How about an Electroweak star?

On Jan 25, 3:24*am, " wrote:

* What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

Andrew Usher

On Jan 25, 6:04*pm, Andrew Usher wrote:
On Jan 25, 3:24*am, " wrote:

* What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

AIUI the idea goes back to the Grand Unification Theory(ies) dictum
that all bosons are the same and so are all fermions. They only *look*
different because the Universe is currently so cold that the strong
nuclear force, the weak nuclear force, electromagnetism, and
gravitation are distinguishable; so we now have distinct gluons, W/Z
bosons, photons and gravitons. The various fermions carry different
amounts of "something" that manifests as electric charge, weak charge,
color charge, and mass. Get them hot enough (bang them together or
shake them with enough energy) and the distinctions go away.

Anyway, the idea is that some neutron stars may have a core that is
hot and dense enough that the nucleons therein will merge into
something called "quark-gluon plasma" AKA "quagma". This is analogous
to a normal-matter plasma in that the constituent particles (quarks)
are no longer bound to each other as triplets in the usual way, and
the bits that used to bind them together (gluons) now flow through the
plasma freely.

The difference is that the quarks get so hot that they can no longer
be distinguished from neutrinos; their color charge flips into weak
charge, their mass becomes energy of motion and they escape the grip
of the gluon field at a high fraction of c. Thereafter they look just
like any other neutrino.

Some of their energy gets left in the gluon field keeping the quagma
hot, though nothing can maintain the pressure when enough mass is
lost, which is where the lifetime limit comes from.

It's called "burning" presumably because quarks are a higher-energy
form of fermion than neutrinos; the conversion must be exothermic.

I think I got most of that right. There are some bits that are less
than clear, like just how do you start with a neutral (in every field
except gravity) mass that seems to accumulate charges of one sort or
another as neutral particles (neutrinos) leave by the bucketload? At
those temperatures field bosons can easily interconvert meaning strict
accounting for electric, weak, strong, and color charges will involve
some fancy currency conversions at the least.


Mark L. Fergerson

Andrew Usher wrote:
On Jan 25, 3:24 am, " wrote:

What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

Andrew Usher

Word Salad, sprinkled with kooked opinions.

"Sjouke Burry" wrote in message
...
Andrew Usher wrote:
On Jan 25, 3:24 am, " wrote:

What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

Andrew Usher

Word Salad, sprinkled with kooked opinions.


There was a kooked man, and he walked a kooked mile.
He found a kooked sixpence against a kooked stile.
He bought a kooked cat, which caught a kooked mouse,
And they all lived together in a little kooked neutron star.

On Jan 25, 8:57*pm, " wrote:
On Jan 25, 6:04*pm, Andrew Usher wrote:

On Jan 25, 3:24*am, " wrote:

* What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

sorry, had to snip your guesses

I had thought that baryon number was conserved by the electroweak
force; but apparently not. I looked at the paper on which these
announcements were based ( http://arxiv.org/abs/0912.0520 ) and it
states that electroweak symmetry-breaking can violate baryon number
conservation, converting quarks to leptons, but under ordinary
conditions this is highly suppressed.

The electroweak proton-decay lifetime is said to be 10^141 yr (which
is unobservable); I had thought that proton decay required GUTs or
supersymmetry (it does for _detectable_ lifetimes, of course), but the
reference in that paper does list the electroweak decay mode, and also
a gravitational decay mode (through virtual black holes) with a
possible lifetime from that between 10^46 and 10^169 yr. So even in
the standard model, I guess, baryons are not forever. Anyway, when the
temperature and density both reach the electroweak scale (as happens
at the center of these stars), conversion becomes unsuppressed and
proceeds as fast as new fuel is fed; this will evidently (though not
discussed in the paper) continue until degeneracy pressure is alone
enough to support the star i.e. it becomes an ordinary neutron star.
The fact that stellar black holes exist at all, then, shows that this
electroweak mechanism can't stablise collapsing stars above some mass
threshold, and if this turns out to be less than the maximum mass of a
neutron star, there will be no electroweak stars at all.

One last question: since the center of these stars is highly general-
relativistic, what coordinates are they using to consistently describe
the whole star?

Andrew Usher

On Jan 25, 10:11*pm, Sjouke Burry
wrote:

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

Andrew Usher

Word Salad, sprinkled with kooked opinions.

See my latest reply - they're claiming it's a standard aspect of the
electroweak theory (though I hadn't heard of it before).

Andrew Usher

On Jan 25, 8:22*pm, Andrew Usher wrote:
On Jan 25, 8:57*pm, " wrote:

On Jan 25, 6:04*pm, Andrew Usher wrote:

On Jan 25, 3:24*am, " wrote:

* What will they look like toward the end of their lives? At some
point the "apple-sized region" will get too small or too cold to
sustain "electroweak burning", but the object could then be too small
to remain a neutron star. Will it "reinflate" to a white dwarf of some
sort?

Can someone tell me what the heck 'electroweak burning' is? I haven't
seen a good explanation here.

sorry, had to snip your guesses

Quite all right; I suppose I could have looked at the paper, too.

I had thought that baryon number was conserved by the electroweak
force; but apparently not. I looked at the paper on which these
announcements were based (http://arxiv.org/abs/0912.0520) and it
states that electroweak symmetry-breaking can violate baryon number
conservation, converting quarks to leptons, but under ordinary
conditions this is highly suppressed.

Baryon number conservation can be violated under the extreme
conditions cited but (baryon number minus lepton number) is conserved.

