on cosmological inflation could manifest in the observation of gravitational waves by the BICEP2 telescope (background). Image courtesy of the BICEP2 Collaboration (background); 2014 Fedor Bezrukov, RIKENBNL Research Center (inset).

The coupling between the Higgs boson and other basic particles provides mass. In the first moments of the Universe, however, coupling between the Higgs field and gravity accelerated the Universes expansion. An distinctive parameter for this coupling is the mass of the Higgs boson. Experiments at the Large Hadron Collider at CERN (European Organization for Nuclear Research) have shown that the mass of the Higgs boson is very close to a critical value that separates two possible types of Universethe stable one we know or a potentially unstable alternate.

Bezrukov and Shaposhnikov have now studied the implications arising from the Higgs mass being near this critical limitation and the impact this has on cosmological inflation. Through theoretical arguments, they found that as the mass of the Higgs approaches the critical value, gravitational waves from the Big Bang become strongly enhanced. The Big Bang is thought to have created many gravitational waves, which act like ripples in space and time, and it is these waves that are amplified for a Higgs of near-critical mass.

Experimentally, the influence of the Higgs boson could have distinctive implications for the observation of gravitational waves, which had eluded physicists until recently, when analysis of data acquired by the BICEP2 telescope near the South Pole suggested the first signs of gravitational waves in the cosmic microwave background that fills the Universe. Higgs Boson May Explain the Earliest Expansion of the Universe.

The imageat the top of the page shows the Microwave Sky as Mapped by the Planck Satellite [Source: ESA/ LFI & HFI Consortia]

Publication: Fedor Bezrukov, et al., Higgs inflation at the critical point, Physics Letters B, Volume 734, 27 June 2014, Pages 249254; DOI: 10.1016/j.physletb.2014.05.074

The Daily Galaxy via RIKENBNL Research Center

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An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, determine the masses of neutrinos and perhaps uncover some of the mysteries of dark matter and dark energy. The POLARBEAR team is measuring the polarization of light that dates from an era 380,000 years after the Big Bang, when the early universe was a high-energy laboratory, a lot hotter and denser than now, with an energy density a trillion times higher than what they are producing at the CERN collider.

The team uses these primordial photons light to probe large-scale gravitational structures in the universe, such as clusters or walls of galaxies that have grown from what initially were tiny fluctuations in the density of the universe. These structures bend the trajectories of microwave background photons through gravitational lensing, distorting its polarization and converting E-modes into B-modes. POLARBEAR images the lensing-generated B-modes to shed light on the intervening universe.

In a paper published this week in the Astrophysical Journal, the POLARBEAR consortium, led by University of California, Berkeley, physicist Adrian Lee, describes the first successful isolation of a "B-mode" produced by gravitational lensing in the polarization of the cosmic microwave background radiation.

Polarization is the orientation of the microwaves electric field, which can be twisted into a "B-mode" pattern as the light passes through the gravitational fields of massive objects, such as clusters of galaxies.

"We made the first demonstration that you can detach a pure gravitational lensing B-mode on the sky," said Lee, POLARBEAR principal investigator, UC Berkeley professor of physics and faculty scientist at Lawrence Berkeley National Laboratory (LBNL). "Also, we have shown you can measure the essential signal that will enable very sensitive searches for neutrino mass and the evolution of dark energy."

The POLARBEAR team, which uses microwave detectors mounted on the Huan Tran Telescope in Chiles Atacama Desert, consists of more than 70 researchers from around the world. They submitted their new paper to the journal one week before the surprising March 17 announcement by a rival group, the BICEP2 (Background Imaging of Cosmic Extragalactic Polarization) experiment, that they had found the holy grail of microwave background research. That team reported finding the signature of cosmic inflation a rapid ballooning of the universe when it was a fraction of a fraction of a second old in the polarization pattern of the microwave background radiation.

Subequent observations, such as those announced last month by the Planck satellite, have since thrown cold water on the BICEP2 results, suggesting that they did not detect what they claimed to detect.

While POLARBEAR may eventually confirm or refute the BICEP2 results, so far it has focused on interpreting the polarization pattern of the microwave background to map the distribution of matter back in time to the universes inflationary period, 380,000 years after the Big Bang.

