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Re: [Phys-L] Particle physics



On 06/18/2013 12:01 PM, Paul Lulai wrote:

We believe leptons, quarks, and some bosons are fundamental.

What do you mean by "we", Kemosabe?

As others have pointed out, fundamentalism is in the eye of
the beholder.

Besides, it's a moving target. It changes as we learn more.
Democritus thought atoms (pretty much by definition) were
fundamental.

Most importantly, who cares? Suppose I told you that XXX
was fundamental ... what would you do with the information?
The physics is what it is and does what it does. It usually
does not much care what labels we hang on things.

There are some labels that do matter, such as spin and
charge and lepton number (among others). That's because
they connect to the real physics. In particular, those
labels connect to conservation laws.

must daughter particles be fundamental?

Definitely not. For example, the thorium decay chain
produces a bunch of daughters, including radium, radon,
polonium, and others ... none of which are particularly
"fundamental" by any post-Democritus definition.

within the accelerator & detector, is there something like pair
production happening?

Sure. That's pretty much the whole point. That's why
huge energies are needed.

Also, in a proton/proton collision, you know that protons
are neither charmed nor strange. So to produce charmed
and/or strange particles, you obviously cannot do it by
simply rearranging the quarks you started with.