Periodicity AGAIN?!?! Dark Matter 'Caused' Mass Extinctions?

Mass Extinctions and a Dark Disk

Authors:

Kramer et al

Abstract:

We consider whether the observed periodicity of mass extinctions and of comet impacts on Earth is consistent with Solar oscillation about the Galactic midplane and spiral arm crossings. It is of further interest to determine whether a hypothetical thin dark disk is necessary to give the right periodicity, and whether such a dark disk is allowed given kinematic and other observational constaints on the Galaxy's gravitational potential. We show that a dark disk consistent with recent bounds, combined with data for spiral arm crossing, can lead to the required periodicity. Moreover, we find that the best fit values correctly predict the date of the Chicxulub crater dated to 66 My ago.

Could Primordial Black Holes be Dark Matter

Primordial Black Holes as Dark Matter

Authors:

Carr et al

Abstract:

The possibility that the dark matter comprises primordial black holes (PBHs) is considered, with particular emphasis on the currently allowed mass windows at 1016 -- 1017g, 1020 -- 1024g and 1 -- 103M⊙. The Planck mass relics of smaller evaporating PBHs are also considered. All relevant constraints (lensing, dynamical, large-scale structure and accretion) are reviewed and various effects necessary for a precise calculation of the PBH abundance (non-Gaussianity, non-sphericity, critical collapse and merging) are accounted for. It is difficult to put all the dark matter in PBHs if their mass function is monochromatic but this is still possible if the mass function is extended, as expected in many scenarios. A novel procedure for confronting observational constraints with an extended PBH mass spectrum is therefore introduced. This applies for arbitrary constraints and a wide range of PBH formation models, and allows us to identify which model-independent conclusions can be drawn from constraints over all mass ranges. We focus particularly on PBHs generated by inflation, pointing out which effects in the formation process influence the mapping from the inflationary power spectrum to the PBH mass function. We then apply our scheme to two specific inflationary models in which PBHs provide the dark matter. The possibility that the dark matter is in intermediate-mass PBHs of 1 -- 103M⊙ is of special interest in view of the recent detection of black-hole mergers by LIGO. The possibility of Planck relics is also intriguing but virtually untestable.

Are Planets Ensnared in Dark Matter Strands?

DENSE DARK MATTER HAIRS SPREADING OUT FROM EARTH, JUPITER, AND OTHER COMPACT BODIES

Author:

Prézeau

Abstract:

It is shown that compact bodies project out strands of concentrated dark matter filaments, henceforth simply called hairs. These hairs are a consequence of the fine-grained stream structure of dark matter halos, and as such constitute a new physical prediction of ΛCDM. Using both an analytical model of planetary density and numerical simulations utilizing the Fast Accurate Integrand Renormalization algorithm (a fast geodesics calculator described below) with realistic planetary density inputs, dark matter streams moving through a compact body are shown to produce hugely magnified dark matter densities along the stream velocity axis passing through the center of the body. Typical hair density enhancements are 10⁷ for Earth and 10⁸ for Jupiter. The largest enhancements occur for particles streaming through the core of the body that are mostly focused at a single point called the root of the hair. For the Earth, the root is located at about 10⁶ km from the planetary center with a density enhancement of around 10⁹ while for a gas giant like Jupiter, the root is located at around 10⁵ km with an enhancement of around 10¹¹. Beyond the root, the hair density precisely reflects the density layers of the body, providing a direct probe of planetary interiors.

Extraordinary Claim: How to Detect Dark Matter...From the Earth's Core

Dark Photons from the Center of the Earth: Smoking-Gun Signals of Dark Matter

Authors:

Feng et al

Abstract:

Dark matter may be charged under dark electromagnetism with a dark photon that kinetically mixes with the Standard Model photon. In this framework, dark matter will collect at the center of the Earth and annihilate into dark photons, which may reach the surface of the Earth and decay into observable particles. We determine the resulting signal rates, including Sommerfeld enhancements, which play an important role in bringing the Earth's dark matter population to their maximal, equilibrium value. For dark matter masses mX∼ 100 GeV - 10 TeV, dark photon masses mA′∼ MeV - GeV, and kinetic mixing parameters ε∼10−9−10−7, the resulting electrons, muons, photons, and hadrons that point back to the center of the Earth are a smoking-gun signal of dark matter that may be detected by a variety of experiments, including neutrino telescopes, such as IceCube, and space-based cosmic ray detectors, such as Fermi-LAT and AMS. We determine the signal rates and characteristics, and show that large and striking signals---such as parallel muon tracks---are possible in regions of the (mA′,ε) plane that are not probed by direct detection, accelerator experiments, or astrophysical observations.

