Scattering Definition and 820 Threads

At next to leading order, a photon may couple to gluon via means of a quark loop insertion. Consider the process $$ \gamma(k_1) + g(p_1) \rightarrow \gamma(k_2) + g(p_2)$$ Apparantly there are eight diagrams at one loop contributing to this process and two are zero on grounds of colour...

Hello, I'm studying the setup of distributed Brillouin sensor (using fibre optics) and don't quite understand the purpose of EOM in the sensor. It says that "to generate both the pump and the probe waves from a single physical light source by using an electro-optical modulator (EOM)", but since...

I am reading through Bailin and Love's argument (see P.151-152 of 'Introduction to Gauge Field Theory') that as ##Q^2 \rightarrow \infty##, we probe the product of the two electromagnetic currents appearing in the hadronic tensor for DIS on the lightcone. I will write out the argument here and...

So I'm studying scattering and size parameters now, I've come to understand that the sky is blue because the size parameter is such that it's an excellent "scatterer" of blue-violet visible light, and horrible at red-orange, that let's pass, and such the sun is yellow within the Earth. I've also...

origin page : http://www.physicspages.com/2012/08/08/finite-step-potential-scattering/ No quite understand how the solution come from this equation

Is there some way to - from an intuition standpoint - justify the fact that there should be a factor of ##a^{6}##, (where ##a ## is the particle diameter) in the Rayleigh Scattering formula? I've seen a few sources hint that there should be. I can follow the derivation from e.g a Lorentz atom...

I read many times that the early universe was opaque foremost because of the scattering of photons off free electrons (Thomson scattering). Why is the scattering off free protons not equally important? Btw, the same they say about stars. Photons within stars need a very long time to get out of...

Homework Statement [/B] (Note: this is not strictly homework, but it is related to one course I'm doing, and I can't find a useful solution anywhere) Find the analytical expression for the scattering cross section of two longitudinally polarized electrons at tree level. Homework Equations...

Homework Statement This is just a simple proof of substitution, but after one day struggle, I still can't get where that minus sign appear. Homework Equations Here is the equation: $$ (p_1 - p_3)^2=-(\mathbf p_1 - \mathbf p_3)^2$$ where ##p_1=(E/c,\mathbf p_1)## and ##p_3=(E/c, \mathbf p_3)##...

Homework Statement Two identical charged particles, each of mass m and charge e, are intitialy far apart. One of the particles is at rest at the origin, and the other approaching it with velocity v along the line x=b, y=0 where b=e^2/2 \pi \epsilon_0 mv^2. Find the scattering angle in the CM...

I was wondering if it is possible to image the motion of individual air molecules? What I am picturing is using a laser to illuminate a volume of air, and using scattered light to measure the velocity of individual air molecules through the doppler shift of the scattered light. It seems that...

Hi, I read in some papers which say the unit of atom scattering factor is e/atom. what is the meaning of that? thank you!

Homework Statement After undergoing through 90° compton scattering, the fraction of energy lost by photon is a) 10% b) 20% c) 50% d) zero e) none of these Homework Equations ∆λ= h/moc (1-cosΦ) The Attempt at a Solution What i m doing is that, i get scattered photon energy and subtracting...

According to Tong there are two Feynman diagrams for nucleon-nucleon scattering in the interaction of the complex and real scalar fields, but I can draw another diagram where the p1 and p2 particles enter a vertex and the p1' and p2' particles go out of another vertex (linked to the first one by...

Homework Statement A low-energy particle collides elastically with a stationary particle of the same mass. The angle between the subsequent paths of both particles are 90 degrees. But when a high-energy proton collides with a stationary proton, the angle between the two paths is not 90 degrees...

Homework Statement Onto an Aluminium 50μm thick plate, we send a beam of alpha particles with unknown kinetic energy. the cross section of the beam is 2cm2, density 1013 / scm2 . Whats the kinetic energy of the particles if every second we sense 105 scattered particles between the angles 40°...

From what I understand, a photon of "sufficient" energy will interact with a free electron such that the recoil electron receives part of the energy of the photon, and the scattered photon has a Doppler shift (change in wavelength). If the scattered photon still has "sufficient" energy, Compton...

