Can antiparticales be seen or can they only be detected?
We won't be able to "see" antiparticles in the literal sense, but we can detect them.
This statement applies to normal matter as well.
We can't really "see" electrons in the sense that we see them with our eyes by detecting light bouncing off of them. That can't happen, since electrons are much smaller than the wavelengths of visible light.
On the other hand we can "detect" them by seeing light they give off when they hit a phosphorescent screen, etc.
The same will go for all particles smaller than the wavelength of visible light. We won't be able to see them in the literal sense, but we have different ways of detecting them (cloud chambers. bubble chambers, etc.)
Please don't let "amount we have available on earth" confuse this discussion:
Yes, antipartcles look the same. They interact with photons, and form baryons and atoms just like their counterparts.
That is not correct, and would be like saying you can't see atoms because they are smaller than the wavelengths of visible light.
Electrons themselves can emit enough light to be seen (if you looked through the window of a synchrotron without protection to see the electrons you'd be blinded).
In the end of course, our eye is just a photon detector. The detector at colliders are just more advanced detectors (which can detect more than photons as well).
The positron was discovered in 1933 by observing tracks in a cloud chamber that behaved like electron tracks but curved in the opposite direction in a magnetic field.
Similarly, in bubble chambers, antiparticle tracks look just like particle tracks except for having opposite curvature. When I was a grad student, I saw many examples of electron-positron pairs produced by photons. As the electrons and positrons lost energy and momentum via multiple scattering in the chamber fluid, their tracks curled up in a distinctive pattern.
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