Scattering Definition and 919 Threads

I'm preparing for an exam and I expect this or a similar question to be on it, but I'm running into problems with using the Born approximation and optical theorem for scattering off of a finite well. 1. Homework Statement Calculate the cross sectional area σ for low energy scattering off of a...

Dear Community, I am trying to figure out what is happening in this article (https://journals.aps.org/prb/abstract/10.1103/PhysRevB.29.130) when they are calculating the Fredholm Determinant (Section IV). The basic idea is that you want to solve $$ k = |\frac{det(1+h_0)}{det'(1+h_0+v)}| $$...

I'm already aware that deep inelastic scattering, when an electron of high energy is scattered from a proton, shows us that the proton consists of point-like particles (quarks). However, what does elastic electron proton scattering tell us about the proton? Presumably elastic proton scattering...

Homework Statement Consider interactions of a X-ray beam at a depth, x, within a material. The flux density is: density flux = $$\frac{I}{A}$$ where I is the intensity of the beam that cross a unit area A at right angles to the beam. Let dx be a small slice at the depth x and let dI(x) be the...

I had learned that at the interface between 2 regions such as vacuum and a material, if there's an incident light from a region to another, the boundary conditions on the ##\vec E## and ##\vec B## fields at the interface are such that for them to hold at all times, the frequency of the incident...

Given a two particle scattering problem with (initial) relative velocity $|\vec{v}|$, apparently the product $E_{1}$E_{2}|\mathb{v}|$ can be expressed in the covariant form: $$ E_{1}E_{2}|\vec{v}| = \sqrt{ (p_{1}\cdot p_{2} - m_{1}^{2}m_{2}^{2}} $$ My textbook gives no further explanation -...

Homework Statement A triangular lattice of lattice spacing ##a=2 ## angstroms is irradiated with x-rays at time zero of wavelength 20 angstroms at an incident angle of ##\alpha =135##. 1) What is the maximum wavelength of the incident x-rays? 2) What is the scattering angle ##\Omega## for...

This thread refers to a paper I am working on. The paper said in the model section that: In the complete set of scattering states we distinguish two orthogonal set of eigenfunctions: (i) the states − → ϕ incoming from the left, and (ii) the states ←− ϕ incoming from the right. Away from...

Homework Statement Considering 2 scattering particles with momenta ##p_{1}, p_{2}##, where ##p_{2} = 0## in the Lab reference. The momenta of these 2 particles after elastic collision are ##p_{1}', p_{2}'##, respectively. Due to the 4-momentum relation, we have ##p_{1i}p_{1}^{'i} = e_{1}e_{1}'...

Hi, My question basically comes from this book called "Deep inelastic scattering" In the second chapter, it first made a similar argument for J = 1 Jz = -1, +1 which is pretty easy to get along with. However, immediately following from that there was this argument which confuses me a bit...

:smile::smile::smile::smile:Have you ever observe in night a source ( spherical) emitting light in strange fashion. If not then observe today. I saw that it was more towards the corner making plus sign or cross sign which can be seen through our eyes . Is there is something which is attracting...

Homework Statement In the inverse Compton scattering there is a particle, with energy ##E## in the laboratory frame and mass at rest ##m##, which collide head on with a photon with energy ##E_\gamma##. Finding the maximum energy the photon can have after being scattered. The Attempt at a...

Homework Statement Finding the maximum scattering angle of a particle whose mass in ##m_1## which hits with relativistic velocity ##v## a particle at rest with mass ##m_2<m_1##. The Attempt at a Solution I've written the 4-momenta (p before the collision, k after the collision and the z-axis...

Hello, I am having a bit of trouble understanding the concept of Rayleigh scattering as it relates to light from the sun. My book states that unpolarized light will hit the atmosphere, and the scattered light will be mainly horizontally polarized, while the unscattered light remains...

Homework Statement In a Compton scattering experiment, an x-ray photon scatters through an angle of 17.40 from a free electron that is initially at rest. The electron recoils with a speed of 2180 km/s. Calculate (a) the wavelength of the incident photon and (b) the angle through which the...

Homework Statement A beam of spin-1/2 particles scatters off of a target consisting of spin-1/2 heavy nuclei. The interaction between the particle and nucleus is given by $$V(\vec{ r})= V_0~\delta (\vec{r})~ \vec{S}_1. \vec{S}_2$$ 1) Averaging over initial spin states, find the differential...