(I was surprised Uncle Al considered baryon number conservation as
absolute.)

The electroweak proton-decay lifetime is said to be 10^141 yr (which
is unobservable); I had thought that proton decay required GUTs or
supersymmetry (it does for _detectable_ lifetimes, of course), but the
reference in that paper does list the electroweak decay mode, and also
a gravitational decay mode (through virtual black holes) with a
possible lifetime from that between 10^46 and 10^169 yr. So even in
the standard model, I guess, baryons are not forever. Anyway, when the
temperature and density both reach the electroweak scale (as happens
at the center of these stars), conversion becomes unsuppressed and
proceeds as fast as new fuel is fed; this will evidently (though not
discussed in the paper) continue until degeneracy pressure is alone
enough to support the star i.e. it becomes an ordinary neutron star.

Mkay, I got one of the conclusions right by a "wrong" route.

The fact that stellar black holes exist at all, then, shows that this
electroweak mechanism can't stablise collapsing stars above some mass
threshold, and if this turns out to be less than the maximum mass of a
neutron star, there will be no electroweak stars at all.

One last question: since the center of these stars is highly general-
relativistic, what coordinates are they using to consistently describe
the whole star?

Rotation and convection are both ignored, and unless I'm sorely
mistaken, the cited basis for much of the paper, the Oppenheimer-
Volkoff equation is in accelerated coordinates, so there you go.


Mark L. Fergerson

On Jan 26, 1:02*am, " wrote:

* Quite all right; I suppose I could have looked at the paper, too.

I had thought that baryon number was conserved by the electroweak
force; but apparently not. I looked at the paper on which these
announcements were based (http://arxiv.org/abs/0912.0520) and it
states that electroweak symmetry-breaking can violate baryon number
conservation, converting quarks to leptons, but under ordinary
conditions this is highly suppressed.

* Baryon number conservation can be violated under the extreme
conditions cited but (baryon number minus lepton number) is conserved.

Yes, B-L is conserved in every theory we know of. What would a
universe where B != L look like?

* (I was surprised Uncle Al considered baryon number conservation as
absolute.)

Well, it's stated many places, including the Wikipedia article, that
baryon number is absolutely conserved in the standard model. Is this
really a commonly-accepted conclusion of electroweak theory, and not
just someone's speculation?

Andrew Usher

On Jan 26, 10:00 pm, Andrew Usher wrote:
On Jan 26, 1:02 am, " wrote:

Quite all right; I suppose I could have looked at the paper, too.

I had thought that baryon number was conserved by the electroweak
force; but apparently not. I looked at the paper on which these
announcements were based (http://arxiv.org/abs/0912.0520) and it
states that electroweak symmetry-breaking can violate baryon number
conservation, converting quarks to leptons, but under ordinary
conditions this is highly suppressed.

Baryon number conservation can be violated under the extreme
conditions cited but (baryon number minus lepton number) is conserved.

Yes, B-L is conserved in every theory we know of. What would a
universe where B != L look like?

Protons would decay much more easily; the Universe might never have
formed galaxies.

Hell, it might never have formed *stars*.

(I was surprised Uncle Al considered baryon number conservation as
absolute.)

Well, it's stated many places, including the Wikipedia article, that
baryon number is absolutely conserved in the standard model.

Not quite, it's *nearly* conserved.

"The baryon number is nearly conserved in all the interactions of
the Standard Model. 'Conserved' means that the sum of the baryon
number of all incoming particles is the same as the sum of the baryon
numbers of all particles resulting from the reaction. An exception is
the chiral anomaly."

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

Is this
really a commonly-accepted conclusion of electroweak theory, and not
just someone's speculation?

Fairly well-accepted; it's one (conditional) explanation of the
nonzero mass of neutrinos.

http://en.wikipedia.org/wiki/B%E2%88%92L

"If B - L exists as a symmetry, it has to be spontaneously broken to
give the neutrinos a nonzero mass if we assume the seesaw mechanism."


Mark L. Fergerson

On Jan 23, 8:41*am, Yousuf Khan wrote:
This is presumably one stage higher than a black hole, but two stages
lower than a neutron star, and one stage lower than a quark star. I'm
not sure, it's not mentioned in the article if it's lower or higher than
a quark star.

Also not mentioned in the article is what happens to this star after
about 10 million years, when the electroweak burning phase finishes?
Does it turn into a black hole, or does it turn into a neutron star or
quark star?

And how does a quark turn into a lepton? Is that in the Standard Model?

It comes from one of several *extensions* to the Standard Model.
Examples include the now defunct SU(5) supergroup, technicolor, and
some supersymmetry variants.

Or is this coming from an interpretation of one of the Superstring or
some other theories? The only thing I know about the Weak force is how
it causes atomic fission.

* * * * Yousuf Khan

***
SPACE.com -- New Type of Exotic Star Proposed
"An electroweak star could come into being toward the end of a massive
star's life, after nuclear fusion has stopped in its core, but before
the star collapses into a black hole, the researchers found.

At this point, the temperature and density inside a star could be so
high, subatomic particles called quarks (which are the building blocks
of protons and neutrons) could be converted into lighter particles
called leptons, which include electrons and neutrinos.

"In this process, which we call electroweak burning, huge amounts of
energy can be released," the researchers wrote in the scientific paper.

Unfortunately for observers, much of that energy would be in the form of
neutrinos, which are very light neutral particles that can pass through
ordinary matter without interacting, making them very difficult to detect.."http://www.space.com/scienceastronomy/exotic-star-type-proposed-10012...