Magnetic monopoles found?

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Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Mon Jan 04, 2010 8:58 pm

It's from the 2003 report
It is conceivable in a theory with large extra dimensions that such a state could have a mass comparable to M∗ and thus could be produced at the LHC. Moreover, magnetic monopoles can catalyse proton decay. Can this be a problem? At each catalysis event energy is released by the decaying proton, causing the monopole to move. It is straightforward to estimate the number of protons that could be destroyed before the monopole escapes the Earth. Monopoles are expected to have a strong cross-section with normal matter. As a result the mean free path of a monopole moving through iron is given by
λ = 1/σ_strong ρ ≃ 1 cm. (23)
In the course of scattering N^2 times the monopole moves the distance λN and thus the number of scatters it experiences before escaping the Earth is determined from the condition λN = R_Earth, corresponding to N = 10^9. In each collision a nucleon is destroyed so the escaping monopole will destroy 10^18 nucleons: negligibly small compared to the total number of nucleons. Given this, we do not think it necessary to estimate the production rate for such new states because, even if there is no suppression in the production at the LHC, they do not present any conceivable threat.

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Mon Jan 04, 2010 10:03 pm

Yes, I read it. But it seems to me that the only true argument is the cosmic rays one, since even if the monopole leaves the earth, it could still do damage to the solar system.

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Tue Jan 05, 2010 12:41 am

ORION111 wrote: We have never observed a proton decay.
So we're 100% of that? Why do they bring up their calculation if it's useless?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Tue Jan 05, 2010 1:58 am

So basically the result of 10^18 is brought up only to show that light proton eating magnetic monopoles would have destroyed us already? It's pretty much meaningless, as such a monopole can't be proven to be safe without the cosmic rays argument in any case. When they say the search for monopoles in the LHC will be continued, do they refer to a different kind of monopole?

From what I understand, the safety arguments are these -
magnetic monopoles and vacuum bubbles (the most frightening objects) - aren't safe, but are ruled out by cosmic rays.
strangelets - less likely to be created in the LHC than the RHIC where they weren't created.
black holes - should decay via hawking radiation, if they don't - it would take billions of years for it to be dangerous.

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Tue Jan 05, 2010 12:05 pm

Please explain more - this is the most frightening object right after vacuum bubbles. You're saying their conclusion in 2003 about the production of magnetic monopoles not being a threat was false?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Wed Jan 06, 2010 9:42 pm

ORION111 wrote: I was talking about the same point from the perspective of 2008 report. As I have said many times before, cosmic rays don't make it possible to believe that the LHC can produce such affects. We know for sure that the cosmic rays do not produce proton decaying monopoles - not a single proton decay has ever been detected by any experiment. If the LHC indeed produces monopoles then they will not decay protons. If the LHC produces monopoles then that will also mean the cosmic rays have been producing monopoles for billions of years.
So if the LHC produces monopoles, they will be harmless ones, similar to those created in 2009?
Is there any possibility cosmic rays have been producing dangerous monopoles, but our machines were simply not effective in detecting them?

I was talking about this quote from the 2003 report -
However, such a new form of stable matter could cause a problem in a different way. Consider a magnetic monopole carrying a magnetic charge. It is conceivable in a theory with large extra dimensions that such a state could have a mass comparable to M∗ and thus could be produced at the LHC. Moreover, magnetic monopoles can catalyse proton decay. Can this be a problem? At each catalysis event energy is released by the decaying proton, causing the monopole to move. It is straightforward to estimate the number of protons that could be destroyed before the monopole escapes the Earth. Monopoles are expected to have a strong cross-section with normal matter. As a result the mean free path of a monopole moving through iron is given by
λ = 1/σ_strong ρ ≃ 1 cm. (23)
In the course of scattering N^2 times the monopole moves the distance λN and thus the number of scatters it experiences before escaping the Earth is determined from the condition λN = R_Earth, corresponding to N = 10^9. In each collision a nucleon is destroyed so the escaping monopole will destroy 10^18 nucleons: negligibly small compared to the total number of nucleons. Given this, we do not think it necessary to estimate the production rate for such new states because, even if there is no suppression in the production at the LHC, they do not present any conceivable threat.
Basically they were wrong?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Wed Jan 06, 2010 11:39 pm

I thought you said it was a fast decay rate?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Thu Jan 07, 2010 12:00 am

ORION111 wrote: Yes, if the cosmic rays were producing such monopoles in copious amounts.
So if such objects were created by the LHC, how long will it take for them to cause damage to the earth or to the solar system? (I know you said it's not possible, but "if")
ORION111 wrote: What do you mean?
In 2009 scientists created magnetic monopoles in a lab (what I wrote at the first post)

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Thu Jan 07, 2010 12:50 pm

But in unlikely event of the LHC producing dangerous magnetic monopoles, what damage will it be able to do to us and to our solar system?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Thu Jan 07, 2010 6:29 pm

But let's put aside the cosmic rays argument - can you give me an estimation of the time it would take for these monopoles to destroy the earth?

