Recent content by Mithra

Hi guys, I'm sure I'm being very stupid here but I'm reading through notes which contain various actions for fields, most of which are very similar, however there is some discrepancies with the way differential operators are shown acting on the fields and I can't for the life of me work out...

Hi, sorry if this is in the wrong place, not really sure whether it should be homework questions or here! I'm writing my final year paper and frequently mention mesons and quarks by their symbols and am unsure whether I should be italicizing them? My latex package for writing them easily...

Aha brilliant, that makes a lot more sense now. Thanks very much for such a clear explanation! :)

Well I guess in the model we're looking at here it is heavier than that.

Our lecturer explained to us that when a stationary Higgs decays into a W+W- pair, which then each decay into an electron/neutrino pair that the electrons will be collimated, however I'm struggling to understand why. He seemed to explain that the leptons would tend to have spin in one direction...

Hi, I'm wondering if anyone can give me some advice on working out the vertex factor from a lagrangian. I think I know what I should be doing however it isn't quite getting the right answer so if anyone could guide me that would be great. \mathcal{L}_{W^-e^-\nu_e} =...

Ah yes, that was the other one I was thinking of, thanks :). Of course yeah thinking about it in terms of actual fields rather than just maths a two field vertex wouldn't make much sense would it! :P And yeah that's what I was referring to sorry, always a mistake not to use latex!

Awesome, thanks very much. Would a diagram with a single line for the two fields and a 'bubble' as a line with each end vertex having a loop be valid then? For the next part a similar question is asked with a phi^3 correlator and two-loop disconnected diagrams at order \lambda^3. With the...

I've been given an action of S = -\frac{1}{2}m^2\phi^2 - \frac{\lambda}{3!}\phi^3 and the question then require drawing the feynman diagrams for the <\phi\phi> at order \lambda^2. I am told that there are 2 connected diagrams at one-loop order and one disconnected two-loop diagram and...

Ah brilliant, thanks very much! I thought it must be related to the Heaviside function, but could only seem to find Theta function. A little embarrassing having not heard of these as a fourth year physicist but hey ho :P. Cheers.

Hi, I'm reading through a paper and have come across what my tutor described as a 'theta function', however it seems to bear no resemblance to the actual 'theta function' I can find online. In the paper it reads: \int^1_0 dz~\theta (s-\frac{4m^2}{z}-\frac{m^2}{1-z}) And apparently this...

Thanks for the help :). I got the eigenstates of S_x in terms of S_z as \frac{1}{\sqrt{2}} (|\frac{1}{2},\frac{1}{2}> + |\frac{1}{2},\frac{-1}{2}> and \frac{1}{\sqrt{2}} (|\frac{1}{2},\frac{1}{2}> - |\frac{1}{2},\frac{-1}{2}> With the first one corresponding to the same eigenvalue...

Hi there, I apologise that I should probably know this/its a stupid question but I seem to have forgotten all physics over the holiday and so any help would be great! I have been told that there is a beam of atoms with spin quantum number 1/2 and zero orbital angular momentum, with spin +1/2...

I can't transfer until October so I won't be rushing into it, don't worry :wink:.

Thanks for the advice, looks like I shall have to look into transferring course!