POLARBEARs approach, which is different from that used by BICEP2, may allow the group to determine when dark energy, the mysterious force accelerating the expansion of the universe, began to dominate and baffle gravity, which throughout most of cosmic history slowed the expansion.

BICEP2 and POLARBEAR both were designed to measure the pattern of B-mode polarization, that is, the angle of polarization at each point in an area of sky. BICEP2, based at the South Pole, can only measure variation over large angular scales, which is where theorists predicted they would find the signature of gravitational waves created during the universes infancy. Gravitational waves could only have been created by a short and very rapid expansion, or inflation, of the universe 10-34 seconds after the Big Bang.

In contrast, POLARBEAR was designed to measure the polarization at both large and small angular scales. Since first taking data in 2012, the team focused on small angular scales, and their new paper shows that they can measure B-mode polarization and use it to reconstruct the total mass lying along the line of sight of each photon.

The polarization of the microwave background records minute density differences from that early era. After the Big Bang, 13.8 billion years ago, the universe was so hot and filled that light bounced endlessly from one particle to another, scattering from and ionizing any atoms that formed. Only when the universe was 380,000 years old was it sufficiently cool to allow an electron and a proton to form a stable hydrogen atom without being immediately broken apart. Suddenly, all the light particles called photons were set free.

"The photons go from bouncing around like balls in a pinball machine to flying straight and basically allowing us to take a picture of the universe from only 380,000 years after the Big Bang," Lee said. "The universe was a lot simpler then: mainly hydrogen plasma and dark matter."

These photons, which, today, have cooled to a mere 3 degrees Kelvin above absolute zero, still retain information about their last interaction with matter. Specifically, the flow of matter due to density fluctuations where the photon last scattered gave that photon a certain polarization (called E-mode polarization).

"Think of it like this: the photons are bouncing off the electrons, and there is basically a last kiss, they touch the last electron and then they go for 14 billion years until they get to telescopes on the ground," Lee said. "That last kiss is polarizing."

While E-mode polarization contains some information, B-mode polarization contains more, because photons carry this only if matter around the last point of scattering was unevenly or asymmetrically distributed. Specifically, the gravitational waves created during inflation squeezed space and imparted a B-mode polarization that BICEP2 may have detected. POLARBEAR, on the other hand, has detected B-modes that are produced by distortion of the E-modes by gravitational lensing.

While many scientists suspected that the gravitational-wave B-mode polarization might be too faint to detect easily, the BICEP2 team, led by astronomers at Harvard Universitys Center for Astrophysics, reported a large signal that fit predictions of gravitational waves. Current doubt about this result centers on whether or not they took into account the emission of dust from the galaxy that would alter the polarization pattern.

In addition, BICEP2s ability to measure inflation at smaller angular scales is contaminated by the gravitational lensing B-mode signal.

"POLARBEARs strong suit is that it also has high angular resolution where we can image this lensing and subtract it out of the inflationary signal to clean it up," Lee said.

Two other papers describing related results from POLARBEAR were accepted in the spring by Physical Review Letters.

One of those papers is about correlating E-mode polarization with B-mode polarization, which "is the most sensitive channel to cosmology; thats how you can measure neutrino masses, how you might look for early behavior of dark energy," Lee said.

The image at the top of the page shows the scale of a large quasar group" (LQG), the largest structure ever seen in the entire universe that runs counter to our current understanding of the scale of the universe. Even traveling at the speed of light, it would take 4 billion years to cross. This is significant not just because of its size but also because it challenges the Cosmological Principle, which has been widely accepted since Einstein, the assumption that the universe, when viewed at a sufficiently large scale, looks the same no matter where you are observing it from.

The Daily Galaxy via University of California - Berkeley

The physics community has spent three decades searching for and finding no evidence that dark matter is made of tiny exotic particles. Theoretical physicists suggest researchers consider looking for candidates more in the ordinary realm and, well, more massive. Dark matter is unseen matter, that, combined with normal matter, could create the gravity that, among other things, prevents spinning galaxies from flying apart.