I Hate Self Referencing, but! Worlds Made of Dark Matter Theorized

img src here.

However, the image is NOT mine, but rather a cool picture to add some visual for this.   There are no, theorized, worlds made of neutron- and white dwarf star stuff and...dark matter.  Take a look.

SETI Institute Talks: Dark Matter & WIMPs

YAGUMET STRIKE AGAIN! Dark Matter Did it! Blame DM for Mass Extinctions! Periodicity Returns!

Disc dark matter in the Galaxy and potential cycles of extraterrestrial impacts, mass extinctions and geological events

Author:

Rampino

Abstract:

A cycle in the range of 26–30 Myr has been reported in mass extinctions, and terrestrial impact cratering may exhibit a similar cycle of 31 ± 5 Myr. These cycles have been attributed to the Sun's vertical oscillations through the Galactic disc, estimated to take from ∼30 to 42 Myr between Galactic plane crossings. Near the Galactic mid-plane, the Solar system's Oort Cloud comets could be perturbed by Galactic tidal forces, and possibly a thin dark matter (DM) disc, which might produce periodic comet showers and extinctions on the Earth. Passage of the Earth through especially dense clumps of DM, composed of Weakly Interacting Massive Particles (WIMPs) in the Galactic plane, could also lead to heating in the core of the planet through capture and subsequent annihilation of DM particles. This new source of periodic heating in the Earth's interior might explain a similar ∼30 Myr periodicity observed in terrestrial geologic activity, which may also be involved in extinctions. These results suggest that cycles of geological and biological evolution on the Earth may be partly controlled by the rhythms of Galactic dynamics.

Again, YAGUMET.

China Majorly Upgrading China Jinping Underground Laboratory

For certain physics experiments, deeper is better. Since it opened in 2010, the China Jinping Underground Laboratory (CJPL)—in a hollowed-out cavern along a tunnel in Sichuan province—has been the world's deepest underground laboratory. Two thousand four hundred meters of rock have shielded its experimental chambers from background radiation that might mask the extremely subtle traces of dark matter, the universe's postulated missing mass. CJPL's observational capabilities were limited by its mere 4000-cubic-meter size. It is about to grow to 120,000 cubic meters, making it the world's second largest underground lab and positioning it to make breakthrough contributions to fundamental investigations into dark matter, neutrinos, and conditions in the early universe.

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Could a 35 Year old Stanford Linear Accelerator Experiment Give Clues to Dark Matter?

Here’s one reason libraries hang on to old science journals: A paper from an experiment conducted 32 years ago may shed light on the nature of dark matter, the mysterious stuff whose gravity appears to keep the galaxies from flying apart. The old data put a crimp in the newfangled concept of a "dark photon" and suggest that a simple bargain-basement experiment could put the idea to the test.

No one really knows what dark matter is. Since the 1980s, theorists' best hunch has been that it consists of so-called weakly interacting massive particles, or WIMPs. If they exist, WIMPs would have a mass between one and 1000 times that of a proton. They would interact only through the feeble weak nuclear force—one of two forces of nature that ordinarily flex their muscle only within the atomic nucleus—and could disappear only by colliding and annihilating one another. So if the infant universe cooked up lots of WIMPs, enough of them would naturally survive to produce the right amount of dark matter today. But physicists have yet to spot WIMPs, which every now and then should ping off atomic nuclei in sensitive detectors and send them flying.

More recently, theorists have explored other ideas, such as self-interacting dark matter. This would consist of a particle, known as a χ (pronounced chi), with a mass between 1/1000 and one times that of the proton. Those particles would interact with one another through a force like the electromagnetic force, which produces light. That force would be conveyed by a massive particle called a dark photon—a dark matter version of a particle of light—that might "mix" slightly with the ordinary ones. So with some small probability, a dark photon might interact with ordinary charged particles such as electrons and atomic nuclei—just as ordinary photons do.

