Cosmologists are agog about the possibility that an orbiting
observatory may have discovered particles of dark matter — the proposed,
invisible material that researchers believe makes up most of the mass of the universe.
At two meetings in August, researchers analyzing data from
the Russian-European observatory PAMELA, short for Payload for Antimatter
Matter Exploration and Light-nuclei Astrophysics, reported preliminary evidence
that the device had recorded more positrons from the Milky Way than could be
accounted for by the standard model of elementary particle physics.
At the International Conference on High Energy Physics, held
in Philadelphia, PAMELA researcher Mirko Boezio of the Italian National
Institute of Nuclear Physics in Trieste suggested that the surplus of positrons
— the electron’s antiparticle, which is equal in mass but opposite in charge —
could be accounted for by the annihilation of pairs of dark-matter particles.
According to an existing theory, when dark-matter particles collide, they decay
into a spray of ordinary, visible particles, including an abundance of
positrons.
“We plan to have final results ready by early October and
submit a paper to a peer-reviewed journal,” Boezio told Science News. Until then, he says, the findings remain preliminary,
and “We prefer to withhold further comments.”
But that hasn’t stopped other researchers from posting their
interpretations of the data on the Internet.
In a paper posted August 28, Marco Cirelli of the Institute
of Physical Theory at the French Atomic Energy Commission near Paris and
Alessandro Strumia of the University of Pisa and the Italian nuclear physics
institute report that the PAMELA findings appear to be consistent with the
existence of a proposed dark-matter particle known as minimal dark matter (http://arxiv.org/abs/0808.3867).
Their minimal model would introduce a set of five new
elementary particles that interact only through a weak nuclear force. The
theory suggests that a dark-matter particle is about 10,000 times heavier than a
proton.
The model “adds to the standard model of particle physics
the minimal amount of new ingredients that allows [researchers] to explain the
existence and the properties of dark matter without ruining the good features
of the standard model,” Cirelli and Strumia wrote in an e-mail message.
Astronomers have proposed the existence of dark matter for
decades because it would provide the unseen glue that keeps galaxies intact and
galaxy clusters from disassembling. However, dark matter has never been
convincingly detected.
Although the preliminary PAMELA data are intriguing, the
researchers caution that “There might still be adjustments or calibrations that
will change the data, and this is only in the hands of the PAMELA
collaboration.” Astronomers must also make sure that ordinary astrophysical
objects that produce positrons, such as supernovas, are not responsible for the
excess particles.
One promising feature of the PAMELA data, Cirelli and
Strumia say, is that the observatory appears to have recorded an abrupt rise in
positrons with energies of about 10 billion electronvolts. That rise is just
what the annihilation of dark-matter particles predicts. In contrast, known astrophysical
processes would produce a more gradual increase in positrons.
The upturn “is a classic signature of new physics,” says
Vernon Barger of the University of Wisconsin–Madison. He and his collaborators
calculate that the annihilation of cold dark-matter particles can explain the
excess of positrons detected by the observatory (http://arxiv.org/abs/0809.0162). Cold
dark-matter particles move slowly compared with the speed of light and are most
widely used in cosmological theories, much more so than minimal dark matter
particles.
In another recently posted paper, University of Stockholm
researchers Lars Bergström, Torsten Bringmann and Joakim Edsjö suggest that
PAMELA may have detected a type of dark matter predicted by supersymmetry, a
proposed extension of the standard particle physics model that would double the
number of known elementary particles (http://arxiv.org/abs/0808.3725).
The lightest of these supersymmetric particles, which would have been forged
immediately after the Big Bang, would be stable and could exist today, the
researchers note. Moreover, a small
fraction of these proposed dark-matter particles would encounter each other in
space. Such meetings would end in destruction because each of these particles
acts as its own antiparticle. And when the particles annihilate, they produce
an assortment of ordinary particles, including positrons.
But Bergström and Bringmann caution that any model that
invokes dark matter to account for the positron excess still requires fine-tuning
to match the PAMELA data. For instance, their own model requires a
thousand-fold boost in the predicted rate that dark-matter particles in the
Milky Way, on average, would annihilate. This increase could be achieved if
some parts of the galaxy harbor unusually dense clumps of dark matter, they
suggest.