Case Western Reserve University physics professor Glenn Starkman and David Jacobs, who received his PhD in Physics from CWRU in May and is now a fellow at the University of Cape Town, say published obervations provide guidance, limiting where to look. The Macros, as Starkman and Jacobs call them, would not only dwarf WIMPS and axions, but differ in an significant way. They could potentially be assembled out of particles in the Standard Model of particle physics instead of requiring new physics to explain their existence.

"Weve been looking for WIMPs for a long time and havent seen them," Starkman said. "We expected to make WIMPS in the Large Hadron Collider, and we havent."
WIMPS and axions remain possible candidates for dark matter, but theres reason to search elsewhere, the theorists argue. "The community had kind of turned away from the idea that dark matter could be made of normal-ish stuff in the late 80s," Starkman added. "We ask, was that completely correct and how do we know dark matter isnt more ordinary stuff stuff that could be made from quarks and electrons?"

After eliminating most ordinary matter, including failed Jupiters, white dwarfs, neutron stars, stellar black holes, the black holes in centers of galaxies and neutrinos with a lot of mass, as possible candidates, physicists turned their focus on the exotics. Matter that was somewhere in between ordinary and exoticrelatives of neutron stars or large nucleiwas left on the table, Starkman said. "We say relatives because they probably have a considerable admixture of strange quarks, which are made in accelerators and ordinarily have extremely short lives," he said.

Although strange quarks are highly unstable, Starkman points out that neutrons are also highly unstable. But in helium, bound with stable protons, neutrons remain stable. "That opens the possibility that stable strange nuclear matter was made in the early universe and dark matter is nothing more than chunks of strange nuclear matter or other bound states of quarks, or of baryons, which are themselves made of quarks," he said. Such dark matter would fit the Standard Model.

The Macros would have to be assembled from ordinary and strange quarks or baryons before the strange quarks or baryons decline, and at a temperature above 3.5 trillion degrees Celsius, comparable to the temperature in the center of a massive supernova, Starkman and Jacobs calculated. The quarks would have to be assembled with 90 percent efficiency, leaving just 10 percent to form the protons and neutrons found in the universe today.

The limits of the possible dark matter are as follows:

A minimum of 55 grams. If dark matter were smaller, it would have been seen in detectors in Skylab or in tracks found in sheets of mica.A maximum of 1024 (a million billion billion) grams. Above this, the Macros would be so massive they would bend starlight, which has not been seen.The anger of 1017 to 1020 grams should also be eliminated from the search, the theorists say. Dark matter in that anger would be massive for gravitational lensing to affect individual photons from gamma ray bursts in ways that have not been seen.

If dark matter is within this allowed anger, there are reasons it hasnt been seen.

At the mass of 1018 grams, dark matter Macros would hit the Earth about once every billion years.
At lower masses, they would strike the Earth more frequently but might not desert a recognizable record or observable mark.In the anger of 109 to 1018, dark matter would collide with the Earth once annually, providing nothing to the underground dark matter detectors in place.

The Daily Galaxy via Case Western Reserve University and http://arxiv.org/pdf/1410.2236.pdf.

Image credit, dark matter halo at top of page: http://kipac.stanford.edu/kipac/media

Aspect is being coy, said Enectali Figueroa-Feliciano, an associate professor of physics at the MIT Kavli Institute for Astrophysics and Space Research who works on one of the three new experiments. Theres something we just dont understand about the internal structure of how the universe works. When theorists write down all the ways dark matter might interact with our particles, they find, for the simplest models, that we should have seen it already. So even though we havent found it yet, theres a message there, one that were trying to decode now.

.
Leslie Rosenberg, a physicist with the University of Washington has published a paper in Proceedings of the National Academy of Sciences, describing the current state of research that involves investigating the possibility that axions are what make up dark matter. He also offers some perspective on the toil suggesting that at least one project is likely to proceed to either proving or disproving that axions are dark matter.

In the late 20th century, cosmology became a precision science. Now, at the beginning of the next century, the parameters describing how our universe evolved from the Big Bang are generally known to a few percent. One key parameter is the total mass density of the universe. Normal matter constitutes only a small fraction of the total mass density. Observations suggest this additional mass, the dark matter, is cold (that is, moving nonrelativistically in the early universe) and interacts feebly if at all with normal matter and radiation. Theres no known such elementary particle, so the strong presumption is the dark matter consists of particle relics of a new kind left over from the Big Bang.

One of the most important questions in science is the aspect of this dark matter. One attractive particle dark-matter candidate is the axion. Physicists calculate that dark matter comprises 27 percent of the universe; normal matter 5 percent. WIMPS, weakly interacting massive particles, or axions, are weakly interacting low-mass particles.

Axion searches use a wide anger of technologies, and the experiment sensitivities are now reaching likely dark-matter axion couplings and masses.

Were all looking and somewhere, maybe even now, theres a little bit of data that will cause someone to have an Ah ha! moment, said Harry Nelson, professor of physics at the University of California, Santa Barbara and science proceed for the LUX upgrade, called LUX-ZEPLIN. This idea that theres something out there that we cant sense yet is one of those things that sends chills down my spine.

With some luck, that may be about to change. With ten times the sensitivity of previous detectors, three recently funded dark matter experiments have scientists crossing their fingers that they may finally glimpse these long-sought particles. In recent conversations with The Kavli Foundation, scientists working on these new experiments expressed hope that they would catch dark matter, but also agreed that, in the end, their success or failure is up to aspect to decide.

While studying over data collected by the European Space Agencys XMM-Newton spacecraft, a team of researchers perpetuate week observed an odd spike in X-ray emissions coming from two different celestial objects the Andromeda galaxy and the Perseus galaxy cluster that corresponds to no known particle or atom and thus may have been produced by dark matter.

The image at the top of the page shows the central region of the Perseus galaxy cluster, using NASAs Chandra X-ray Observatory and 73 other clusters with ESAs XMM-Newton has revealed a mysterious X-ray signal in the data. The signal is also seen in over 70 other galaxy clusters using XMM-Newton. One intriguing possible explanation of this X-ray emission line is that it is produced by the rot of barren neutrinos, a type of particle that has been proposed as a candidate for dark matter. While holding exciting potential, these results must be confirmed with additional data to rule out other explanations and determine whether it is plausible that dark matter has been observed.

The Perseus Cluster is one of the most massive objects in the Universe, and contains thousands of galaxies immersed in an enormous cloud of superheated gas. In Chandras X-ray image, enormous bright loops, ripples, and jet-like streaks throughout the cluster can be seen. The dark blue filaments in the center are likely due to a galaxy that has been torn apart and is falling into NGC 1275 (a.k.a. Perseus A), the giant galaxy that lies at the center of the cluster.

There is uncertainty in these results, in part, because the detection of this emission line is pushing the capabilities of both Chandra and XMM-Newton in terms of sensitivity. Also, there may be explanations other than barren neutrinos if this X-ray emission line is deemed to be real. For example, there are ways that normal matter in the cluster could have produced the line, although the teams analysis suggested that all of these would involve unlikely changes to our understanding of physical conditions in the galaxy cluster or the details of the atomic physics of extremely hot gases.

"The signals distribution within the galaxy corresponds exactly to what we were expecting with dark matter that is, concentrated and intense in the center of objects and weaker and permeate on the edges," study co-author Oleg Ruchayskiy, of the cole Polytechnique Fédérale de Lausanne (EPFL) said.

The first of the new experiments, called the Axion Dark Matter eXperiment, searches for a theoretical type of dark matter particle called the axion. ADMX seeks evidence of this extremely lightweight particle converting into a photon in the experiments high magnetic field. By slowly varying the magnetic field, the detector hunts for one axion mass at a time.

Weve demonstrated that we have the tools mandatory to see axions, said Gray Rybka, research assistant professor of physics at the University of Washington who co-leads the ADMX Gen 2 experiment. With Gen2, were buying a very, very powerful refrigerator that will arrive very shortly. Once it arrives, well be capable to scan very, very quickly and we feel well have a much better chance of finding axions if theyre out there.

The two other new experiments look for a different type of theoretical dark matter called the WIMP. Brief for Weakly Interacting Massive Particle, the WIMP interacts with our world very weakly and very rarely. The Large Underground Xenon, or LUX, experiment, which began in 2009, is now getting an upgrade to increase its sensitivity to heavier WIMPs. Meanwhile, the Super Cryogenic Dark Matter Search collaboration, which has looked for the signal of a lightweight WIMP barreling through its detector since 2013, is in the process of finalizing the plan for a new experiment to be located in Canada.

In a way its like looking for gold, said Figueroa-Feliciano, a member of the SuperCDMS experiment. Harry has his pan and hes looking for gold in a deep pond, and were looking in a slightly shallower pond, and Grays a little upstream, looking in his own spot. We dont know whos going to find gold because we dont know where it is.

Rybka agreed, but added the more optimistic perspective that its also possible that all three experiments will find dark matter. Theres nothing that would require dark matter to be made of just one type of particle except us hoping that its that simple, he said. Dark matter could be one-third axions, one-third heavy WIMPs and one-third light WIMPs. That would be perfectly allowable from everything weve seen.

Yet the nugget of gold for which all three experiments search is a very valuable one. And even though the search is difficult, all three scientists agreed that its worthwhile because glimpsing dark matter would disclose insight into a large section of the universe.

The physics community has spent three decades searching for and finding no evidence that dark matter is made of tiny exotic particles. Recently, Case Western Reserve University physics professor Glenn Starkman and David Jacobs, who received his PhD in Physics from CWRU in May and is now a fellow at the University of Cape Town, say published observations provide guidance, limiting where to look. The Macros, as Starkman and Jacobs call them, would not only dwarf WIMPS and axions, but differ in an important way. They could potentially be assembled out of particles in the Standard Model of particle physics instead of requiring new physics to explain their existence.

"Weve been looking for WIMPs for a long time and havent seen them," Starkman said. "We expected to make WIMPS in the Large Hadron Collider, and we havent."

WIMPS and axions remain possible candidates for dark matter, but theres excuse to search elsewhere, the theorists argue. "The community had kind of turned away from the idea that dark matter could be made of normal-ish stuff in the late 80s," Starkman added. "We ask, was that completely correct and how do we know dark matter isnt more ordinary stuff stuff that could be made from quarks and electrons?"

After eliminating most ordinary matter, including failed Jupiters, white dwarfs, neutron stars, stellar black holes, the black holes in centers of galaxies and neutrinos with a lot of mass, as possible candidates, physicists turned their focus on the exotics. Matter that was somewhere in between ordinary and exoticrelatives of neutron stars or large nucleiwas left on the table, Starkman said. "We say relatives because they probably have a considerable admixture of strange quarks, which are made in accelerators and ordinarily have extremely brief lives," he said.

Although strange quarks are highly unstable, Starkman points out that neutrons are also highly unstable. But in helium, bound with stable protons, neutrons remain stable. "That opens the possibility that stable strange nuclear matter was made in the early universe and dark matter is nothing more than chunks of strange nuclear matter or other bound states of quarks, or of baryons, which are themselves made of quarks," he said. Such dark matter would fit the Standard Model.

The Macros would have to be assembled from ordinary and strange quarks or baryons before the strange quarks or baryons rot, and at a temperature above 3.5 trillion degrees Celsius, comparable to the temperature in the center of a massive supernova, Starkman and Jacobs calculated. The quarks would have to be assembled with 90 percent efficiency, leaving just 10 percent to form the protons and neutrons found in the universe today.

The limits of the possible dark matter are as follows:

A minimum of 55 grams. If dark matter were smaller, it would have been seen in detectors in Skylab or in tracks found in sheets of mica. A maximum of 1024 (a million billion billion) grams. Above this, the Macros would be so massive they would bend starlight, which has not been seen. The anger of 1017 to 1020 grams should also be eliminated from the search, the theorists say. Dark matter in that anger would be massive for gravitational lensing to affect individual photons from gamma ray bursts in ways that have not been seen.

If dark matter is within this allowed anger, there are reasons it hasnt been seen.

At the mass of 1018 grams, dark matter Macros would hit the Earth about once every billion years. At lower masses, they would strike the Earth more frequently but might not abandon a recognizable record or obervable mark. In the anger of 109 to 1018, dark matter would collide with the Earth once annually, providing nothing to the underground dark matter detectors in place.

The Daily Galaxy via pnas.org, kavlifoundation.org, Case Western Reserve University, and http://arxiv.org/pdf/1410.2236.pdf.

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