Recent content by kaksmet

Hi, a simple question on W boson vertices (and I guess field theory in general). If I have a W boson vertex for incoming particles, i.e. W^+ ubar d and W^- u dbar how do I change this for outgoing W's. The first interaction contains a CKM matrix element Vud and the second a Vud^*, and...

The reason the normal (collinear) PDFs does not depend on transverse momenta is because the transverse momenta has been integrated over. If one does not perform the integrals one get so called unintegrated/transverse momentum dependent distributions. For transverse momentum dependent...

Hello, there is a bit of confusion in this thread originating from the difference between helicity and chirality. Left/Right handed chirality is a property of a particle which is independent of reference frame (i.e. a lorentz invariant). Left/Right handed helicity is not. Helicity is the...

In other words: Yes, we mean to say that the total number of all the atomic particles in the diameter of 12000km of the Earth is as good as not there, from the perspective of a neutrino.

The key in this case, but it cannot be generally stated that that is the case. A safe way to figure this out is to see what quarks/leptons exist in initial and final state and then write down feynman diagrams describing the transition from one into the other. If it can occur via the strong...

If one talks about the Higgs as it is described in the standard model enough data should be collected this year to exclude it OR to see some hint of where it might be. This means that the question about a standard model higgs might be settled next summer, and should definitely be settled with...

Very nice explanation Tom!

Mass does not require dimension. Take for example the electron, it is a pointlike particle and hence have no spatial dimensions but it does have a mass.

No, if the gluon splits up into a red c, the c_bar cannot be anti-red; as far as I understand.

which, since they have different color/anticolor does not form a color neutral state.

And since you can choose the zero of your potential energy to be at any point the particle can have any temperature?

I believe that it is you who did not understand me. True, it is not the excitation that give the particles their mass, it is the vacuum expectation value. However, I would say that the statement that the Higgs has nothing to do with gravity and not give particle masses is misleading in such a...

Indeed, even though "nothing to do with particle masses" is quite a strong statement for a particle which comes from the excitation of the field which give the particles their mass.

Almost wrong. The interaction with the Higgs field give particles their mass.

How is collapsing equivalent to loosing energy? So, you are saying that a particle with less energy would be warmer? Let the 100 GeV particle loose its kinetic energy so that it decreases to 2.5 keV, should then have a higher temperature?