In a typical collider experiment, two particles, generally in approximate momentum eigenstates at ##t=-\infty##, are collided with each other and we measure the probability of finding particular outgoing momentum eigenstates at ##t=\infty##. Firstly, what does it mean for the particles to be in...

Hello all, I'm just doing some practice for an upcoming exam and came upon this question in my notes: One experimental way to generate very high energy photons is to ”collide” a laser beam against an electron beam, the photons that recoil in the direction parallel to the electron beam will have...

Homework Statement A 0.7MeV (E°) photon scatters off a free electron such that the scattering angle of the photon is twice the scattering angle of the electron (θ=2φ). Determine the scattering angle for the electron. Homework Equations λ' - λ° = h/(mec)(1-cosθ) E = hc/λ ρelectron = mev /...

Homework Statement In a fixed target experiment a particle of mass M and kinetic energy T strikes a stationary particle of mass M. By evaluating s, t and u in the laboratory frame and using the above relation, or otherwise, show that the kinetic energy T' of the particle scattered elastically...

I'm trying to visualize the effect of the inverse square law, not on a direct source of light, but on scattered light carrying visual data, such as that responsible for our everyday sight of things as well as our images of Earth from satellites. It seems to me that it should be true that, while...

Hi, I really don't have a clue to solve this. I tried something like the dirac function identity: But then I saw it's dk' not dk' and couldn't got it straight. Can someone help me with this?

Homework Statement 1) Calculate the angular diameter distance to the last scattering surface in the following cosmological models: i) Open universe, ΩΛ= 0.65, Ωm = 0.30 ii) Closed universe, ΩΛ = 0.75, Ωm = 0.30 ii) Flat universe, ΩΛ = 0.75, Ωm = 0.25 Describe how the CMB power spectrum...

We know that the solution of the schroedinger equation for a free particle in position representation is a plane wave: \psi(x)=Ae^{ikx}+Be^{-ikx} which means that the particle has a probability to move either to the left or to the right. "Now let's take the potential step problem. V(x)=0 for...

Hello everyone, Still working on my reading of Weinberg's Lecture notes on QM book. At one point, the following integral $$\int d^3 xd^3 x' V(\vec{x~}) V(\vec{x'}) / |\vec{x~} - \vec{x'}|^2$$ has to be computed in the case where ##V(r) = -e^{-r/R}/r##. This reminds me of retarded potentials...

Homework Statement Show that the scatter angles of the photon (θ) and electron (Φ) in the Compton effect are related by the relation: ##cot (θ/2 )=(1+\frac{hf}{mοC^2}) tan(Φ) ## Where f is the frequency of incident photon 2. The attempt at a solution I wrote down the equations of conservation...

Let's say you have a monochromatic laser beam directed towards a light sensor. As you move the sensor away from the laser, the intensity read by the sensor will decrease because of scattering on air molecules (extinction). Since intensity is proportional to the square of the E-field amplitude of...

For particle physics research reference and education purposes, it's often convenient to have comprehensive particle scattering tables and Feynman diagrams at hand for analysis. May I ask whether there is a web site, app, or ebook that dynamically generates comprehensive scattering tables for...

What makes dispersion be different from scattering? What exactly is the definition of scattering? Google says it is to deflect or diffuse.how can deflection be a synonym for scattering? How are they related?

Homework Statement Photon of energy E=0,3MeV is scattering at an angle \phi=\frac{2\pi}{3}. Calculate the energy E' of scattered photon and emitted electron. Homework Equations -Compton effect The Attempt at a Solution By Compton effect...

I have a question about Thomson scattering from an electron hit by an incident em plane wave. The derivations that I have found all state the same thing. You have an electron in the origin at rest as the initial condition, the incident plane wave is linearly polarized towards z with amplitude...

Homework Statement I am trying to show that as the alpha particle is being scattered, the angular momentum magnitude at point M is m r^2 \frac{d \phi}{dt}. Diagram: Homework Equations Linear Momentum: ##\vec L = \vec r \times \vec p ## Repulsive Coulomb Force: ##\vec F = \frac{k 2Ze^2}{r^2}...

