B The Paradox of Mass Distortion in Collider Experiments

[idea2000]

When a collider such as the lhc accelerates two protons side by side, would thy seem to gain mass and then distort st? And if so, would the lab frame see them attract each other? How would the attraction be explained from the perspective of each particle, if they don't see the other particle gain mass?

 

[PeterDonis]

When a collider such as the lhc accelerates two protons side by side, would thy seem to gain mass and then distort st?

No. The energy of an object is frame-dependent; but the gravity produced by an object is not.

would the lab frame see them attract each other?

No.

 

[idea2000]

So when thy are accelerated, they gain mass, but, they don't distort st?

 

[idea2000]

When protons collide, do they create new particles that distort st? And, do protons distort st the same way whether they are moving or at rest?

 

[PeterDonis]

when thy are accelerated, they gain mass

No. They gain energy with respect to the lab frame, but energy is frame-dependent. (Some old texts use the term "relativistic mass", but that is really just another name for energy.)

but, they don't distort st?

The source of gravity is not mass. It's the stress-energy tensor, which includes energy, momentum, pressure, and other stresses, in a way that ensures that the gravity produced by an object is frame-independent.

 

[PeterDonis]

When protons collide, do they create new particles

They can, yes.

that distort st?

The spacetime curvature produced by protons, or any other particles produced in accelerator experiments, is negligible.

do protons distort st the same way whether they are moving or at rest?

Yes, because "moving" and "at rest" are frame-dependent, and as I already said, the gravity produced by an object (i.e., the spacetime curvature produced) is not frame-dependent.

 

[idea2000]

When protons collide, does all that extra energy they have become converted into new particles who's total rest mass is greater than the rest mass of the two protons before they were accelerated?

Thanks for your replies, btw!

 

[PeterDonis]

When protons collide, does all that extra energy they have become converted into new particles who's total rest mass is greater than the rest mass of the two protons before they were accelerated?

It can be, yes. But the extra rest mass comes from the energy added by the accelerator; it doesn't come out of nowhere. And spacetime curvature, as I said, is produced by stress-energy, not mass ("mass" is one form of stress-energy, but not the only one). So whatever spacetime curvature is being produced by the particles that come out, it's the same as whatever spacetime curvature was being produced by the energy in the accelerator beforehand. (Actually, both are negligible, but conceptually, it's still important to understand that energy conservation applies.)