Mathematical Field Notes

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Resonances

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How could you “detect” a new subatomic particle, given that it’s so small you can’t see it and (often) so short-lived that you’d miss it even if you didn’t blink?

Let’s suppose you have a process which you think might involve your tiny, short-lived new friends. Maybe you suspect that if you smash protons together, you might produce some particles… which decay into particles…. which decay into the particles you’re looking for… which then themselves decay almost immediately into something else, something that is more stable and easier to detect (something like a pair of photons). How could you check that you were right?

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Written by Jonny Evans

October 30, 2016 at 12:02 pm

Is the speed of light constant?

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I recently came across a beautiful argument due to De Sitter (1913), which gave the (first?) experimental evidence that light moves with a constant speed.

Constancy of the speed of light is one of those things that always bothered me, and I spent a couple of days recently trying to unbother myself. De Sitter’s argument is what finally satisfied me. Below, I’m going to explain the background, then I’ll explain De Sitter’s argument. The De Sitter paper is only a couple of paragraphs long and is available via Wikisource, so if you don’t need the introductory remarks in the blogpost below, just follow the link above and read it.

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Written by Jonny Evans

August 9, 2016 at 5:33 pm

Posted in Physics

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