Anti matter

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Fossaw
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Anti matter

Post by Fossaw » Thu Jun 30, 2016 11:31 am

I was watching an old lecture at Gresham College when an old conceptual area I had heard numerous times before arose. That there was a "slight preponderance" of matter over anti matter in the early universe. I fail to see why that should be. I can see that things here are composed of matter, that other things in the solar system so far investigated are matter, that possibly the entire galaxy or galactic group is matter. How can one tell that, for example, the Coma Cluster is not comprised entirely of antimatter? A star fusing anti protons to form anti Helium emits what, anti energy, I doubt it. Then again, we hear all the time of dark matter and dark energy.

>>> edit <<<
Spelling correction.

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neufer
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Re: Anti matter

Post by neufer » Thu Jun 30, 2016 1:32 pm

Fossaw wrote:
How can one tell that, for example, the Coma Cluster is not comprised entirely of antimatter? A star fusing anti protons to form anti Helium emits what, anti energy, I doubt it.>>
  • Why would matter & antimatter separate on such scales (and so cleanly)?

    Where are the "fireworks" at the boundaries of these outliers.

    Where are the antihelium cosmic rays?
https://en.wikipedia.org/wiki/Antimatter#Observation_in_cosmic_rays wrote:
<<There is no evidence of complex antimatter atomic nuclei, such as antihelium nuclei (i.e., anti-alpha particles), in cosmic rays. These are actively being searched for.>>
Fossaw wrote:
Then again, we hear all the time of dark matter and dark energy.>>
  • Perhaps Fritz Zwicky found dark antimatter in the Coma Cluster:
https://en.wikipedia.org/wiki/Coma_Cluster wrote:
<<The Coma Cluster is one of the first places where observed gravitational anomalies were considered to be indicative of unobserved mass. In 1933 Fritz Zwicky showed that the galaxies of the Coma Cluster were moving too fast for the cluster to be bound together by the visible matter of its galaxies. Though the idea of dark matter would not be accepted for another fifty years, Zwicky even wrote that the galaxies must be held together by some dunkle Materie. About 90% of the mass of the Coma cluster is believed to be in the form of dark matter. However, the distribution of dark matter throughout the cluster is poorly constrained.>>
Art Neuendorffer

Fossaw
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Re: Anti matter

Post by Fossaw » Fri Jul 01, 2016 11:29 am

>>> Why would matter & antimatter separate on such scales (and so cleanly)?

Apparently. In places where it was not, there would have been anhialations which, of course, leads to seperation gaps.

>>> Where are the "fireworks" at the boundaries of these outliers.

Few, far between and too faint at that distance. Possibly , a common event billions of years ago.

>>> Where are the antihelium cosmic rays?

Anhialated when entering a matter dominated region.

What is the cause of this "preponderance" in the first place? Nobody has ever explained it, simply an "accepted" state of affairs.

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neufer
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Re: Anti matter

Post by neufer » Fri Jul 01, 2016 12:03 pm

Fossaw wrote:
neufer wrote:
Where are the antihelium cosmic rays?
Anhialated [sic] when entering a matter dominated region.
  • All of them :?:
https://en.wikipedia.org/wiki/Antimatter#Observation_in_cosmic_rays wrote:
<<There is no evidence of complex antimatter atomic nuclei, such as antihelium nuclei (i.e., anti-alpha particles), in cosmic rays. These are actively being searched for.>>
Fossaw wrote:
What is the cause of this [matter/antimatter] "preponderance" in the first place?

