Recent content by JoePhysicsNut

Quantum Mechanics and Path Integrals: Emended Edition by Richard P. Feynman (Author), Albert R. Hibbs (Author), Daniel F. Styer (Editor)

What's the definition of invariant pT in a 2->2 process? I know how to calculate the invariant mass in this case, but I am not sure about pT.

Thanks to you both!

I've heard of cosmic rays affecting measurements made at the LHC in the context of muons. Is it just muons that can reach the detectors or is there background from other particles as well? Why are muons a background but not electrons? How significant is it? Thanks.

Thanks for the reply! But again, is there a qualitative way of understanding why it's phase velocity not group velocity? True, refraction of light is also controlled by c/n - the phase velocity. Refraction can be understood from Fermat's principle, but again I don't know why it's one type of...

Why must the charged particle that leads to Cherenkov radiation travel faster than the phase velocity of light not the group velocity of light? One of the sides of the triangle that is used to define cosθ is v=c/n i.e. the phase velocity. I don't see why it's one rather than the other. Thanks!

I had a look at the production cross sections for W/Z at hadron colliders. These differ as a function of energy with the W x-sec being consistently ~10 times larger than the Z cross sections. Why is the W cross section so much larger? I think the coupling strength is similar and the mass...

Why is it necessary to use Monte Carlo methods in high energy physics? There is Feynman calculus to evaluate matrix elements for various interactions and the relativistic Fermi's Golden Rule for decays and scattering to obtain a decay width or differential cross section. What are we...

Actually i think i know what the answer is. Since the quarks inside the mesons are distinguishable (antiquark and quark) then their combination doesn't have a symmetry requirement.

I was mixing it up yes! So but taking the overall wavefn of the quarks then. As fermions they must be anti-symmetric overall. If the spins are different for the two mesons, then what else is also different?

Both Rho^0 and Pi^0 are bosons so require an overall symmetric wavefn. However, they are in different spin states: the Pi is in the anti-symmetric S=0 state and the Rho is in one of the symmetric S=1 states. Which other part of the overall wavefn (color, flavor, spatial) differs between the two...

Thanks for a thorough answer!

The W couples to left-handed particles only. What about the Z? Is it the same? Thanks in advance!

Dear all, I am using some software to perform a two-sample Kolmogorov–Smirnov test. Specifically, I am testing the compatibility of two histograms. The function returns a single number that is 1 for a perfect match (when I compare the histogram to itself) and somewhere between 0.05 to 0.25...

Thanks! The operator yields the momentum for the first term and (-1)*momentum for the second. A negative magnitude for momentum does not make sense, so therefore it is to be evaluated for times t<0 making it the incoming wave. Is that the argument?