| Topic: |
Science > Physics |
| User: |
"Golden Boar" |
| Date: |
16 Jan 2005 08:11:16 PM |
| Object: |
Are all hadrons colourless? |
Since the proton is comprised of quarks with colour charge, and the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black & white, to
keep with the colour scheme).
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| User: "Gregory L. Hansen" |
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| Title: Re: Are all hadrons colourless? |
16 Jan 2005 08:23:18 PM |
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In article <1105927876.734661.86700@z14g2000cwz.googlegroups.com>,
Golden Boar <goldenboar@hotmail.com> wrote:
Since the proton is comprised of quarks with colour charge, and the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black & white, to
keep with the colour scheme).
I hadn't thought of that before-- identifying baryon number with net
color.
--
Irony: "Small businesses want relief from the flood of spam clogging their
in-boxes, but they fear a proposed national 'Do Not Spam' registry will
make it impossible to use e-mail as a marketing tool."
http://www.bizjournals.com/houston/stories/2003/11/10/newscolumn6.html
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| User: "Creighton Hogg" |
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| Title: Re: Are all hadrons colourless? |
16 Jan 2005 08:29:03 PM |
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On Mon, 17 Jan 2005, Gregory L. Hansen wrote:
In article <1105927876.734661.86700@z14g2000cwz.googlegroups.com>,
Golden Boar <goldenboar@hotmail.com> wrote:
Since the proton is comprised of quarks with colour charge, and the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black & white, to
keep with the colour scheme).
I hadn't thought of that before-- identifying baryon number with net
color.
Doesn't really work though. Mesons and baryons are all colorless, but
mesons have zero baryon number and (anti)baryons have a number of (-)1.
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| User: "Golden Boar" |
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| Title: Re: Are all hadrons colourless? |
17 Jan 2005 01:35:13 PM |
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Creighton Hogg wrote:
On Mon, 17 Jan 2005, Gregory L. Hansen wrote:
In article <1105927876.734661.86700@z14g2000cwz.googlegroups.com>,
Golden Boar <goldenboar@hotmail.com> wrote:
Since the proton is comprised of quarks with colour charge, and
the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black &
white, to
keep with the colour scheme).
I hadn't thought of that before-- identifying baryon number with
net
color.
Doesn't really work though. Mesons and baryons are all colorless,
but
mesons have zero baryon number and (anti)baryons have a number of
(-)1.
If a proton is considered to be white and an anti-proton to be black,
then you could say quarks have a colour charge of 1/3 white and
anti-quarks have a colour charge of 1/3 black. The meson is then made
from an equal amount of black and white colour charge - creating grey.
What properties would "grey charged" particles have?
If they contained an equal amount of black and white charge, the
charges would cancel each other out, making the grey charge a neutral
one.
This would then mean that the black and white charges were not neutral
after all, and could be considered as positive and negative.
This would give rise to hadrons having a positive, neutral, or negative
net colour charge.
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| User: "" |
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| Title: Re: Are all hadrons colourless? |
19 Jan 2005 05:04:24 PM |
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Golden Boar wrote:
If a proton is considered to be white and an anti-proton to be black,
then you could say quarks have a colour charge of 1/3 white and
anti-quarks have a colour charge of 1/3 black.
That's the Baryon number. More precisely, the quantum number permitted
by quantum field theory would be (Baryon - Lepton). This is what plays
the analogous role of "brightness" in color space (color charge is,
then, saturation, the 2 dimensions of the SU(3) charge are the
"chromaticity coordinates").
Electrons have B-L = -1; that's what I called "black" in the table I
presented. Positrons +1 ("white"); protons +1, anti-protons -1.
What properties would "grey charged" particles have?
There's no force (yet) known that corresponds to or contains the
quantum number B-L. If there were, it would satisfy either the Maxwell
or Proca equations, the latter giving you, in effect, a static field of
the form exp(-kr)/r^2. Like charges would repel, unlike charges
attract. It would show up as a '5th force' or would be confused with
an extra [anti-]gravitational force. So, undoubtedly, you will find
something searching under "5th force", "baryon number", "anti-gravity"
or combinations thereof.
The mesons would be neutral.
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| User: "Creighton Hogg" |
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| Title: Re: Are all hadrons colourless? |
17 Jan 2005 01:46:51 PM |
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On 17 Jan 2005, Golden Boar wrote:
Creighton Hogg wrote:
On Mon, 17 Jan 2005, Gregory L. Hansen wrote:
In article <1105927876.734661.86700@z14g2000cwz.googlegroups.com>,
Golden Boar <goldenboar@hotmail.com> wrote:
Since the proton is comprised of quarks with colour charge, and
the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black &
white, to
keep with the colour scheme).
I hadn't thought of that before-- identifying baryon number with
net
color.
Doesn't really work though. Mesons and baryons are all colorless,
but
mesons have zero baryon number and (anti)baryons have a number of
(-)1.
If a proton is considered to be white and an anti-proton to be black,
then you could say quarks have a colour charge of 1/3 white and
anti-quarks have a colour charge of 1/3 black. The meson is then made
from an equal amount of black and white colour charge - creating grey.
Well, except that's now how color charge works at all. Color charge is
given the labels R,G,B because there are three kinds of charges and an
SU(3) symmetry between them. The only ways to get "white" are RGB or
RantiR,BantiB,GantiG. It is quite wrong to say that quarks have a white
color charge. The whole point is that the growth of the QCD coupling
constant at long range confines all colored objects into colorless
bunches.