Nobody has ever explained it, simply an "accepted" state of affairs.
https://en.wikipedia.org/wiki/Axion wrote:
The axion is a hypothetical elementary particle postulated in 1977 to resolve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a specific range, they are of interest as a possible component of cold dark matter. In 1983, Pierre Sikivie showed that axions can be detected on Earth by converting them to photons, using a strong magnetic field, the principle of the ADMX. Many experiments are searching laser light for signs of axions.>>
https://arxiv.org/abs/1407.0030 wrote:
Baryogenesis from Strong CP Violation and the QCD Axion
Geraldine Servant

<<The strong CP-violating parameter is small today as indicated by constraints on the neutron electric dipole moment. In the early universe, the QCD axion has not yet relaxed to its QCD-cancelling minimum and it is natural to wonder whether this large CP violation could be responsible for baryogenesis. We show that strong CP violation from the QCD axion can be responsible for the matter antimatter asymmetry of the universe in the context of cold electroweak (EW) baryogenesis if the EW phase transition is delayed below the GeV scale. This can occur naturally if the Higgs couples to a O(100) GeV dilaton. The only new relevant ingredients beyond the Standard Model in our framework are the QCD axion and an EW scale dilaton-like scalar field. The existence of such a second scalar resonance with a mass and properties similar to the Higgs boson will soon be tested at the LHC. In this context, the QCD axion would not only solve the strong CP problem, but also the matter anti-matter asymmetry and dark matter.>>
Art Neuendorffer

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neufer
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Re: Anti matter

Post by neufer » Sat Jul 07, 2018 1:16 pm

neufer wrote:
https://en.wikipedia.org/wiki/Axion wrote:
The axion is a hypothetical elementary particle postulated in 1977 to resolve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a specific range, they are of interest as a possible component of cold dark matter. In 1983, Pierre Sikivie showed that axions can be detected on Earth by converting them to photons, using a strong magnetic field, the principle of the ADMX. Many experiments are searching laser light for signs of axions.>>
https://arxiv.org/abs/1407.0030 wrote:
Baryogenesis from Strong CP Violation and the QCD Axion
Geraldine Servant

<<The strong CP-violating parameter is small today as indicated by constraints on the neutron electric dipole moment. In the early universe, the QCD axion has not yet relaxed to its QCD-cancelling minimum and it is natural to wonder whether this large CP violation could be responsible for baryogenesis. We show that strong CP violation from the QCD axion can be responsible for the matter antimatter asymmetry of the universe in the context of cold electroweak (EW) baryogenesis if the EW phase transition is delayed below the GeV scale. This can occur naturally if the Higgs couples to a O(100) GeV dilaton. The only new relevant ingredients beyond the Standard Model in our framework are the QCD axion and an EW scale dilaton-like scalar field. The existence of such a second scalar resonance with a mass and properties similar to the Higgs boson will soon be tested at the LHC. In this context, the QCD axion would not only solve the strong CP problem, but also the matter anti-matter asymmetry and dark matter.>>
https://arxiv.org/abs/0912.0004 wrote:
  • Higgs in Space!
C.B. Jackson, Geraldine Servant, Gabe Shaughnessy, Tim M.P. Tait, Marco Taoso
(Submitted on 30 Nov 2009 (v1), last revised 18 Mar 2010 (this version, v2))

Click to play embedded YouTube video.
<<We consider the possibility that the Higgs can be produced in dark matter annihilations, appearing as a line in the spectrum of gamma rays at an energy determined by the masses of the WIMP and the Higgs itself. We argue that this phenomenon occurs generally in models in which the the dark sector has large couplings to the most massive states of the SM and provide a simple example inspired by the Randall-Sundrum vision of dark matter, whose 4d dual corresponds to electroweak symmetry-breaking by strong dynamics which respect global symmetries that guarantee a stable WIMP. The dark matter is a Dirac fermion that couples to a Z' acting as a portal to the Standard Model through its strong coupling to top quarks. Annihilation into light standard model degrees of freedom is suppressed and generates a feeble continuum spectrum of gamma rays. Loops of top quarks mediate annihilation into gamma Z, gamma h, and gamma Z', providing a forest of lines in the spectrum. Such models can be probed by the Fermi/GLAST satellite and ground-based Air Cherenkov telescopes.>>
Art Neuendorffer