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Prime candidate crossed off list in search for dark matter particle

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May 14, 2014

HADES at the GSI in Darmstadt/Germany searches for dark matter candidates (Image: A. Schma...

HADES at the GSI in Darmstadt/Germany searches for dark matter candidates (Image: A. Schmah/HADES)

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Dresden, Germany have analyzed data from the HADES particle detector and concluded that the so-called "dark photons" are not the constituents of dark matter. Dark photons, or U bosons, are hypothetical particles that had thus far been the main candidate for that role, and this new result could make the search for the dark matter particle even more challenging than before.

According to the latest observations, about 70 percent of the mass-energy in our universe is made out of dark energy, about 25 percent is made out of dark matter, and only the remaining roughly 5 percent is made out of the ordinary, baryonic matter that we are most familiar with.

We know that dark matter clumps together under the force of gravity, affecting the way light bends around visible matter. However, it does not emit or reflect enough electromagnetic radiation to be observed directly, which makes it very hard to study. Physicists have long been looking for the particle that makes up dark matter, but so far they've been disappointed. Researchers have now come to believe that dark matter is comprised by unknown particles which do not fit into the Standard Model of particle physics.

One of the most promising candidates was a hypothetical particle named a "U boson," or "dark photon." The particle owes its nickname to the fact that it would have characteristics similar to photons, but with a mass, meaning it would have a weak interaction with standard, baryonic matter (photons are considered to be massless; if they weren't, they wouldn't be able to move at the speed of light in the vacuum).

But now, researchers at HZDR have concluded that these dark photons cannot be the particle that physicists were looking for. To come to that conclusion, the scientists analyzed data from the High-Acceptance Di-Electron Spectrometer (HADES) detector, collided over ten billion protons and atomic nuclei, collecting information on the resulting debris. The results exclude the possibility that these are the particle that they had been looking for.

In light of the new information, the search for the dark matter particle becomes even more challenging. For the time being, scientists have only found negative results excluding possible candidates, but no positive hint to help them better direct their search.

The research was published on the journal Physical Letters B.

Source: HZDR

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion.   All articles by Dario Borghino
6 Comments

Maybe there is a problem with the whole Big Bang theory of cosmology and what really happened does not need dark matter or dark energy to make the universe work.

Slowburn
15th May, 2014 @ 11:38 am PDT

I would agree.

I am working on a theory which is not done yet.

What do you think of this?

Black hole

high temperature and energy

the laws of physics we are used to do not apply

event horizon as even light can not escape only Hawking radiation.

It sucks matter in and we do not know where it goes.

Big Bang

high temperature and energy

the laws of physics we are used to do not apply

event horizon as nothing can be measured before it

The whole universe comes out of very little or nothing

are these connected?

Black hole one side

Big Bang other side

of the same thing?

So we have a black hole at the center of every galaxy

a Big Bang on the other side of every galaxy?

Buzz Allnight
15th May, 2014 @ 08:04 pm PDT

An emergent understanding of galaxy cluster, galaxy and star formation from a baryonic dark matter hypothesis.

Cherchez la phase change reaction.

In the early years of the Universe following the "Dark Ages", galaxy-cluster-sized aggregations (GCSAs) of primordial hydrogen (75%) and helium (25%) with trace deuterium and lithium held together by gravity against internal gas pressure may have reionized the Universe due to compressive heating, but hydrogen plasma nucleation in GCSAs occurred at billions or trillions of sites like water droplets in terrestrial clouds. Hydrogen ionization promoted localized gravitational densification due to endothermic temperature clamping, forming discrete gas globules.

As the ambient temperature in the Universe cooled, gas pressure could no longer support GCSAs so they contracted gravitationally until angular momentum halted the contraction. Bulk angular momentum vectors of ionized globules gave rise to super-powerful GCSA magnetic fields that repelled one another to the extent of their misalignment, in our case magnetically repelling Andromeda from the Milky Way.

As galaxies deflated with decreasing ambient temperature, high angular momentum clumps formed dwarf satellite galaxies while near zero angular-momentum globules fell to the center to form the central bulge (and the super-massive black hole).

Large globules (100-300 solar masses?) spontaneously collapsed to form Population III stars and Wolf-Rayet stellar winds ejected heavier elements into the interstellar medium, providing the material for Population I stars while Population III stars quickly collapsed into black holes and degenerate stars. Smaller globules that survived spontaneous collapse cooled over the next 13-1/2 billion years to become the coldest objects in the Universe.

A significant percentage of globules with formerly low inclinations were tidally drawn into the spiral-arm accretion disk around the central bulge of the Milky Way where some evaporated a majority of their hydrogen to become volatile-depleted (while absorbing dust, carbon monoxide & etc.), and thus apparently helium (and deuterium) enriched. The elevated helium globules that gravitationally collapsed formed (extreme) helium stars. Small groups of the few remaining globules and outgassing 'cometary globules' in the spiral arms form the (giant) molecular clouds of today. Gravitational collapse of Bok globules into OB supergiants may be caused mutual collisions, supernova shock-wave pressurization and etc. with T-Tauri stars condensing around their periphery.

Eighty percent or so of the remaining baryonic matter in the Milky Way is locked up in primordial Bok globule dark matter in the halo and the central bulge which are nearly primordial in composition (almost dust and carbon-monoxide free) and therefore nearly invisible to electromagnetic radiation and heretofore undetected. And early ionized intergalactic Bok globules stranded between magnetically-repulsed galaxies aligned themselves along intergalactic magnetic field lines, forming intergalactic dark-matter filaments.

Bok globules = dark matter

David Carlson
16th May, 2014 @ 12:14 pm PDT

"Physicists have long been looking for the particle that makes up dark matter, but so far they've been disappointed."

Personally I'm waiting for the physics world to realize that Dark Matter is the modern Aether. Where are the modern Michelson and Morley when we need them?

Russell Poley
17th May, 2014 @ 06:37 pm PDT

"Personally I'm waiting for the physics world to realize that Dark Matter is the modern Aether. Where are the modern Michelson and Morley when we need them?"

Why would you say that? It seems to be the opposite case. The ether was postulated but not observed. Michelson and Morley attempted to measure a property of the ether and their null result showed that it didn't exist.

Dark matter was not postulated. The observation of its existence was a surprise. Thus, we know it exists but can't explain it.

neutrino23
19th May, 2014 @ 12:46 am PDT

>Why would you say that? It seems to be the opposite case. The ether was postulated but not observed. Michelson and Morley attempted to measure a property of the ether and their null result showed that it didn't exist.

Actually faults were found with M&M's experiment. New ones were made, more faults found, etc. It actually wasn't until the 1970's that an experiment was performed that addressed all of the criticisms and it obtained a small *positive* result. However, by this time everyone had already decided there was no ether, so the results were ignored and there certainly wasn't funding forthcoming to attempt to replicate.

>Dark matter was not postulated. The observation of its existence was a

>surprise. Thus, we know it exists but can't explain it.

This is incorrect. Observations were made that contradicted the Big Bang model. Science assumed that the Big Bang model must be correct and thus postulated Dark Matter to explain the observations. "Dark matter" is just a set of properties designed to explain another observation. Since no one knows what dark matter would be, it has never been observed. What's been observed are the otherwise unexplained effects of mass in places where we do not see mass.

Alternative theories such as Modified Newtonian Dynamics (MOND) can explain the observations with an adjustment to the law of gravity without needing any dark matter. Plasma cosmology also makes claim to explain some of these observations via electromagnetic forces rather than via a new type of matter.

alcalde
26th May, 2014 @ 04:14 pm PDT
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