Scattering Definition and 820 Threads

Homework Statement An object from space (like an asteroid) approaches Earth. A collision will occur if the scattering cross-section is less than π*Re2. If the distance of closest approach is much greater than Re, no collision would occur. Find an implicit expression for the cross-section in...

I am looking for a realistic explanation of the double-slit experiment in terms of wave packets (instead of stationary waves). First of all this results in using the scattering cross section, i.e. the probability current (not the density). Then, I guess, there is a kind of time average. So one...

Homework Statement a,b is constant and s is impact parameter, θ is scattering angle. i know that ψ in the picture is <ψ=(π-θ)/2> Homework Equations differential scattering crossection dσ/dΩ = (s/sinΘ) I ds/dθ I and σ(θ)=∫(dσ/dΩ)dΩ The Attempt at a Solution i guessed, first step is that...

Greetings, Here is my question: What is the difference between the labframe and the center of mass frame in QM scattering theory? Is it that in the labframe both particles are moving towards each other and in the center of mass frame one particle is static and a second one is moving towards the...

This isn't a homework problem. I am preparing for a particle physics exam and although I understand the theoretical side of field theory, I have little idea how to approach practical scattering questions like these. THE PROBLEM: Dark matter might be observed at the LHC with monojet and...

Why do we need the presence of an intense radiation in Inverse Raman Effect and Multi Photon Absorption?

Homework Statement A proton beam of energy E=7mpc2 is incident on a cylindrical volume (V=20 cm3) of liquid hydrogen (density ρ=0.071 g cm-3) at rest. The spot area of the beam is A=4 cm2 and the total cross section is σ=30 mb. What fraction of the protons entering the target will interact...

Hi guys, I was studying dynamic light scattering experiment and I had a problem! Here's the thing: I read that in case of weak coupling between x-rays and matter the whole system behaves as a linear system. I knew that linear systems respond to an input signal with an output that has the same...

1)So from my understanding, as long as ##E>0## you will have scattering states and these scattering states will always result in an imaginary ##\psi##, but bound states can also have an imaginary ##\psi##? Is this correct and or is there a better way of looking at this maybe more conceptually...

My question here involves Delbruck Scattering specifically but my curiosity is more general. Delbruck Scattering is the scattering of a photon off of the Coulomb field of a nucleus via the creation and annihilation of real and virtual electron-positron pairs. The process can occur at energies...

Homework Statement Nuclear fusion reactions at the center of the sun produce gamma - ray photons with energies of about 1 MeV (10^6 eV). By contrast, what we see emanating from the sun's surface are visible light photons with wavelengths of about 500nm. A simple model that explains this...

A photon with wavelength lambda = 0.1050 nm is incident on an electron that is initially at rest. If the photon scatters at an angle of 60.0 degrees from its original direction, what are the magnitude and direction of the linear momentum of the electron just after the collision with the photon...

It is very well known that the sky scattering of visible light decrease with the wavelength, it is bigger in the blue portion of the spectrum( the reason why the sky is blue ) and is lower on the red portion of the spectrum, this scattering is even lower on the infrared section and lower still...

Suppose that we have that: \mathcal{M} = c \bar{u}^{s'}(p') u^s(p) \bar{u}^{r'}(k') u^r(k) For a fermion fermion scattering: f(k,r)+ f(p,s) \rightarrow f(k',r')+ f(p',s') Now if I want to calculate the polarization summed and averaged squared amplitude: \frac{|c|^2}{4} \sum_{r,r',s,s'}...

I am reading the textbook by Ryden and I just ran into a statement that puzzles me (on page 201 if you have it at hand): "For instance, we found that, in the absence of inflation, the horizon size at the time of last scattering was ##d_{\rm hor}(t_{\rm ls}) \approx 0.4\,\rm Mpc##. Given a...

Hi everyone, Could someone please offer a clear explanation of how electron scattering can be used to provide evidence for the existence of quarks? Thank you!