Homework Statement Homework EquationsThe Attempt at a Solution ## \lambda' = 2 \lambda ## ## \lambda' - \lambda = \lambda = \frac { h} { mc} \cos{ \phi } ## Here, ## \phi = \frac { pi} 4 ## is the angle between photon's original line of motion and its line of motion after...

I'm afraid this question is going to be a bit hand-wavy, but I'm hoping for a way of thinking about two-photon scattering that would be helpful to a beginner but also give correct results. The starting point is that, for two photons in SPDC and other similar cases, the phase difference is a...

Hi, I am quite confused about followed question, I think scientist think the last scattering surface was dense plasma at the temperature of 3000K. If the today's universe much cooler and less dense then "the last scattering surface" how can anyone says entropy increased by time? Isn't universe...

Homework Statement Consider the scattering of a scalar electron and a spin half muon, draw and label the feynman diagram for this process. write down the invariant amplitude M and the spin average |M|^2, use the trace notation.Homework Equations Photon propagator $$\dfrac...

Homework Statement (x^2 + y^2)/a^2 + z^2/c^2 = 1 Homework Equations [/B] The Attempt at a Solution the answer is : b(θ) = R / (f^2 * tan^2(θ/2) + 1)^0.5 I can't understand how to calculate this. My attempt : (x^2 + y^2)/a^2 + z^2/c^2 = 1 from this. b^2 + z^2/f^2 = a^2 , f = c/a, z =...

The Compton equation determines the shift of the wave-length of the scattered photon as a function of the ##cos\theta## of the scattered photon. It does not depend on the energy of the incident photon. With some manipulation using the equations of conservation of the momentum and energy, one...

Homework Statement For the following theory: ##\mathcal{L}=\frac{1}{2}[(\partial \phi)^2-m^2\phi^2+(\partial\Phi)^2-M^2\Phi^2]+g\phi^2 \Phi^2## Compute s-channel amplitude for process ##\phi\phi \rightarrow \phi\phi##. Interpret result for ##M>2m##. Homework Equations Scattering amplitude...

Homework Statement So I recently carried out an experiment for Rutherford scattering. From my lab script is states the following 'Recording the scattering rate as function of angle In order to compare your results with “Rutherford’s scattering formula”, you must first make a correction for the...

Given that the Hamiltonian is H = P^2/(2m) + aδ(X − x(naught)) + bδ(X + x(naught), where x(naught) is a positive number. Find the conditions for bound states to exist and calculate their energies. Find the scattering matrix for arbitrary values of a and b. Can someone help me solve this please.

Homework Statement Suppose we have a potential such that $$ V = \left\{ \! \begin{aligned} 0 & \text{ if } x<0\\ \mathcal{E}x & \text{ if } x>0, x<L\\ \mathcal{E}L & \text{ if } x>L \end{aligned} \right. $$ for some electric field ##\mathcal{E}##. I'm trying to find the transmission...

I recently read this article from Science Alert regarding Light by Light Scattering (http://www.sciencealert.com/light-continues-to-behave-really-weirdly-in-the-large-hadron-collider). They seemed to be astonished to witness light actually bouncing off each other, as they state that photons pass...

Hi. My question is about nucleon-nucleon scattering. In David Tong's lecture note, he discusses Wick's theorem and nucleon scattering (page 58-60). My problem is that I don't know how to calculate the second line of eq(3.48): \begin{equation} <p'_1, p'_2|:\psi^\dagger (x_1) \psi (x_1)...

Rayleigh scattering is what caused the sky to be blue.. what elements must be replaced to make the sky orange, or yellow or other colors? Is there a list of elements somewhere for the different colors?

Homework Statement A high-energy photon collides with a proton at rest. A neutral pi meson is produced according to the reaction ##\gamma + p \to p + \pi^{0}##. What is the minimum energy the photon must have for this reaction to occur? (The rest mass of a proton is ##938\ \text{MeV/c}^{2}##...

Homework Statement In a 2-body scattering event, A + B → C + D, it is convenient to introduce the Mandelstam variables, s ≡ −(PA + PB)2 , t ≡ −(PA − PC) 2 , u ≡ −(PA − PD) 2 , where PA,...,D are the 4-momenta of the particles A, . . . , D respectively, (· · ·) 2 = (· · ·) · (· · ·) denotes a...

Homework Statement Compton scattering can be used both to measure the direction and energy of photons in nuclear physics experiments. For a particular preparation a spectrum of Compton scattered electrons was measured which clearly corresponded to a generally monochromatic gamma radiation. The...

