Recent content by JoePhysicsNut

  1. J

    Path Integrals in QFT: Beyond Peskin's Reference

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

    Calculating Invariant pT in 2->2 Processes

    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.
  3. J

    Are Cosmic Rays Impacting the LHC Measurements Beyond Muons?

    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.
  4. J

    Cherenkov radiation - phase velocity not group velocity

    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...
  5. J

    Cherenkov radiation - phase velocity not group velocity

    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!
  6. J

    Why is the W cross section so much larger than the Z cross section?

    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...
  7. J

    Monte Carlo in high energy physics

    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...
  8. J

    Wavefn symmetry requirement

    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.
  9. J

    Wavefn 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?
  10. J

    Wavefn symmetry requirement

    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...
  11. J

    Weak force coupling to left-handed particles

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

    Understanding the Kolmogorov–Smirnov test

    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...
  13. J

    Partial wave analysis - incoming/outgoing?

    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?
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