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Author Topic: I'm puzzled about the creation of particles.  (Read 3259 times)

Offline DoctorBeaver

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I'm puzzled about the creation of particles.
« on: 25/07/2007 18:51:51 »
I've been reading about particle colliders and how very high energies are needed to create certain types of particle. I just about understand the physics behind that but what I don't understand is how are they created in the natural world.

For instance, the book I'm currently reading states that energy as high as 1019GeV could be needed to create a graviton. But gravity is all around us which means that gravitons must exist anyway. So how are they created naturally if such enormous energies are required?


 

Offline G-1 Theory

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I'm puzzled about the creation of particles.
« Reply #1 on: 25/07/2007 18:58:32 »
I've been reading about particle colliders and how very high energies are needed to create certain types of particle. I just about understand the physics behind that but what I don't understand is how are they created in the natural world.

For instance, the book I'm currently reading states that energy as high as 1019GeV could be needed to create a graviton. But gravity is all around us which means that gravitons must exist anyway. So how are they created naturally if such enormous energies are required?

All that I can tell you is that gravition's are only in THEORY---At this time????!
Ed
« Last Edit: 25/07/2007 19:00:29 by G-1 Theory »
 

Offline syhprum

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I'm puzzled about the creation of particles.
« Reply #2 on: 25/07/2007 19:03:13 »
Simple! they were created in the big bang when such energies were commonplace and enough time has not yet elapsed for them to decay.
 

Offline DoctorBeaver

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I'm puzzled about the creation of particles.
« Reply #3 on: 25/07/2007 19:31:26 »
Simple! they were created in the big bang when such energies were commonplace and enough time has not yet elapsed for them to decay.

So all the gravitons that have ever existed or ever will exist were created by the Big Bang?
 

Offline Soul Surfer

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I'm puzzled about the creation of particles.
« Reply #4 on: 26/07/2007 00:09:34 »
Matter(particles) and energy (moving particles photons etc) are interchangable and all made out of the same sort of stuff(whatever that is) and so can be interchaned acording to strict physical rules during collisions so if you smash two light particles for example protons or electrons together with really enormous energies(like they do in accelerators) you can get lots of particles and less energy coming out.

As for large energy needing to create gravitions that might be true to create an observable graviton but my understanding is that gravitons are like photons and there is no lower limit for their energy so as gravitation is a very slow weak force compared with electromagnetic forces most gravitions have extremely tiny energies and there are vast numbers of them.
 

Offline syhprum

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I'm puzzled about the creation of particles.
« Reply #5 on: 26/07/2007 06:32:23 »
I have always understood that if Gravitons exist they are of very low mass (I have seen the figure of 10^-11 times that of the neutrino quoted in an 'Scientific American' article).
I would be interested to know the source of this high mass figure.
I think the term observable might be the clue here.
« Last Edit: 26/07/2007 06:36:29 by syhprum »
 

Offline DoctorBeaver

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I'm puzzled about the creation of particles.
« Reply #6 on: 26/07/2007 08:34:22 »
I have always understood that if Gravitons exist they are of very low mass (I have seen the figure of 10^-11 times that of the neutrino quoted in an 'Scientific American' article).
I would be interested to know the source of this high mass figure.
I think the term observable might be the clue here.

As far as I understand it, the hierarchy problem in particle physics is the huge disparity between the weak scale and gravity. Weak scale particles could be created at around 1TeV but the energy needed to create gravitons is a million billion times greater.

I've read those figures in quite a few sources but the book I'm currently reading is "Warped Passages" by Lisa Randall. Here's a link to her CV:-

http://randall.physics.harvard.edu/CV.html

I think she knows her stuff!  ;D
« Last Edit: 26/07/2007 09:37:00 by DoctorBeaver »
 

Offline Soul Surfer

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I'm puzzled about the creation of particles.
« Reply #7 on: 01/08/2007 10:32:10 »
The required energies are because you need to get the particles close enough together against their electrical charges to experience a gravitiational action.  Remember that the only particles that we can control and accelerate and observe easily are charged ones. This tends to skew the image of what is going on.

In theory there should be gravitational interactions between neutral particles but observing them is very difficult.

The most likely place to observe a gravitational interection between two particles would I think be in an electron positron head on collision where the charge would not be a barrier.  A classic two body gravitational interaction would cause the electrons and positrons to reverse and come back exactly the way they came with exactly the same energy as they went in.  Unfortunately that's exactly what would happen if they had a linear electromagnetic interaction and I can't for now think of any way in which it would be possible to distinguish between the gravitiational and the electromagnetic interaction unless possibly you could use the earth's gravitiational field to sort them out.
 

Offline syhprum

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I'm puzzled about the creation of particles.
« Reply #8 on: 01/08/2007 12:04:21 »
This reinforces what I have read that it will never be possible to observe individual Gravitons although effects en-mass are all too obvious
 

Offline DoctorBeaver

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I'm puzzled about the creation of particles.
« Reply #9 on: 02/08/2007 08:57:08 »
The required energies are because you need to get the particles close enough together against their electrical charges to experience a gravitiational action.  Remember that the only particles that we can control and accelerate and observe easily are charged ones. This tends to skew the image of what is going on.


Ah, that's the bit I was forgetting. I had read that somewhere but my little beaver brain threw a wobbly. Thanks Ian.

This reinforces what I have read that it will never be possible to observe individual Gravitons although effects en-mass are all too obvious

There was mention of that. The book also talked about observing K-K particles as a way of confirming the existence of gravitons as higher-dimensional particles.

It's all clever stuff!  [8D]
« Last Edit: 02/08/2007 08:59:47 by DoctorBeaver »
 

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I'm puzzled about the creation of particles.
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