Quarks in the LHC

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Elroch

Quantum chromodynamics is a subject in which I would surmise none of us are expert.

That being said, quarks are known by particle physicists to have mass. (This mass arises by the Higgs mechanism). Therefore quarks do not move at the speed of light. Gluons however are believed to be massless and are demonstrated by experiment to have mass less than 1.3 meV, which is a very small amount.

Athrasher11

To answer your first paragraph: from the perspective of quark A, quark B is stationary as they are traveling at the same velocity, since gluons are massless they travel at "c", and so from the perspective of quark A the gluon reaches quark B at the same time it "normally" would, as if the proton were not moving at all relative to the observer.

What you are describing would only be an issue if there were some sort of universal reference frame, which there isn't, the speed of light is constant for all observers regardless of their reference frame's velocity relative to other observers. Because of this, the quarks communicate their forces just as they would "normally" from the reference frame of the proton, the "stationary" reference frame observes a time dilation in the protons reference to account for the relative velocity.

RPaulB

Thanks for your comments cokeblob11.  The difference between the quark moving or not is the line of sight for the none moving case.  AT the time the gluon is admitted the gluon travels this line of sight to reach the quark.  In the case of the quark moving the direction to travel is not known and in all cases the distance traveled is greater.  And in both cases the gluon travels at C as you said, BUT in different directions to reach the other quark.

Elroch

They are not different cases. The case with a quark moving is the case with a quark stationary viewed from a different inertial frame.

RPaulB

Please tell us why a proton at near the velocity of C is stable.

Athrasher11

We pretty much just did, a proton traveling near c and one which is "stationary" are exactly the same. The only difference is the reference frame which you choose to observe it from. 

 

If a proton traveling near c was unstable, what would distinguish that unstable proton from a stationary one viewed from a ship moving towards it at near c? Nothing. That would mean that every proton in the universe would be unstable if viewed from the proper reference frame. 

RPaulB

Thanks for your comments cokeblob11. The difference between the quark moving or not is the line of sight for the none moving case. AT the time the gluon is admitted the gluon travels this line of sight to reach the quark. In the case of the quark moving the direction to travel is not known and in all cases the distance traveled is greater. And in both cases the gluon travels at C as you said, BUT in different directions to reach the other quark.  Try reading this again.  Did that help ?

RPaulB

With your logic: if two particles are approaching each other at nearly C and both emit a photon towards the other, the photons are approaching each other at nearly 3 times C.   The particle emitted DOES NOT include the systems velocity as well as the velocity given to it at the time of emission.   An example of this are the photons emitted from the edge of the universe to here .  Those photons ONLY go C regardless of the edge's velocity.  The excess velocity is a frequency (energy) change, redshift. 

Elroch

Yes. Every photon in empty space is moving at c to any observer or relative to any particle.

Elroch
RPaulB wrote:

Please tell us why a proton at near the velocity of C is stable.

Velocity is how fast you are moving relative to something else. A proton is a proton regardless of how fast something else is moving relative to it.

RPaulB

Boy;  you are hard to convince.  For a supernova, the neutrinos and the photons get here at the same time  from a very long distance.  The neutrinos only arrive for about 13 seconds.  NOT ONE OF THOSE PHOTONS ARE MOVING AT C relative those neutrinos.  NEARLY ALL the neutrinos PASTED the photons on the way here which is a little beside the point.  Some photons may have had a head start of 20 years.

Athrasher11

"NOT ONE OF THOSE PHOTONS ARE MOVING AT C relative those neutrinos."

 

Yes they are, this is the fundamental concept behind special relativity. The reason why the neutrinos get here first is just because they were emitted first, the photons don't escape the supernova until the outer layers of the star rebound, the neutrinos start traveling towards us as soon as the core collapses. Again, all reference frames must agree that c is constant. Imagine you are in a spaceship, you see another ship moving towards you and measure its velocity to be 0.5c. Well, if the person on the other ship were to run the same test they would measure YOUR velocity to be 0.5c. Who is right? Which one is stationary and which one is moving? Both measurements are correct, it just depends on which reference frame you choose to adopt. Now, hopefully we agree so far, velocity is relative. The other major thing to understand is that the laws of physics do not change based on your reference frame, since c is one of those laws of physics, derived from maxwells equations, then c must be constant for all observers. This is where relativistic effects come from. In order for c to remain constant, length, time, mass, and even the order in which events occur relative to one observer can all change. I would keep going but this is turning into a very large comment. If you're like me and learn more from books there is a great introductory SR book called Flat and Curved Spacetimes that I would recommend.