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Thu Jan 07, 2010 7:31 pm

How could you know that, other than basing this assumption on cosmic rays?

JNW
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Re: Magnetic monopoles found?

Post by JNW » Thu Jan 07, 2010 11:24 pm

ORION111 wrote:The cosmic rays do exactly the same type of stuff what the LHC does.
I'm not so sure.

It takes a cosmic ray proton traveling at 10^17 eV and hitting a stationary proton to have the same CM energy as the LHC has with colliding protons.

We know that many low energy cosmic rays are protons, but what do we know about cosmic rays of 10^17 eV and higher? We know that they produce an impressive burst of secondary particles, but do we have any information about what the original particle was?

It looks to me like assuming these particles are protons is pure guesswork, and a poor guess at that. These particles aren't affected by the GZK limit that limits the energy of protons. Perhaps all these particles are something else, such as magnetic monopoles.

So we have no real proof that a cosmic ray proton of 10^17 eV or higher has ever struck earth. Thus, the LHC may soon be doing proton-proton collisions of a higher energy than any that have ever happened before on this planet.


MUUURRRHHHAAAHHHAAAHHHAAA :Big Vampire:

Stephen
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Re: Magnetic monopoles found?

Post by Stephen » Fri Jan 08, 2010 11:52 am

ORION111 wrote: You can understand from here why even the proton-decaying monopoles are safe.
In each collision a nucleon is destroyed so the escaping monopole will destroy 10^18 nucleons: negligibly small compared to the total number of nucleons. Given this, we do not think it necessary to estimate the production rate for such new states because, even if there is no suppression in the production at the LHC, they do not present any conceivable threat.
That's exactly what I'm worrying about - how long does it take for it to destroy 10^18? The monopoles leave the earth, but what happens to our solar system after that? Can it come back to earth or damage our sun?

Does JNW have a point in what he's saying? :sad-pacing:

Shadowdraxx
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Re: Magnetic monopoles found?

Post by Shadowdraxx » Fri Jan 08, 2010 4:46 pm

JNW wrote:
ORION111 wrote:The cosmic rays do exactly the same type of stuff what the LHC does.
I'm not so sure.

It takes a cosmic ray proton traveling at 10^17 eV and hitting a stationary proton to have the same CM energy as the LHC has with colliding protons.

We know that many low energy cosmic rays are protons, but what do we know about cosmic rays of 10^17 eV and higher? We know that they produce an impressive burst of secondary particles, but do we have any information about what the original particle was?

It looks to me like assuming these particles are protons is pure guesswork, and a poor guess at that. These particles aren't affected by the GZK limit that limits the energy of protons. Perhaps all these particles are something else, such as magnetic monopoles.

So we have no real proof that a cosmic ray proton of 10^17 eV or higher has ever struck earth. Thus, the LHC may soon be doing proton-proton collisions of a higher energy than any that have ever happened before on this planet.


MUUURRRHHHAAAHHHAAAHHHAAA :Big Vampire:
This is a joke isnt it?

As a note tho i'd like to add this isnt the personal theory section its called the science section for a reason if your going to comment or add to discussion please backup your arguments, with experimental data or accepted theory work, cheers.

JNW
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Re: Magnetic monopoles found?

Post by JNW » Sat Jan 09, 2010 3:53 am

ORION111 wrote:
JNW wrote:It takes a cosmic ray proton traveling at 10^17 eV and hitting a stationary proton to have the same CM energy as the LHC has with colliding protons.
This makes no sense.

The LHC's center-of-mass proton+proton collision energy is 1.4 x 10^13 eV.
The 10^17 eV is from a CERN safety report: http://cern.ch/lsag/LSAG-Report.pdf
CERN wrote: The LHC is designed to collide two counter-rotating beams of protons or
heavy ions. Proton-proton collisions are foreseen at an energy of 7 TeV per
beam. An equivalent energy in the centre of mass would be obtained in the
collision of a cosmic-ray proton with a fixed target such as the Earth or some
other astronomical body if its energy reaches or exceeds 10^8 GeV, i.e., 10^17 eV.
ORION111, perhaps you should tell the CERN physicists that they don't make sense. :shock: :lol:

With energies well below the rest mass of the proton (about 10^9 eV) shooting a beam of protons against a stationary proton target works great. About half the energy of a beam proton is available in the CM (Center of Mass) frame. Using ten times the energy per proton gives ten times the CM energy.

With energies well above 10^9 eV, relativistic effects change things dramatically. To get ten times the CM energy requires 100 times the energy per proton in the beam. That's why all the highest energy accelerators use colliding beams, which allows all energy of both beams to be available in the CM frame.

The LHC has an energy of around 10^4 times the rest mass of the proton, so to duplicate that with a fixed target requires energies around 10^8 times the 10^9 eV rest mass of the proton, or around 10^17 eV.

So maybe the CERN physicists are right after all. :thumbup:

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