cern-summer-webfest/readmore/three_generations.html

<p>So now you know about almost every particle in the standard
model. All that is left is the Higgs boson, which you will see in the
last chapter.</p>


<h2>Why do we not see any of these new, heavier particles? </h2>


<p>Why are there no atoms made of charm quarks, strange quarks and
muons? The answer is that the heavy particles are very unstable, and
quickly transform into their lighter brothers. Heavy particles are
produced in very high energy collisions, such as in particle
accelerator experiments. They are also found in cosmic rays – very
energetic particles that fall to Earth from space, and that are
produced in places as exotic like the core of the sun or even a
supernova explosion.</p>

<h2>Outlook</h2>
<p>Why are there so many particles? Why do three generations exist
rather than just one? The answer is simple: nobody knows!</p>

<p>And there is more to come: You have probably heard of antimatter,
haven’t you? This is what the next chapter will explain.</p>