Elroch
cokeblob11 wrote:

"NOT ONE OF THOSE PHOTONS ARE MOVING AT C relative those neutrinos."

 

Yes they are, this is the fundamental concept behind special relativity. The reason why the neutrinos get here first is just because they were emitted first, the photons don't escape the supernova until the outer layers of the star rebound, the neutrinos start traveling towards us as soon as the core collapses. Again, all reference frames must agree that c is constant. Imagine you are in a spaceship, you see another ship moving towards you and measure its velocity to be 0.5c. Well, if the person on the other ship were to run the same test they would measure YOUR velocity to be 0.5c. Who is right? Which one is stationary and which one is moving? Both measurements are correct, it just depends on which reference frame you choose to adopt. Now, hopefully we agree so far, velocity is relative. The other major thing to understand is that the laws of physics do not change based on your reference frame, since c is one of those laws of physics, derived from maxwells equations, then c must be constant for all observers. This is where relativistic effects come from. In order for c to remain constant, length, time, mass, and even the order in which events occur relative to one observer can all change. I would keep going but this is turning into a very large comment. If you're like me and learn more from books there is a great introductory SR book called Flat and Curved Spacetimes that I would recommend.

The unintuitive point that fools RPaulB is that those neutrinos went that huge distance so close to as fast as the photons that surely the relative speed must be less than c? But the thing is that the frame of the neutrinos has massive Lorentz contraction and time dilation, and the result is that the speed of light remains constant.

RPaulB

BOTH OF YOU ARE WRONG !!   Most of those neutrinos Left AFTER the photons did !!!!    Which means Special Relativity is wrong too , so do not feel bad.  

Athrasher11

I doubt you are qualified to make the conclusion that Special Relativity is wrong since it is clear from your other comments that you don't fully understand it. Regardless, I would be very interested if you had any evidence whatsoever that the neutrinos detected from 1987a (I assume this is the supernova you are referring to) were emitted after the photons, as that would be counter to all of the observations of the event, which showed neutrino detection approximately 3 hours before the visible light detection. 

RPaulB

All the neutrinos got here in the first 13 seconds.  None later were detected. The photons  were still coming 2 years later.  That's just observations.   As for qualifications.  Turns out ONLY I know the  theory of everything.  How are you qualified ?   AND Special Relativity has two major errors, but that's your theory, you should know these errors.

Athrasher11

The fact that the neutrinos were detected first doesn't prove that they were traveling faster than the speed of light which you claimed here:

" NEARLY ALL the neutrinos PASTED the photons on the way here which is a little beside the point.  Some photons may have had a head start of 20 years."

Neutrinos are produced in core collapse, photons can come from all sorts of different sources, the photons we are collecting now come from the ionized gas around whatever remnant was produced, not the supernova itself. 

Your "theory of everything" has no basis in observation, makes no testable predictions, and looking through your post it contains no math whatsoever, how is anyone supposed to use such a theory or demonstrate its truth? Special and General Relativity on the other hand, have been proven to be reliable by every experiment designed to test their validity. Disproving them is no small task, if you claim that these are false and your ideas are better then you can't expect anyone to just take your word for it. 

Please, look into Lorentz Transformations, they essentially solve the original problem of this thread. 

RPaulB

There are 100 DIFFERENT theories on gravity since General Relativity.  Thus 99 have to be wrong.  If LT and SR are such big helps, why is it that they do not tell you which one is the CORRECT theory ?   Do you know which one is correct ? Does any of your math help ? How are you going to improve ?  Apparently your way of working physics isn't working ,  YOUR MATH seems  COMPLETELY worthless and you keep referring to it as if something great exist..    

Athrasher11

Math is what allows a theory to be tested. A mathematical model can make a quantitative prediction which can be compared to real life observations. Here's an example: B1913+16.gif

GR predicts that a pulsar binary system will lose energy over time in a very specific way, as you can see the observations match the theory exactly. If a theory is correct, it should pass any and every experiment, so far GR has which is why there is a high amount of confidence that it is correct (although probably incomplete, there are certain things which GR cannot describe like coordinate singularities but the point stands that what it can predict is correct). 

"Apparently your way of working physics isn't working"

I disagree, the current way of doing things has brought us better theories than anything else. If you think yours is better, prove it.