Recent content by Fek

Confused by the branching ratio of uds ---> proton + e- + neutrino compared to uds ---> proton + pion (or neutron + pion). In both cases an W boson is being produced as the strange quark changes flavour, and it is either decaying to leptons or first generation quarks - why is the leptonic...

All sorted thank you.

Homework Statement Nearly free electron model in a 2D lattice. Consider a divalent 2D metal with a square lattice and one atom per primitive lattice cell. The periodic potential has two Fourier components V10 and V11, corresponding to G = (1,0) and (1,1). Both are negative and mod(V10) >...

Have I not taken into account Kaons with the Cabibo factors (cos(x)) for non mixed states, and sin(x) for mixed states?

Sorry made a silly mistake. So the BR should be 60% for hadrons and 20% for the electron Sorry made a silly mistake. BR should now be 60% for hadrons (3 * cos^2(x) + sin^2(x)) / (3 * (cos^2(x) + sin^2(x)) + 1 + 1 ) , and 20% for each lepton. Many thanks.

I'm afraid I just can't see it. I'v Many thanks for your reply. I can see I shouldn't have include the charm containing mesons as they are slightly to heavy. This brings the branching ratios to 50% hadrons and 25% for each lepton. Have I missed something else or is the remaining discrepancy...

Homework Statement Branching ratios of tau lepton decay: hadrons 66% muon 17% electron 17% Use your knowledge of the decay of W bosons to justify these rates. Homework EquationsThe Attempt at a Solution [/B] The W+ boson can decay to any combination of quarks with +1 charge, but the CKM...

Homework Statement [/B] In Minkowski spacetime we are considering a (series of) frame(s), S', attached to a rocket with constant proper acceleration. The rocket's speed in S is v. We find with boundary conditions x = 0 at t = t' = 0 the relationships between S and S' (for x' = 0, i.e. at the...

Homework Statement Rocket is accelerating constantly. Let S' be instantaneous rest frame of rocket and S be frame in which rocket is observed moving at velocity v. Homework Equations Given: $$ dv = dv' (1 - v^2) $$ Must prove: $$ \frac{dv}{dt} = \frac{dv'}{dt'} (1 -...

Homework Statement What effect would placing an LC circuit in a steady magnetic field have have on its resonant frequency? The inductor contains a paramagnet. This is asked about at very low temperature. Homework EquationsThe Attempt at a Solution Apart from initial changes due to Lenz's Law...

Thanks for your response Chet. ∇T ≈ ΔT / s , where s is the gap between cylinders if we assume that ∇T is constant. However s is not given. The expression for κ assumes the mean free path is much less than the size of the container, so the molecules collide with each other much more frequently...

Homework Statement A vacuum flask of radius r and length l consists of two concentric cylinders separated by a narrow gap containing a gas at pressure 10^-2 Nm^-2. The liquid in the flask is at 60 degrees Celcius and the air outside is at 20 degrees celcius. Estimate the rate of heat loss by...

Homework Statement Find the velocity of the centre of mass of two photons with different energies (they happen to be approaching). Homework Equations E = hf p(photon) = E/C E=gamma(mc^2) The Attempt at a Solution I have calculated the energy of the two photons in the centre of mass...