What properties would "grey charged" particles have?
If they contained an equal amount of black and white charge, the
charges would cancel each other out, making the grey charge a neutral
one.
This would then mean that the black and white charges were not neutral
after all, and could be considered as positive and negative.
This would give rise to hadrons having a positive, neutral, or negative
net colour charge.
As I have explained above, this is wrong. If hadrons had some net color
charge, then they would be bound together just as quarks are bound
together and you'd never see them. That doesn't happen.
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| User: "Golden Boar" |
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| Title: Re: Are all hadrons colourless? |
17 Jan 2005 05:08:22 PM |
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Creighton Hogg wrote:
Well, except that's now how color charge works at all.
Color charge is given the labels R,G,B because there are
three kinds of charges and an SU(3) symmetry between them.
The only ways to get "white" are RGB or RantiR,BantiB,
GantiG. It is quite wrong to say that quarks have a white
color charge. The whole point is that the growth of the QCD
coupling constant at long range confines all colored
objects into colorless bunches.
As I have explained above, this is wrong. If hadrons had
some net color charge, then they would be bound together
just as quarks are bound together and you'd never see them.
That doesn't happen.
Thinking in an artistic sense for a moment, black, white and grey are
not classesd as colours - but as colourless shades.
I got myself a bit confused there for a moment. Black, white, and grey
charged hadrons would all be colourless.
Baryons would be colourless white.
Anti-baryons would be colourless black.
Mesons would be colourless grey.
Mesons being grey, would decay into black and white particles. In the
case of the pion, these particles would be the muon which would be
white, and the muon anti-neutrino which would be black
The white muon would decay into a white muon neutrino, a white
electron, and a black electron anti-neutrino.
The above pion decay process showed the electron to be white and the
electron anti-neutrino to be black. This would then require the W boson
to be grey. When a white neutron decays into a white proton, it creates
a grey W boson, which in turn decays into a white electron and black
anti-neutrino.
This model does more than identify baryon number. It shows the
conservation of baryon number, baryon to lepton transformation, and
conservation of lepton number - all from the colour charge of the
quarks, which is conserved.
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| User: "Creighton Hogg" |
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| Title: Re: Are all hadrons colourless? |
17 Jan 2005 05:21:49 PM |
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On 17 Jan 2005, Golden Boar wrote:
Creighton Hogg wrote:
Well, except that's now how color charge works at all.
Color charge is given the labels R,G,B because there are
three kinds of charges and an SU(3) symmetry between them.
The only ways to get "white" are RGB or RantiR,BantiB,
GantiG. It is quite wrong to say that quarks have a white
color charge. The whole point is that the growth of the QCD
coupling constant at long range confines all colored
objects into colorless bunches.
As I have explained above, this is wrong. If hadrons had
some net color charge, then they would be bound together
just as quarks are bound together and you'd never see them.
That doesn't happen.
Thinking in an artistic sense for a moment, black, white and grey are
not classesd as colours - but as colourless shades.
I got myself a bit confused there for a moment. Black, white, and grey
charged hadrons would all be colourless.
Baryons would be colourless white.
Anti-baryons would be colourless black.
Mesons would be colourless grey.
Mesons being grey, would decay into black and white particles. In the
case of the pion, these particles would be the muon which would be
white, and the muon anti-neutrino which would be black
The white muon would decay into a white muon neutrino, a white
electron, and a black electron anti-neutrino.
The above pion decay process showed the electron to be white and the
electron anti-neutrino to be black. This would then require the W boson
to be grey. When a white neutron decays into a white proton, it creates
a grey W boson, which in turn decays into a white electron and black
anti-neutrino.
This model does more than identify baryon number. It shows the
conservation of baryon number, baryon to lepton transformation, and
conservation of lepton number - all from the colour charge of the
quarks, which is conserved.
Except that it's not really related to color charge at all. How would a black
or a grey particle transform under SU(3)? A singlet is a singlet, which
means white is the only kindof colorless there is.
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| User: "Golden Boar" |
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| Title: Re: Are all hadrons colourless? |
19 Jan 2005 02:34:52 AM |
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No idea, you tell me!
What's SU(3)? what's a singlet? What do you mean by transform?
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| User: "annelies" |
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| Title: Re: Are all hadrons colourless? |
19 Jan 2005 10:14:05 AM |
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If you can tell me what your background is in mathematics and physics,
then I can have a look to see what book I should recommend you about the
subject!
Kind regards,
Annelies
Golden Boar wrote:
No idea, you tell me!
What's SU(3)? what's a singlet? What do you mean by transform?
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| User: "Creighton Hogg" |
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| Title: Re: Are all hadrons colourless? |
16 Jan 2005 08:18:18 PM |
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On 16 Jan 2005, Golden Boar wrote:
Since the proton is comprised of quarks with colour charge, and the
anti-proton is comprised of anti-quarks with anti-colour charge,
shouldn't the proton have a net colour of colourless and the
anti-proton have a net colour of anti-colourless (or black & white, to
keep with the colour scheme).
All observed hadrons are colorless by the nature of confinement and the
running of the coupling constant for QCD. I suppose you could define
colorless and anti-colorless, but it's vacuous in the same way that
negative zero is vacuous.
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