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...
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?
In the chapter on partial wave analysis in Griffiths's Introduction to Quantum Mechanics, he considers a spherically symmetric potential and says that for large r, the radial part of Schrodinger's equation becomes,
\frac{d^{2}u}{dr^{2}}≈-k^{2}u
with a general solution of...
Thanks for the reply! If both chirality and helicity are flipped for both particle and antiparticle, then what's the consequence of them having opposite relative parity? Doesn't the +1 eigenvalue case mean that the function is left unchanged under the parity operation?
A quark and antiquark have opposite parity. The quark is customarily taken to have positive parity. I understand this to mean that Pf = f, where f is the wavefunction of the quark and Pg = -g, where g is the wavefunction of the antiquark.
Does this mean that P acting on an antiquark...
I am reading a paper where the bending power of a dipole magnet is described as 2 Tm. Is that Tesla*meter? Is bending power actually power i.e. Work/Time? Can someone explain this physical quantity to me, please?
As an example, consider the
La_{57} (J^P=2^-) → Ce_{58} (J^P=0^+) decay and I'd like to figure out what the angular momentum and spin state of the electron-neutrino system is.
I get the right answer, when I require l=1 as this carries P=-1 making P conserved and S_{enu}=1 to conserve angular...
I am reading about group theory in particle physics and I'm slightly confused about the word "representation".
Namely, it is sometimes said that the three lightest quarks form a representation of SU(3), or that the three colors do.
But at the same time, it is said that a group can be...
I am confused about when and to what extent parity is violated in weak decays.
On the one hand, there's Wu's famous experiment where electrons are emitted preferentially in one direction. This parity violation can be said to be maximal, since all electrons are emitted in one direction...
Homework Statement
I am confused about parity violation in weak decays. I learned about Wu's famous experiment and how it demonstrates that parity is violated in weak decays.
However, when I am doing a course problem on nuclear β-decay, then it still necessary to conserve parity...
OK, so I've figured out that the answer is no I shouldn't multply by 3*10^8 squared again. The mass would be the same number in MeV/c^2 as it is in MeV, only in the latter case it's measured in natural units.
But to rephrase my question: if the number didn't change when going from MeV/c^2 to...
I'm slightly confused about natural units.
Take mass as an example: I can measure something in kg's, but then decide to convert to MeV/c^2, for instance. To do that I would multiply the quantity in kg by 3*10^8 squared and divide by 10^6*1.6*1-^(-19) i.e. the SI values of the constants. If I...
The parity operator has eigenvalues of +/- 1 and particles can have intrinsic parity of +/- 1. What does it matter? Does a P=-1 particle behave physically different from a P=+1 particle?
Is parity a useful concept only in the sense that one can check if an interaction conserves parity (parity...
At the beginning of cpt 9, Griffiths states that massive bosons have three polarization states (m_s = 1, 0, -1), but massless ones have only two (m_s = 1, -1). Are these polarization states the same thing as helicity states? I.e. the W/Z would have 3 helicity states and the photon only 2?
Thank you for your replies!
For massive particles, a real particle is one which lies on mass shell i.e. E^2-p^2*c^2=m^2*c^4. For a virtual particle the equals sign doesn't apply and one can get different values for m other than the true value of m.
However, a photon is massless, so what...