[alpha2cen]

How fast can we move particles by using current technology? And, do we find any physical property changes at that high speed?
Are there any experimental limit to increase a particle speed?
We know electrons or protons are usually used for making very high speed particles.

[Schrödinger's hat]

alpha2cen, on 19 September 2011 - 02:30 PM, said:

How fast can we move particles by using current technology? And, do we find any physical property changes at that high speed?
Are there any experimental limit to increase a particle speed?
We know electrons or protons are usually used for making very high speed particles.

The LHC is the state of the art and it accelerates proton beams to 3.5 TeV, or about 0.9999c, or gamma of approximately 3700 if I did the conversions right.
They're going to turn it up to full power eventually (7TeV for proton beams), so double the energy for a speed of roughly 0.99994c.
In terms of physical property changes you'll probably have to be more specific.
Are you asking about relativistic effects from being in a different frame (eg. the time of a moving object moves slower in our frame)? Or something else? Particle accelerators are designed to produce unusual physics when the beams collide rather than when they are moving.

[imatfaal]

As Mr Hat said we usually look at collisions (or in fact the debris created by collisions) rather than the particle in motion - how could we look at the particle without it colliding with something? One result that shows an ability to understand how things change in motion is quite interesting. If we experiment on heavy ion collisions at very high speed we get a slightly different result than expected in our models (if we used nice spherical ions in the computer). If however we used flattened discs in the computer simulations instead of spheres (ie length contracted) then we get a much higher degree of agreement with real results. It is not direct - but it is a nice way of probing how things behave at very high speeds

[Schrödinger's hat]

imatfaal, on 19 September 2011 - 04:26 PM, said:

As Mr Hat said we usually look at collisions (or in fact the debris created by collisions) rather than the particle in motion - how could we look at the particle without it colliding with something? One result that shows an ability to understand how things change in motion is quite interesting. If we experiment on heavy ion collisions at very high speed we get a slightly different result than expected in our models (if we used nice spherical ions in the computer). If however we used flattened discs in the computer simulations instead of spheres (ie length contracted) then we get a much higher degree of agreement with real results. It is not direct - but it is a nice way of probing how things behave at very high speeds

*peers*
I don't quite comprehend. Wouldn't any model that you're using in a particle accelerator be Lorentz invariant at the very very least?

[alpha2cen]

Schrödinger, on 19 September 2011 - 03:43 PM, said:

In terms of physical property changes you'll probably have to be more specific.
Are you asking about relativistic effects from being in a different frame (eg. the time of a moving object moves slower in our frame)? Or something else? Particle accelerators are designed to produce unusual physics when the beams collide rather than when they are moving.

At the string theory, we think particles as string, i.e., waves. Then, at the very high speed state we can observe the particles' wave length are very short than low speed state. So, if particles are waves, the physical property may be changed.

[IM Egdall]

alpha2cen, on 19 September 2011 - 02:30 PM, said:

How fast can we move particles by using current technology? And, do we find any physical property changes at that high speed?
Are there any experimental limit to increase a particle speed?
We know electrons or protons are usually used for making very high speed particles.

I just read in Relativity for the Questioning Mind by Daniel Styer, 2011, p. 92 that "no electron at CERN has traveled as fast as or faster than light"(no surprise here). "The maximum speed achieved so far is 0.999 999 999 997 c."

[alpha2cen]

IM Egdall, on 19 September 2011 - 11:11 PM, said:

"The maximum speed achieved so far is 0.999 999 999 997 c."

How do we know the electron speed is 0.999 999 999 997 c? It has probably some velocity distribution. Is the average velocity at the maximum 0.999 999 999 997C?
If we constructs more bigger diameter hadron collider than LHC, we only change the 12th number under the decimal point. Is it right?

This post has been edited by alpha2cen: 20 September 2011 - 08:07 AM

[imatfaal]

Schrödinger, on 19 September 2011 - 09:48 PM, said:

*peers*
I don't quite comprehend. Wouldn't any model that you're using in a particle accelerator be Lorentz invariant at the very very least?

I don't think there was a eureka moment when a researcher realised where he was going wrong


- perhaps a little over dramatizing on my part, although I am not alone I read it in those terms at the RHIC website (and I am pretty sure those guys understand lorentz contraction)

[Schrödinger's hat]

alpha2cen, on 20 September 2011 - 08:06 AM, said:

How do we know the electron speed is 0.999 999 999 997 c? It has probably some velocity distribution. Is the average velocity at the maximum 0.999 999 999 997C?

Well, we cheat slightly in that we just calculated the velocities off of the energies/potentials used.
But there are clocks accurate enough to measure velocities this high if you had a circular accelerator. Just count the EM pulses as your Ion's go by, multiply by the distance around your accelerator (I don't know to what accuracy this is known, probably not 12 sig figs so by this measurement technique you'd probably have 0.999999c+/-0.000001c) and divide by the time.

Quote

If we constructs more bigger diameter hadron collider than LHC, we only change the 12th number under the decimal point. Is it right?

Yes, no matter how much kinetic energy we put in to the electrons (even thousands or millions of times as much) we'll only asymtotically approach c.
For the LHC accelerating protons, there is around 3700 times as much energy-momentum (the generalisation of mass) in the proton as it would have at rest.

imatfaal, on 20 September 2011 - 11:36 AM, said:

I don't think there was a eureka moment when a researcher realised where he was going wrong


- perhaps a little over dramatizing on my part, although I am not alone I read it in those terms at the RHIC website (and I am pretty sure those guys understand lorentz contraction)

Do you have a link to the specific page? I don't doubt what you're saying, but I'm curious as to what they were talking about.

[imatfaal]

Schrödinger, on 22 September 2011 - 04:29 AM, said:

Do you have a link to the specific page? I don't doubt what you're saying, but I'm curious as to what they were talking about.

Well - whilst with one ion travelling at relativistic speed you can choose any frame (including the frame of the ion) that would allow you to model the ion as non-contracted, with two ions travelling in opposite directions there cannot exist a frame in which at least one ion isn't length contracted

[Schrödinger's hat]

imatfaal, on 22 September 2011 - 12:39 PM, said:

Well - whilst with one ion travelling at relativistic speed you can choose any frame (including the frame of the ion) that would allow you to model the ion as non-contracted, with two ions travelling in opposite directions there cannot exist a frame in which at least one ion isn't length contracted

I'm....uh...confused. This doesn't appear to be a response to what I think I posted.
I was querying the implication that someone working at a particle accelerator would ever have a reason to run a non-relativistic simulation (and thus wondering about the circumstances around such an event).
I was definitely not questioning the suitability of a relativistic model in this situation.

[imatfaal]

Schrödinger, on 22 September 2011 - 07:56 PM, said:

I'm....uh...confused. This doesn't appear to be a response to what I think I posted.
I was querying the implication that someone working at a particle accelerator would ever have a reason to run a non-relativistic simulation (and thus wondering about the circumstances around such an event).
I was definitely not questioning the suitability of a relativistic model in this situation.

Oh I understand. It was a pop-science/children's introduction on the front page of the site, rather than a serious scientific explanation of their train of thought. But I was reminded of it when it was asked if there were any physical property changes at high speed. Length contraction is notoriously difficult to show - so it would make sense to use differential modelling to confirm it - but obviously only as side issue.

[morgsboi]

OVER THE SPEED OF LIGHT!!


http://www.bbc.co.uk...onment-15017484