Found in: Atom & Cosmos
Text Size
The fact that baryonic matter seems to make up only 1/5 to 1/6 of the mass-energy content of our universe wherein the total of this material based mass-energy is only about 28 percent of the total energy content of our universe (the remaining 72 percent existing in the form of the yet more mysterious Dark Energy), begs the question as to whether the particulate form of mattergy is composed of roughly 28/5 or 28/6 types of dark matter since such a particle class distribution would display a certain evenness in the distribution of dark matter verses such would be particle classes in terms of class relative total mattergy content of the particulate matter.
Note that the ratio of 28%/5 and 28%/6 is roughly 4.6% which is the amount of baryonic matter contained within the universe according to the experimental/observational results of the WMAP Probe.
An alternative way to consider the observational findings is to form the ratios 72/23 and 23/4.6 which are roughly on the same order of magnitude. The values of 100/23 and 28/4.6 are also of roughly the same order of magnitude to each other perhaps suggesting that there is only one fundamental type or class of dark matter particle. The reasoning behind this conjecture, in the first case, by symmetry is the consideration of the rough equality of the ratio of the percentage of the total universe energy in the form of dark energy (72%)and that of the particulate dark mattergy(23%) and the ratio of the percentage of dark matter (23%)and that of baryonic or visible matter(4.6%). In the second case, the argument by symmetry is the rough equality of the ratio of the total energy content of the universe (100%) and that of the dark particulate mattergy content (23%)to the ratio of the total particulate mattergy content of the observable universe (28%) to that of the baryonic or visible matter content (4.6%) of the universe.
Note also that the ratios of 100/23 and 23/4.6 are also close in value to each other.
The value 100/28 is roughly one half that of 28/4.6 thus perhaps suggesting the existence two classes of cold dark matter particles, because of the close matching of the relative size of these two values with the relative size of the two terms in the series 1/n and 2/n respectively. One might even argue that there is some fundamental reason why the relative values of 100/28 and 28/4.6 are close to that of 1/n and 2/n. Nature for some obscure or fundamental reason may have chosen this relationship and/or the relationships between the ratios discussed in the previous paragraph for some fundamental reason.
Thus, there may be some relatively simple but obscure and fundamental relationship between the relative abundance of the forms of mattergy within our universe. The dark energy content, dark matter content, visible baryonic matte content and the total particulate mattergy content of our universe may be related in an existential or casual manner through some sort of casual coupling mechanism.
As the matter and antimatter annihilated each other, 4% of the original matter remained.
It is interesting to note, that 4% is also the amount of matter now speculated to exist, compared to the contemplated dark matter and dark energy.
It occurred to me, that in the mutual annihilation of matter and antimatter the 96% that was destroyed, was transformed into a huge number of small black holes. These well distributed black holes in effect simulating, what lately has been described as dark matter.
Dark energy, could be the Hawking radiation released from the tremendous surface areas of all these black holes.
The cosmological constant, the acceleration of the expansion of the Universe, its relatively flat shape, the differences between real and calculated distances of far-reaching exploring man-made satellites, all point to two realities.
One is that our linear progression of numbers may not reflect the reality of the very small and very large words. But this is trivial.
The other one is that dark matter is the remnant of matter existing before the Big Bang. Imagine it as a cloud-like atmosphere. Any new matter created by the Big Bang inside this cloud will have to fight against the resistance of the cloud, up to the time when this matter will reach the limits of the cloud . Then it will travel into a less dense cloud or nothing such increasing its speed. The dark matter, under some conditions to be defined, would have been able to create the Big Bang.
My point is that dark matter and dark energy preceded and created the Big Bang. It also explains the expansion of the Universe and its future. Now, what was before Dark matter has still to be investigated. I count on results of the CERN experiments to give me clues.
This idea has to be explored by better minds that mine. I am just using the power of logics.
Thank you for your attention,
Regards,
John Besse-Lascours
Please login or register to participate.