Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Dilaton could affect abundance of dark matter particles

The amount of dark matter left over from the early universe may be less than previously believed. Research published in the open access journal PMC Physics A shows that the "relic abundance" of stable dark matter particles such as the neutralino may be reduced as compared to standard cosmology theories due to the effects of the "dilaton"', a particle with zero spin in the gravitational sector of strings.

Nikolaos Mavromatos of King's College London and colleagues in Athens and Texas obtained their result by studying a special "off-shell" time-dependent term (due to the dilaton) in the Boltzmann equation that describes the evolution of hot matter density as the Universe cooled down. "The formalism that this work used was developed in partial collaboration with John Ellis of CERN and Vasiliki Mitsou of IFIC, Valencia, and is a version of 'non-critical string theory'", said Mavromatos.

All the matter and radiation in the universe is thought to have been created by the Big Bang. The radiation stopped interacting with the matter some 400,000 years later -- when the universe had cooled down enough for electrons and protons to form hydrogen atoms. The density of dark matter particles such as the neutralino (a dark matter candidate favoured by many of the current "supersymmetric" approaches to particle physics) was therefore "frozen" at this time -- the so-called relic abundance.

The researchers say that the neutralino relic abundance is reduced by as much as a factor of ten in their models due to dilaton effects, as compared to standard cosmology theories. In contrast, the relic abundance of "ordinary" matter, which makes up stars, planets and humans, is only slightly diluted. The new model also agrees with the established model of nucleosynthesis (the way in which light elements were created during the first few minutes of the universe).

The new result is important for both cosmology and particle physics, says Mavromatos. Indeed, such non-equilibrium string cosmology models are on an equal footing with the standard cosmological cold dark matter model (called Lambda-CDM). For particle physics, the findings are relevant for future supersymmetric searches in colliders such as the Large Hadron Collider, due to come on-line at CERN early next year. The supersymmetric theory, one of the facets of string theory, postulates that every particle has a massive "shadow" particle partner.

Dark matter is fundamentally different from normal, luminous matter and is invisible to modern telescopes, giving off no light or heat. It appears to interact with normal matter only through gravity. Most cosmologists believe dark matter, currently thought to make up 95% of all matter in the universe, plays a crucial role in how large structures such as galaxies emerged after the Big Bang.

Charlotte Webber | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>