How can LHC control subatomic particles so finely that they can smash together sub atomic particles travelling close to C with such accuracy?
In: Physics
The combination of vanishingly small sizes and relativistic speeds seem like they’d make the “aiming” of the particles almost impossible.
Oh it’s not accurate at all. Well relatively speaking. It’s still really really good, but they aren’t shooting a single proton at another and expecting results.
The vast majority miss, and the vast majority of those that hit hit off center.
To mitigate this they send the particles around in bunches large enough they get ~~a single~~ around 20 collisions per bunch the majority of the time. When particles collide off center there isn’t enough energy to spit out interesting new particles in interesting paths so the data gets thrown out.
(Edit: They seem to aim for around 20 collisions per bunch. Presumably most of those collisions are off center so can be separated out relatively easily)
If the data can’t be interpreted it gets thrown out. Additionally they have multiple bunches running the circle at the same time with a few thousand bunches following after each other in the ring, each circling around 10,000 or so times per second.
And even then a lot of the data they get is still uninteresting for new discoveries, and gets filtered out as well.
The LHC spits out a mind boggling amount of data, like a Petabyte per second. Even after throwing almost all of it away as not useful they run these experiments for months and CERN has like an Exabyte of storage capability for saving the “interesting” collisions. Afterward it can still take months of processing to filter for specific collisions and aggregate the data using statistics to get more precise values for things like particle mass.
They are using magnets to aim. But yes even then its hard thats why they use billions of particles and only a very low % of them hit anything. In other words if you cant hit with a sniper rifle use a few million machine guns and hope some bullets hit.
Its not one particle at a time. It is billions. So they are not shooting guns at each other, they are shooting shotguns. Some particles/bullets hit each other, most do not.
To clarify (maybe) what others are saying, it is not the case that the LHC is firing two protons at each other. It is creating two beams that are traveling in opposite directions. As the particles within the beams pass by each other, some collide.
The particle beams are about the width of a human hair, and contain billions of particles.
They can’t control the particles finely enough, so they make up for that by using billions of them.
The chance of two bullets colliding in mid-air is low if you only fire one each.
But fire billions of bullets, and you’re bound to see a collision.
A bit of topic but can someone explain how they measure these tiny collisions and how can they track the path of the collision induced sub particles so precisely. What instrument is used?
Billions of particles being shot through something thinner than a human hair results in some collisions per second
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