I am a graduate student and I am thinking of doing a project on "Inelastic neutron scattering and density functional theory". Can you please inform me what are the exact background knowledge(courses) I should have to.

Dear PF: I'm currently working in a problem that has had me stranded for several weeks now. The problem reads as follows: (See attachment) Consider a beam of quantum particles (that is, the particles are small enough to exhibit non-negligible quantum effects) that propagates through a...

I have some confusion about multiple scattering. We always say that the problem of single scattering is always deterministic in nature.But while modeling the problem of multiple scattering, we take that the problem is stochastic in nature. I don't understand why. Why multiple...

I'm having difficulties understanding the role of scattering on phase coherence in the Aharonov Bohm Effect. In particular I am trying to reconcile the following points: Inelastic scattering destroys phase coherence and prevents us to see the Aharonov Bohm Effect. Elastic scattering does...

I hope that this will be a simple question, but I had difficulty finding an answer by searching. If the Cosmic Microwave Background radiation was radiated over 13 billion years ago, and we are able to see it now, then does this mean that the radius of the universe at that time must have been...

Homework Statement We have a double step potential described by -V0 for |x| < a/2 0 otherwise. That is, three regions separated at -a/2 and a/2 with 0, -V0 and 0 We have a particle coming from the left with E > 0. Find the transmission amplitude S(E) Homework Equations...

I have seen many 'photoelectric effect vs compton effect' Questions in this and other forums, but i am still not convinced. I can see how photoelectric effect points to the particle nature of light. But i don't see how compton effect as a separate experiment is needed to confirm this. The only...

Dear PF, although I've gone through many particle phyics lectures and textbooks, I still have problems with wrap my mind around the whole scattering theory and cross section topics. 1. Is there a deep reason why cross sections for charged, point-like particles decrease with the center-of-mass...

The question is this: When a photon bounces off an electron, it gives some of its energy to the electron. The photon has no mass, however, and it must continue to travel at speed c. How is its reduced energy manifested? Now, I do somewhat understand what the Compton effect is and I read in my...

Homework Statement Every second ##N_{Li}=2\cdot 10^8## atoms of ##_3^7Li## with kinetic energy ##30 MeV## is Coulomb scattering on ##_{26}^{56}Fe## plate ##d_{Fe}=0.3mm## thick with density ##\rho =7800kg/m^3##. Under angle of ##30^°## and ##r=0.2m## away from the plate we have a target with...

I need a little more explanation about the solution discussed in the following thread. https://www.physicsforums.com/showthread.php?t=410830 Do I've to lookup for orthogonal functions? PS. required thread is closed so I'm posting here.

Hi thanks for reading. Is it possible to derive an explicit formula for the neutron scattering cross section as a function of energy and angle of incident and scattered neutrons respectively? This is for a (n,p) elastic collision with H-1 as the target.

Homework Statement A 2 mm thick plate of natural Silver absorbs 11% of neutron flux with kinetic energy 1 eV. What is the total scattering cross section for neutrons? ##\rho (Ag)=10500 kg/m^3## and ##M(Ag)=107.9kg/kmol## What is the ratio between the calculated cross section and geometric cross...

p + n -> p + n + ∏^- check charge conservation: + 1 + 0 = +1 + 0 -1 it doesn't equal so it wouldn't be possible? please could someone suggest why this is, or if I'm doing something wrong? thanks in advance. edit is it because the pion is the force carrier therefore should not be...

I am trying to follow a Maxwell's equations derivation for light scattering but don't understand 'why' the authors do the steps they do at this start bit. Help would be greatly appreciated... It starts with the incident electric field equation. \textbf{E}_{0}(\textbf{r},t) = \textbf{E}_0...

Hi, My textbook describes Compton scattering the following way: "...an x-ray photon...has a collision with a slow moving electron...the photon transfers energy and momentum to the electron [and recoils]..." Is it not true that by definition when a photon collides with a particle it...

Homework Statement Using the Eikonal approximation (1) Determine the expression for the total scattering cross section of a particle in a potential V(r) (2) Using this result, compute the total scattered cross section for the following potential. V(r)= \begin{cases} V_0, \text{for } r < a \\...

