Dark Matter vs Dark Energy

(Jeffery) wrote in message


Also monopoles are predicted by grand unified theories, and one of the
benefits of infdlation is that it solves the monopole problem.

What is the "monopole problem"?

As far as we know "magnetic field" is a relativistic effect
showing up every time when an electrically charged particle
moves. It is quite well understood and so it is quite well
understood why it is only apparent field and so surely not
generated by any "monopoles".

If you postulate existence of "monopoles" they must obviously
produce a different "magnetic field" than the one mentioned
above but we don't know (since we never observed it) properties
of such "field". So you are postulating existence of particles
with unknown properties (at least unknown relation to what we
call "magnetic field"). Do they exist? Do "magnetic shmonopoles"
exist? Why not?

You may postulate existence of any number of non observed
phenomena and particles responsible for them and of course
it won't be possible to prove that they don't exist. We just
don't need to believe that they exist and this lack of any
need for them is the best argument against them.

-- Jim

(Jeffery) wrote in message


Also monopoles are predicted by grand unified theories, and one of the
benefits of infdlation is that it solves the monopole problem.

What is the "monopole problem"?

As far as we know "magnetic field" is a relativistic effect
showing up every time when an electrically charged particle
moves. It is quite well understood and so it is quite well
understood why it is only apparent field and so surely not
generated by any "monopoles".

If you postulate existence of "monopoles" they must obviously
produce a different "magnetic field" than the one mentioned
above but we don't know (since we never observed it) properties
of such "field". So you are postulating existence of particles
with unknown properties (at least unknown relation to what we
call "magnetic field"). Do they exist? Do "magnetic shmonopoles"
exist? Why not?

You may postulate existence of any number of non observed
phenomena and particles responsible for them and of course
it won't be possible to prove that they don't exist. We just
don't need to believe that they exist and this lack of any
need for them is the best argument against them.

-- Jim

[s.a.r. mod. note: followups to s.p.r., please -- mjh]

You are talking about nonsupersymmetric SU(5). When you include
supersymmetry, it predicts a much higher proton lifetime. The reason
is basically as follows. All particles have a self-energy caused by
constantly emitting and reabsorbing virtual particles, which we then
explain away using renormalization. The self-energy consists of
emitting virtual particles of all the different types of particles in
existence. In supersymmetric models, there are twice the number of
particles in existence, which means particles are constantly emitting
and reabsorbing all the heavy supersymmetric particles, which effects
the renormalization. This then changes the renormalization group and
equations and the beta equations. This changes the running of the
coupling constants, and in fact it causes the coupling constants to
converge. In grand unified theory all by itself, the coupling
constants almost converge but not quite. In grand unification combined
with supersymmetry, they exactly converge. The point where they
converge, would be the point at which grand unified theory is broken.
The GUT scale would be at about 10^16 GeV, which means the X and Y
bosons called leptoquarks would have masses about 10^16 GeV, which is
higher than grand unification without supersymmetry. Therefore
supersymmetry causes the X and Y bosons to have higher mass. If they
have higher mass, they have shorter range, and so it would be rarer
that two particles will stray close enough to exchange one.
Thereforefore they will lower cross section. Proton decay is caused by
the exchange of X and Y bosons. If this happens more rarely, protons
will decay more rarely, and the proton lifetime is rarer. Without
supersymmetry, the proton has a lifetime of 10^30 years whch has been
ruled out by experiment. If you include supersymmetry, the proton has
a lifetime of 10^32 years which has not been ruled out, and can never
be ruled out because you can't distinguish it from the intrinsic
background caused by neutrinos.

Now about inflation. If you watch ice freezing on a pond, the entire
surface doesn't freeze at once, and the ice doesn't expand from a
single point. Different parts of the ice freeze, and then when these
different sections meet there is a zig zag boundary between them. In
the liquid water, the molecules are unoriented, and when they freeze
they become oriented, and in different parts of the pond, they point
in different directions. The boundaries between them are called
topological defects. The freezing of water breaks the isotropic
symmetry of the water molecules. The same thing happens in the early
universe. The early universe, such as as at the grand unification
breaking scale goes through symmetry breaking. The Higgs field was
originally not pointing in any direction, but then when it undergoes
symmetry breaking, it ends up pointing in a random direction. In parts
of the universe that aren't casually connected, the Higgs field points
in different directions. Then as time goes on, they come in contact,
and the boundaries between them are topological defects. There are
different types of topological defects due to the different types of
symmetry breaking and the orientation of the fields, such as
monopoles, strings, domain walls, textures, or skyrmions. Grand
Unified Theory predicts that magneti monopoles would be created in
great profusion. However, we have never detected one. This is called
the monopole problem and is one of the three main problems with the
traditional Big Bang model, the other two being the flatness problem
and horizon problem. All three of these problems can be solved with
inflation. Let's say that the universe underwent an enormous expansion
at the beginning of its existence. A sphere with a radius of the
planck length could expand to several orders of magnitude larger than
the current observable universe in just the planck time. Therefore, it
would very unlikely that there would be any monopoles within our
current observable universe.

