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What is Antimatter? - Page 3

There is no intrinsic difference between particles and antiparticles; they appear on essentially the same footing in all particle theories. This means that the laws of physics for antiparticles are almost identical to those for particles; any difference is a tiny effect. But there certainly is a dramatic difference in the numbers of these objects we find in the world around us; all the world is made of matter. Any antimatter we produce in the laboratory soon disappears because it meets up with matching matter particles and annihilates.

Modern theories of particle physics and of the evolution of the universe suggest, or even require, that antimatter and matter were equally common in the earliest stages--so why is antimatter so uncommon today? The observed imbalance between matter and antimatter is a puzzle yet to be explained. Without it, the universe today would certainly be a much less interesting place, because there would be essentially no matter left around; annihilations would have converted everything into electromagnetic radiation by now. So clearly this imbalance is a key property of the world we know. Attempts to explain it are an active area of research today.

In order to answer this question, we need to better understand that tiny part of the laws of physics that differ for matter and antimatter; without such a difference, there would be no way for an imbalance to occur. This distinction is the subject of study in a number of experiments around the world that focus on differences in the decays of particles called B-mesons and their antiparticle partners. These experiments will be done both at electron-positron collider facilities called B factories and at high-energy hadron colliders, because each type of facility offers different capabilities to contribute to the study of this detail of the laws of physics--a detail that is responsible for such an important property of the universe as the fact that there is anything there at all!


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