Homework Statement Why does Thomson scattering occur in the early universe? Homework Equations $$ e^{-} + \gamma \rightarrow e^{-} + \gamma $$ is a Thomson scattering process if: $$ E_{\gamma} << m_{e}c^{2}$$ (Electrons are essenitally stationary) The Attempt at a Solution [/B] Very confused...

Homework Statement Consider two real scalar fields \phi,\psi with masses m and \mu respectively interacting via the Hamiltonian \mathcal{H}_{\mathrm{int}}(x)=\dfrac{\lambda}{4}\phi^2(x)\psi^2(x). Using the definition of the S-matrix and Wick's contraction find the O(\lambda) contribution to...

Homework Statement Hello, everyone . My teacher has given me an assignment to show that the exact Coulomb amplitude (2) satisfies the unitary condition for an elastic Scattering theory (1). (1) ## Imf(k',k'')=( \frac {κ} {4\pi} ) ∫ f^*(k',k'')f(k',k'')dΩ ## (2) ## f(θ)= \frac {-α} {2mϑ^2}...

Isn't Inverse Compton scattering just the Doppler's effect? A fast moving electron gets slowed down by a photon. This photon then becomes blue shifted, becoming a gamma ray. Kinda makes sense.

Homework Statement Consider Compton scattering of a photon by a moving electron. Before the collision the photon has wavelength λ and is moving in the +x-direction, and the electron is moving in the −x-direction with total energy E (including its rest energy mc2). The photon and the electron...

I read from a text that Rutherford found out that all the mass must be concentrated in the middle of the atom due to fast-moving alpa ( high momentum) is deflected back at 180 degrees. I am wondering if there is going to be no contact collision due to the the kinetic energy being converted...

Consider the scattering process ##W^{+}W^{-} \to W^{+}W^{-}##. This process is mediated in the Standard Model by 1. a four-##W## scattering, 2. ##Z##-boson exchange, 3. Higgs exchange...

Can someone explain this paragraph especially the bold part in simpler language: "If it is not in a major crystal direction or plane ("random direction", Fig. 2), it is much more likely to undergo large-angle scattering and hence its final mean penetration depth is likely to be shorter." full...

This question is as dumb and simple as it can be: Why is the path difference 2dsinθ? Or better said: Why x-ray scatters like in the image? (Couldn't there be another scattering angle for both atoms other than θ?)

Hello, I'm wondering how you would go about drawing a Feynman diagram for a weak charged current scattering interaction of a positron and a proton. I have attached a diagram of what I have tried but it doesn't conserve lepton number (I think this is a problem, from what I gather...

Homework Statement In an experiment carried out with a beam of thermal neutrons it is found that on traversing a 2mm thick foil of 197Au, some 70% of the neutrons are removed. What is the total thermal neutron cross-section for this isotope of gold? Comment on the result of the cross-section...

Homework Statement A photon with wavelength 0.1385 nm scatters from an electron that is initially at rest. What must be the angle between the direction of propagation of the incident and scattered photons if the speed of the electron immediately after the collision is 9.30×106 m/s? Homework...

Homework Statement A beam of thermal neutrons (K = 0.025 eV) scatters from a crystal with interatomic spacing 0.45 nm. What is the φ angle of the first order Bragg peak? (as defined in figure 5.11, φ and the scattering angle add up to 180 degrees). Homework Equations nλ = 2dsinθ = DsinΦ d...

I would like to draw the one-loop diagrams for four photon Delbruck scattering amplitude in QED. Here are the three one-loop diagrams that contribute to the scattering amplitude. There are three more one-loop diagrams that contribute to the amplitude. However, I cannot find the other...

During the photoelectric process, photons are absorbed and electrons are ejected. In Compton scattering, photons are scattered rather than absorbed. My textbook (Quantum Physics of Atoms,Molecules,Solids,Nuclei, and Particles) explains that absorption occurs in the photoelectric process because...

Hi, There's a pic on wiki page (Feynman type) showing deep inelastic scattering where a fast lepton interacts with a quark in a baryon by a virtual photon (clearly that doesn't change particle type) then there's an arrow labelled X that I guess is maybe a stream of other hadrons (mesons mostly I...

Is it possible to compute scattering amplitudes of a graviton interaction taking Einstein gravity as an effective field theory at low energies? I did not study qft the proper way yet, so any clarifications on the subject would be welcome.

Hi, I read that scattering is just hitting a particle and bouncing off at some other direction. But I also read that scattering involves the complete absorption and emission of a particle/wave. Is this part correct? I have been unable to find that bit of information anywhere else.