I'm studying dispersion relations applied as alternative method to perturbation theory from Weinberg's book (Vol.1) Let's consider the forward scattering in the lab frame of a massless boson of any spin on an arbitrary target ##\alpha## of mass ##m_\alpha>0## and ##\vec{p}_\alpha = 0##...

Homework Statement Calculate the cross section for the scattering of a 10 MeV alpha particle by a gold nucleus (Z=79, A=197) through an angle greater than a) 10 degrees b) 20 degrees c) 30 degrees. Neglect Nuclear recoil. Homework Equations...

Why do particles scatter in particle-particle collision while photons don't in photon-photon collisions, assuming that photons don't have enough energy to create particle anti-particle pairs?

I'm trying to figure our the relation between cross section, scattering angle and KE? I'm doing a few exercises where I've been given kientic energy and scattering angle and have to calculate the cross section. Cross section is in units of Barns (m2), and KE is 1/2 kg*m2*s-2, but I can't seem...

Homework Statement Carbon scatters on a proton. What is the limit of the angle of scattering? I'm not really sure where to start this question. I know it has something to do with Rutherford Scattering and impact parameter. Homework EquationsThe Attempt at a Solution

Hi. I've been reading about Compton scattering and I don't understand what determines the angle at which the electron and photon are scattered. Is it a quantum process, and therefore the value of the angle is "random"? If it is a quantum process, is there any theory that gives the probability...

Hallo. So the other day I reviewed a bit of quantum field theory and went through the Compton scattering calculation. To no ones surprise it was fairly simpel if you have a nice list of identities for rewriting the base results from the Feynman diagrams. See for exaxmple section 5.3 in...

Homework Statement The problem I have been set is to rework the Drude model using clearly defined scattering statistics. Homework Equations The Drude model as we have been given it is in terms of momentum \vec{p}(t+dt)=(1-\frac{dt}{\tau})(\vec{p}(t)-q\vec{E}(t)dt)+(\frac{dt}{\tau})(0) Where...

As I understand it, the 2-point fnuction is for 1 particle incoming, 1 particle outgoing. The 4-point function is for 2 particles incoming, 2 particles outgoing. Is this correct? So an N-point function describes N/2 incoming particles and N/2 outgoing particles? Thanks!

Consider a monoatomic 1-D chain of atoms (only acoustic branch). What happens with the inference of the dispersion curve through neutron scattering? In one dimension, conservation of momentum dictates $$ k'=k+K_s $$, if k_s is the phonon momentum vector and we only consider processes where a...

Homework Statement A beam of electrons with kinetic energy 50 eV is fired at a 100 nm thick crystalline nickel foil. (a) Calculate the speed of the electrons in the beam.(b) Based on your answer to part (a), state, with justification, whether classical (Newtonian) mechanics correctly...

Homework Statement Say there exists a delta potential V(x) = α(x-L). Solve the eigenvalue problem to yield the energy eigenstates. Say a quanton is in an initial state given by Ψ(x)=Aeikox at t=0. What is Ψ(x,t)? Homework Equations Schrodinger Eqn. The Attempt at a Solution I solved the first...

Homework Statement 2. The attempt at a solution I thought because they are negatively charged and so they will get attracted to the positive nucleus, and also because they are too small, but they are not acceptable. The answer is that they have a range of energies / they are deviated by...

Homework Statement Briefly describe how diffraction through a crystal lattice could be used to isolate a single wavelength from X-rays of many wavelengths. Homework Equations Bragg's equation: 2dsin(Θ)=n*λ The Attempt at a Solution Pretty fundamental question for the lab that I am about to...

it makes sense that with an inelastic scattering process, a wave approaches a crystal, and then some energy is imparted to the phonons, so that the outgoing wave has a different frequency from the incoming wave. However, with an elastic scattering process, the frequency is unchanged-- how does...

I have several questions about the scattering of light. Air molecules scatter sunlight and makes the sky blue, many books say that the air molecules are oscillated by E field and so they becomes sources of EM wave. Is it because the air molecules have charges? I wonder if air molecules or...

Hi all, I post a question about the dimension of wave function in position space before and people help me to identify that the unit of wave function should be in the unit of ##\text{m}^{-1/2}##. I am verifying that by doing the dimension analysis on Schrodinger equation...