According to http://en.wikipedia.org/wiki/Delbr%C3%BCck_scattering " ... based on the relativistic quantum mechanics of Dirac according to which the QED vacuum is filled with ... electron-positron pairs ...[which] should be capable of producing coherent-elastic photon scattering..." If...

I'm writing a program for simulating the angle distribution of scattered particles from a gold nucleus but I doubt the results. I don't know...But it would be very good if someone check it and give some hints. I also want to ask should I vary both initial speed and impact parameter in one...

Homework Statement Two laser beams, one of wavelength 633 nm and intensity I1 = 4.00x106 W/m2 with a circular beam profile D1 = 1.33 mm in diameter, and one of wavelength 442 nm and intensity I2 = 4.00x106 W/m2 with the same circular beam profile are fired, crossing at an angle of θ = 45°...

hello, reading about the theoretical background of optical trapping. I was wondering how the scattering force originates. Often it is written, that the scattering force is due to reflection, but also the central rays refracted by a dielectric object should contribute ? So the scattering force...

If a photon collides with an electron not moving, and you know the momentum of the photon before and after, and the electrons momentum, is it possible to know the direction of the electron and the photon after the collision?

Hi all Can someone please describe how the form factor used in Rutherford scattering is applicable to neutron probing of nuclei? Also, is the kinetic energy required to probe a given radius simply given by the de Broglie wavelength where momentum, p >= h-bar / Radius ? (Relativity...

Hi, I am self-teaching Quantum Elctrodynamics, and have come across something which I do not understand. I would appreciate feedback from anyone on this specific issue from Atchison & Hey, "Guage Theories in Particle Physics" pg 238-239: In calculating the u-channel electron-muon...

are there examples in non-relativistic scattering off a central potential where the S-matrix can be calculated exactly? Thanks!

I have the following homework question I am working on. I am given three scattering angles: 42.8, 73.2, 89. (in degrees) without the wavelength of the light used. I am to show that these are consistent with a diamond lattice. I started with Laue's Law: delta(k) = G and according to the...

Homework Statement To study the structure of the lead nucleus, electrons are fired at a lead target. Some of the electrons actually enter the nuclei of the target, and the deflection of these electrons is measured. The deflection is caused by the charge of the nucleus, which is distributed...

I have to write some training on the following and I really have no idea. Is this correct? Any help is greatly appreciated;) Inelastic scattering In inelastic scattering, a neutron collides with and is temporarily absorbed by the nucleus of the target particle. This excites the nucleus...

If we were to scatter high energy (say E>>m_e) electrons off each other is there a hand wavy argument to come up with a rough estimate for the ratio of inelastic to elastic cross-sections? Would the dominate inelastic collision between two high energy electrons result in a single photon...

Hello everyone I need some one once and for all to give me the steps to have a clear step by step idea about the stimulated Brillouin scattering inside an optical fiber please and thank you

I've been reading Kittel's book on Solid state physics and while it's been mostly smooth sailing, the abrupt loss of rigour in places in unsettling. In particular, the bits about scattering seem to be just thrown in here and there without any rigourous mathematical treatment at all. He talks...

Homework Statement Prove the relationship between the momentum of the neutrino or nucleon in an elastic scattering of them in the center of mass frame is p'^{2}=m_{1}E_{2}/2, where p' is the momentum of the neutrino or nucleon in the center of mass frame, m_{1} is the mass of the nucleon...

Consider a photon which is scattered by a crystal elastically. In an elastic scattering we have |k_i|=|k_f| and k_f - k_i = G where G is a reciprocal vector. But according to momentum conservation, the crystal must obtain a momentum \hbar G and hence the kinetic energy, so according...

For a double well consider an incident wave from the left. The wave gets transmitted and reflected at first well. The transmitted wave then hits the second well where it also gets both reflected and transmitted. The reflected part then hits the first well where it reflects and hits the second...