Tuesday, March 12, 2019

Magnetic monopoles

Mining the CMS beam pipe for monopoles: The old section of beam pipe from the collision region in the CMS experiment (at the Large Hadron Collider) is going to be ground up and fed through superconducting loops, probably with a SQUID.

Good old Maxwell's Equations say that if you have a perfectly conducting loop and you shoot a charged particle through it, there will start to be a current in one direction, which will rise, fall, and die away as the particle passes through and away from the loop.

But if you shoot a magnetic monopole through such a loop, there will start to be a current in one direction which will rise and level off, leaving a constant current flowing through the loop where there was none before.

Nobody knows if there are magnetic monopoles. A bar magnet has North and South poles, and by no contortions can you split or twist it to get an isolated North pole. It would be nice to have some, but despite years of looking nobody has found any.

But maybe, just maybe, some heavy monopoles were made during the years of high energy particle bombardment during the first CMS run. (They didn't see any clear evidence for candidates during the analysis of their detector.)

If monopoles were heavy enough, they might have been stopped inside the 1/10 inch thick material of the beam pipe. If you grind up the material (it is toxic, btw, and was probably radioactive too) and feed it through the loops, maybe you'll see the current rise and not fall again.

That would be, if I may put it mildly, very exciting.

Picture taken from Dzhordzhadze et al. The upper plot simulates the way a current would change with an ordinary charged particle and a monopole. Arbitrary units, and without pesky background noise.

No comments: