I was wondering whether the decay of the Pi-0 meson in QED to an electron positron pair can occur as follows:
Pi-0 -> virtual photon -> e+e-
or does it have to go via
Pi-0 -> two virtual photons -> e+e- (the Feynman diagram has a 'square' of virtual electrons/photons)?
I'm struggling with the relation between particle exchange and parity with the case of para- and ortho-hydrogen.
The overall wavefunction must be antisymmetric with respect to particle exchange and so for para-hydrogen (an antisymmetric spin state) the spatial part of the wavefunction must be...
Firstly, apologies for the notation.
The 4-momentum of a massive particle (rest mass m) is defined by
where u is the 4-velocity. Thus in a frame S in which a particle has 3-velocity u the components of p are
How can we then identify the zeroth component of...
I guess you have a two cylinder system with an incompressible fluid?
For a) you may call, generally, the diameter of the red cylinder D, and thus the diameter of blue cylinder 2D. What are the areas associated with diameters? We thus may work out the volume V=Area x distance through which the...
I would start by drawing a diagram of the situation. Draw the 4 forces in, i.e. weight W, reaction force R from the floor, friction F' and the force we are pulling with F.
Since the trunk isn't moving the vertical direction, we may equate the 'downwards' forces with the 'upwards' forces, i.e...
A stone is dropped from a stationary helicopter 500m above the ground, at the equator. How far from the point vertically below the helicopter does it land?
Conversation of AM
The Attempt at a Solution
Let the height above the ground it is...
The Coulomb is the SI unit of charge. It is just a standard against which we can compare the relative charges of difference objects; just like we might say this object has a mass of 1kg, and this object has a mass of 3kg, we could say one object has 1 coulomb (C) of charge, and another has 10C...
So, the rocket equation is
F_ext = m(dv/dt) + u(dm/dt)
where m is the mass of the rocket, v the velocity, u the effective exhaust gases speed, and F_ext the external forces on the system.
If we take a constant mass ejection rate p, and take the external force to be the gravitational...