Matter and Anti-Matter

  • #1

Main Question or Discussion Point

If equal amount of matter and anti-matter was created during the Big Bang, what is existing now? Matter?

Thanks.
 

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  • #2
phinds
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It is believed that there were NOT equal amounts created, but a very tiny imbalance which is what allowed the remaining stuff to exist. We call that remaining stuff matter but had the opposite stuff been what was predominantly left over and we had evolved anyway, we would call IT matter.

EDIT: Oh, yes ... another theory is that there WERE equal amounts created but for some reason the laws of physics don't quite apply equally to antimatter, but for now that is speculation. Actually, it's ALL speculation since it isn't known either way why there is an imbalance.
 
  • #3
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http://en.wikipedia.org/wiki/Baryogenesis

... baryogenesis is the generic term for hypothetical physical processes that produced an asymmetry between baryons and antibaryons in the very early universe, resulting in the substantial amounts of residual matter that make up the universe today.
it is puzzling that the universe does not have equal amounts of matter and antimatter. .......There are two main interpretations for this disparity: either the universe began with a small preference for matter ....or the universe was originally perfectly symmetric, but somehow a set of phenomena contributed to a small imbalance in favour of matter over time.
 
  • #4
Delta2
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Why do we have to assume the presence of antimatter in first place anyway? ( ive to admit i vent read any good books on big bang theory).
 
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  • #5
Drakkith
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Why do we have to assume the presence of antimatter in first place anyway? ( ive to admit i vent read any good books on big bang theory).
The energies right after the big bang were so high that high radiation and matter/antimatter pairs were constantly being created and annihilated until the temperature of the universe dropped too low for matter/antimatter creation to take place. Conservation and symmetry laws require that matter and antimatter be created in equal amounts, so unless something violates one of these laws, there should have been equal amounts of matter and antimatter. Since we live in a matter dominated universe, we assume that some decay process violates one of these laws, we just don't know exactly how the occurs yet.
 
  • #6
Chronos
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It has been estimated baryon asymmetry was on the order of 1 part per billion in the early universe. For reasons unknown, particle production was very slightly skewed in favor of matter. It is generally believed this was the consequence of some sort of subtle CP violation under high energy conditions - e.g., http://arxiv.org/abs/1101.2161, Source of CP Violation for the Baryon Asymmetry of the Universe.
 
  • #7
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... But baryons annihilation remains constant according to observation or am i missing something? http://www.slac.stanford.edu/pubs/beamline/26/1/26-1-sather.pdf

Now quark(bottom-quark forward-backward asymmetries) is the suspect then comes z-boson.. http://arxiv.org/abs/1406.3262.. that attenuate the effect asymmetry. How does higgs gives a different mass value to quarks that lead top quarks to move forward more often? Why does a massless particle suddenly has mass when subject to moving. Even the slight indifference of mass can produced asymmetry. Now i'm confused.

http://profmattstrassler.com/articl...cted-asymmetries-in-the-production-of-quarks/

http://www.sci-news.com/physics/science-higgs-boson-fermions-cern-02010.html
 
  • #8
Delta2
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So what you actually saying is that due to some unknown process which probably involves violation of some symmetry laws, antimatter very slowly but steady was converted to matter+ (perhaps ) energy?
 
  • #9
Chronos
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I would agree that some of the M-AM annihilation energy produced an excess of matter for reasons unknown.
 
  • #10
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So what you actually saying is that due to some unknown process which probably involves violation of some symmetry laws, antimatter very slowly but steady was converted to matter+ (perhaps ) energy?
According to what i've read. There is a static solution of the bosonic sector of the electroweak standard model known as sphaleron that somehow converts quarks to 2 anti quarks and anti-lepton vice versa.

http://en.wikipedia.org/wiki/Sphaleron

http://www.helsinki.fi/~donofrio/donofrio_lattice.pdf

".... At temperatures
above the electroweak scale, the rate of the sphaleron
transitions is unsuppressed and has been accurately
measured using effective theories on the lattice. At
temperatures substantially below the electroweak scale, the
Higgs field expectation value is large and the sphaleron rate is
strongly suppressed"
 

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