Question: What is the tiniest particle you have ever seen?

Deepak Kar answered on 11 Mar 2014:

Very interesting question!

In our experiments, we no longer “see” a particle directly. All we get to know is the path of the particle inside our detector, and how much energy it has. An example:

This shows a how a real collision looks like 🙂
Here the two yellow lines are electrons, and we get them in our detector. From their energy and direction, we calculate that a particle called Z-boson was produced in the collision, and decayed into the electron-pair. This is the closest we go to “seeing” tiny particles in the detector!

Now in the strictest sense you can say we only see photons, because our eyes only see light reflected from other objects. Going beyond that, there are quite common experiments which you will do in college where you get to see electrons. They are very tiny indeed.