Self-interacting dark matter has attractive properties. In particular, a dark photon could also explain a particle physics puzzle. A particle called the muon appears to be very slightly more magnetic than theory predicts, and that discrepancy could be resolved if the muon interacts with dark photons lurking in the vacuum. However, χs and dark photons would be hard to detect with WIMP detectors; with their low masses, they couldn't whack a nucleus hard enough to create a signal.

But archival data already rule out dark photons with certain combinations of properties, argues Rouven Essig, a theoretical physicist at Stony Brook University in New York, and his colleagues. The data come from E137, a "beam dump" experiment that ran from 1980 to 1982 at SLAC National Accelerator Laboratory in Menlo Park, California. In the experiment, physicists slammed a beam of high-energy electrons, left over from other experiments, into an aluminum target to see what would come out. Researchers placed a detector 383 meters behind the target, on the other side of a sandstone hill 179 meters thick that blocked any ordinary particles. They then looked for hypothetical particles called axions, which would have pierced the earth and reached the detector—and saw none.

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China's PandaX Facility is Looking for Dark Matter

The new PandaX facility, located deep underground in the southwestern Chinese province of Sichuan, hosts a large liquid-xenon detector designed to search for direct evidence of dark matter interactions with the nuclei of xenon and to observe 136Xe double-beta decay.

The detector's central vessel was designed to accommodate a staged target volume increase from an initial 120 kg (stage I) to 0.5 t (stage II) and ultimately to a multi-ton scale.

The technical design of the PandaX facility and detector is outlined in a new paper co-authored by Ji Xiangdong, of the Institute of Nuclear and Particle Physics, Astronomy and Cosmology at Shanghai Jiao Tong University, and published in the Beijing-based journal SCIENCE CHINA Physics, Mechanics & Astronomy.

While noting that cosmologists generally agree that 80 percent of the matter in the universe is made up of some form of "dark matter," these researchers also acknowledge that so far, no physicist has ever produced experimental data that provides convincing evidence for the existence and structure of dark matter.

"The standard model of particle physics, which has been very successful in explaining the properties of ordinary matter, can neither explain dark matter's existence nor its properties," Professor Ji and co-authors across China and the United States write in the new study. "Yet the discovery and identification of dark matter would have a profound impact on cosmology, astronomy, and particle physics."

"A leading dark matter candidate consistent with all astrophysical data is a weakly interacting massive particle (WIMP)," they add. "WIMPs could be studied in standard particle physics through either observations of ordinary matter particles produced through DM [dark matter] annihilations in the halo of the Milky Way, production of DM particles through high-energy collisions in accelerators such as the Large Hadron Collider, or WIMPs could be detected through their interactions with atomic nuclei in specially designed detectors."

Direct detection experiments are deployed in underground laboratories around the world. When WIMPs interact with nucleons in a detection medium, it is predicted they will recoil and generate kinetic motion of atoms (heat), ionization (free electrons) and scintillation (de-excitation of excited electrons).

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DOE & NSF Both Fund Dark Matter Experiments

For a change, U.S. particle physicists are savoring some good news about government funding. The Department of Energy (DOE) and the National Science Foundation (NSF) announced on Friday that they will try to fund two major experiments to detect particles of the mysterious dark matter whose gravity binds the galaxies instead of just one. The decision allays fears that the funding agencies could afford only one experiment to continue the search for so-called weakly interacting massive particles, or WIMPs. It also averts having to choose between the two leading WIMP-search teams in the United States.

"We have the opportunity right now for the U.S. experiments to push further in sensitivity and possibly make a discovery," says Richard Gaitskell, a physicist at Brown University and a member of the team developing a WIMP detector called LZ, one of the two leading projects. "There's a real commitment from the community and the funding agencies." Blas Cabrera, a physicist at Stanford University in Palo Alto, California, and spokesman for the rival SuperCDMS experiment, says that having to pick only one team “would have been a grave mistake."

For decades, astronomers and astrophysicists have reasoned that some sort of otherwise unobservable dark matter provides most of the gravity that keeps the galaxies from flying apart. Physicists hope to identify that stuff by detecting particles of it floating around us. For example, dark matter could consist of WIMPs, hypothetical particles that would barely interact with ordinary matter and weigh much more than protons.

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