Particle physics

Particle physics (also high energy physics) is the branch of physics that studies the nature of the particles that constitute matter and radiation.

Quotes

 * Instead of three species of elementary particle which were known in the 1920s, we now have sixty-one. Instead of three states of matter... we now have six or more. Instead of a few succinct equations to summarize the universe of physics, we now have a luxuriant growth of mathematical structures, as diverse as the phenomena that they attempt to describe. So we have to come back to the rain forest, intellectually as well as geographically.
 * Freeman Dyson, Infinite in All Directions: Gifford Lectures given at Aberdeen, Scotland April-November 1985 (1988) p. 7 (paperback, 1989).


 * I recently listened to a talk by a famous biologist. He spoke about... scientific materialism and religious transcendentalism. He said, "...they are incompatible and mutually exclusive." This seems to be a widely accepted view... I do not share it. I do not know what the word "materialism" means. ...I judge matter to be an imprecise and ...old-fashioned concept ...[M]atter is the way particles behave when a large number of them are lumped together. When we examine matter in the finest detail in experiments of particle physics, we see it behaving as an active agent... Its actions are... unpredictable. It makes what appear to be arbitrary choices between alternative possibilities. Between matter... and mind... there seems to be only a difference of degree... We stand... midway between the unpredictability of matter and the unpredictability of God. This view... may not be true, but it is... logically consistent and compatible with... experiments of modern physics. Therefore... scientific materialism and religious transcendentalism are neither incompatible nor mutually exclusive. We have learned that matter... does not limit God's freedom to make it do what he pleases.
 * Freeman Dyson, Infinite in All Directions: Gifford Lectures given at Aberdeen, Scotland April-November 1985 (1988) pp. 7-8 (paperback, 1989).


 * Someone said imagine that CERN (where the World Wide Web was invented for particle physics) had one penny for each use, then particle physics would have all the funding it could use.
 * Stephen Hawking and Gordon Kane: (p. 5)


 * It can rightly be said that symmetry, gauge theories, and spontaneous symmetry breaking have been the three pegs upon which modern particle physics rests.


 * During the SSC debate, Anderson and other condensed-matter physicists repeatedly made the point that the knowledge gained in elementary-particle physics would be unlikely to help them to understand emergent phenomena like superconductivity. This is certainly true, but I think beside the point, because that is not why we are studying elementary particles; our aim is to push back the reductive frontier, to get closer to whatever simple and general theory accounts for everything in nature. ... experience shows that the ideas developed in one field can prove very useful in the other. Sometimes these ideas become transformed in translation, so that they even pick up a renewed value to the field in which they were first conceived. The example that concerns me is an idea that elementary-particle physicists learnt from condensed-matter theory – specifically from the BCS theory. It is the idea of spontaneous symmetry breaking.
 * Steven Weinberg: