Recent content by hch71

Wikipedia is a good starting point: http://en.wikipedia.org/wiki/Pair-instability_supernova

1) The Yukawa potential is an effective description of the remnant strong force between hadrons (bound states of quarks and gluons), not of the fundamental strong force between quarks and gluons. As this effective strong force is mediated by massive hadrons itself, it has a finite range. In...

In terms of exchange particles, the strong force is mediated by gluons. It has infinite range like the electromagnetic force but in contrast to it, gluons themselves are charged and therefore can not spread through all of space. They always confine quarks and themselves into bound states, the...

Gauge symmetry is not unrelated to Poincare symmetry at all. the construction i like most is this: find the two Casimirs of the poincare group - they are the square of P and of the Pauli-Lubansky vector W. The first Casimir - p^2 - is the mass. p^2=m^2 gives you the Klein-Gordon equation. If...

Actually, there is a proposition that in the center of supermassive stars the temperatures can go high enough that 1MeV photons are present and will pair-produce electrons and positrons. This would result in a sharp stellar pressure drop leading to a very bright type of core-collapse supernova.

yet another long time follower first time poster... under the assumption that there might be a leak at the bottom of the SFP#4, how clear are the conclusions from this sample measurment? i presume the probe is taken from the top layer where water is constantly added? actually, is it known...

That is correct. The mass of a quark is not a experimentally accessible quantity, but the light (up and down) quarks have a mass of ~2-5MeV. The proton on the other hand has a mass of ~940MeV. So the contribution of the individual quarks' masses is very small. The rest of the mass of the...

In fact, there is at least one area where the "chromomagnetic" aspect of the strong force is kind of physical. There is the so-called dual superconductor picture of confinement which asserts that quark confinement is due to a condensation of chromomagnetic monopoles. This is of course not a...

Actually, as far as i know there is no reason in U(1) for the charge to be quantized. If you postulate magnetic monopoles, you get the Dirac quantization condition, but if not there is no restriction.