If you don't like the fact that the Standard Model just links the
groups together to form SU(3) x SU(2) x U(1), then go ahead and use
SU(5), SO(10), supersymmetric SU(5) or SO(10), SO(32), or E_8 x E_8.

Jeffery Winkler

http://www.geocities.com/jefferywinkler

[s.a.r. mod. note: followups to s.p.r., please -- mjh]

You are talking about nonsupersymmetric SU(5). When you include
supersymmetry, it predicts a much higher proton lifetime. The reason
is basically as follows. All particles have a self-energy caused by
constantly emitting and reabsorbing virtual particles, which we then
explain away using renormalization. The self-energy consists of
emitting virtual particles of all the different types of particles in
existence. In supersymmetric models, there are twice the number of
particles in existence, which means particles are constantly emitting
and reabsorbing all the heavy supersymmetric particles, which effects
the renormalization. This then changes the renormalization group and
equations and the beta equations. This changes the running of the
coupling constants, and in fact it causes the coupling constants to
converge. In grand unified theory all by itself, the coupling
constants almost converge but not quite. In grand unification combined
with supersymmetry, they exactly converge. The point where they
converge, would be the point at which grand unified theory is broken.
The GUT scale would be at about 10^16 GeV, which means the X and Y
bosons called leptoquarks would have masses about 10^16 GeV, which is
higher than grand unification without supersymmetry. Therefore
supersymmetry causes the X and Y bosons to have higher mass. If they
have higher mass, they have shorter range, and so it would be rarer
that two particles will stray close enough to exchange one.
Thereforefore they will lower cross section. Proton decay is caused by
the exchange of X and Y bosons. If this happens more rarely, protons
will decay more rarely, and the proton lifetime is rarer. Without
supersymmetry, the proton has a lifetime of 10^30 years whch has been
ruled out by experiment. If you include supersymmetry, the proton has
a lifetime of 10^32 years which has not been ruled out, and can never
be ruled out because you can't distinguish it from the intrinsic
background caused by neutrinos.

Now about inflation. If you watch ice freezing on a pond, the entire
surface doesn't freeze at once, and the ice doesn't expand from a
single point. Different parts of the ice freeze, and then when these
different sections meet there is a zig zag boundary between them. In
the liquid water, the molecules are unoriented, and when they freeze
they become oriented, and in different parts of the pond, they point
in different directions. The boundaries between them are called
topological defects. The freezing of water breaks the isotropic
symmetry of the water molecules. The same thing happens in the early
universe. The early universe, such as as at the grand unification
breaking scale goes through symmetry breaking. The Higgs field was
originally not pointing in any direction, but then when it undergoes
symmetry breaking, it ends up pointing in a random direction. In parts
of the universe that aren't casually connected, the Higgs field points
in different directions. Then as time goes on, they come in contact,
and the boundaries between them are topological defects. There are
different types of topological defects due to the different types of
symmetry breaking and the orientation of the fields, such as
monopoles, strings, domain walls, textures, or skyrmions. Grand
Unified Theory predicts that magneti monopoles would be created in
great profusion. However, we have never detected one. This is called
the monopole problem and is one of the three main problems with the
traditional Big Bang model, the other two being the flatness problem
and horizon problem. All three of these problems can be solved with
inflation. Let's say that the universe underwent an enormous expansion
at the beginning of its existence. A sphere with a radius of the
planck length could expand to several orders of magnitude larger than
the current observable universe in just the planck time. Therefore, it
would very unlikely that there would be any monopoles within our
current observable universe.

If you don't like the fact that the Standard Model just links the
groups together to form SU(3) x SU(2) x U(1), then go ahead and use
SU(5), SO(10), supersymmetric SU(5) or SO(10), SO(32), or E_8 x E_8.

Jeffery Winkler

http://www.geocities.com/jefferywinkler