Scattering Definition and 919 Threads

How do particle scattering cross sections scale with energy in colliders? Particularly photons, electrons, protons, and gold or lead nucleii? (If necessary, break this into four separate questions.) It is stated that due to the Heisenberg uncertainty principle, it takes more energy to...

Hello, not sure if I'm typing the question in the right place, but I encountered this question when going through Peskin (eq. 6.44, though it's not important). If p and p' are respectively the momentum of electron before and after the scattering, then q=p'-p is the momentum of photon joining...

Hi, I'm reading Appendix 1 of Section N2 (Gluon Scattering) in "Quantum Field Theory in a Nutshell" by Anthony Zee. The generators for SU(N) have the usual algebra [T^a, T^b] = i \epsilon^{a b c}T^c Suppose we adopt the following normalization \text{tr}(T^a T^b) = \frac{1}{2}\delta^{a b}...

Hi all, I'm working on a problem about neutrino-electron scattering $$\overline\nu_ee^-\to e^-\overline\nu_e.$$ The problem says to prove that the maximum angle of emission for the recoil electron relative to the neutrino beam is $$\sqrt{{2m\over E}},$$ but I have worked on this for hours and...

I'm just wondering what the difference is between a cross section and a scattering cross section? Or is there any? I can't seem to find anywhere that clears it up, in fact there's a whole section on scattering cross sections in Kibble and Berkshire but they don't define it once :P

Hi, I'm a EE PhD student working a little bit out of my area, and have just gotten stumped trying to figure out the transient dymanics of a relativistic electron moving past a discontinuity. My little thought problem came up from wakefield interactions of a relativistic electron in a waveguide...

Homework Statement How much will the wavelength of the incident X-ray photon change by if it is scattered by 30 degrees when it interacts with an electron? Homework Equations This is Compton scattering. This is the equation I used: lambda ' - lambda (0) = (h)/(m(e)c) (1-cos...

Hi, I am trying to get a better understanding of what aspects of an electron-positron collision can be physically observed as opposed to mathematically inferred. In part, my confusion is based on a number of different sources, e.g. see links below, which seem to adopt different approaches to...

assume that a photon scattered by an electron initially at rest. which photon scattering angle corresponding to the largest compton shift and why? At what minimum photon energy can half of the photon energy be transferred onto the electron ??

Homework Statement True/False: Because the potential between an electron and positron is identical to that of an electron and proton, if we compensate for the difference in mass, the differential scattering cross section in electron-proton scattering must be the same as for electron-positron...

[b]1. The problem statement, all variables and given/known A general one dimensional scattering problem could be characterized by an (arbitrary) potential V (x) which is localized by the requirement that V (x) = 0 for |x|> a. Assume that the wave-function is ψ (x) =  Ae^(ikx) + Be^(-ikx)...

Homework Statement What is the maximum kinetic energy of electrons knocked out of a thin copper foil by Compston scattering of an incident beam of 17.5 KeV rays? Assume the work function is negligible. Homework Equations Δλ = h/mc (1-cosθ) The Attempt at a Solution I reasoned...

Hello everyone, I have a few questions regarding the principles behind XRF spec, as most of the sources I've consulted either don't go into enough detail and miss bits out (undergrad textbooks), or are simply beyond my current level of understanding (QM papers etc). When, for example, a...

Hi Everyone, :shy: I read in some paper about the significance of Graviton-Graviton Scattering as a theoretical tool in Quantum Theory of Gravity. Would someone bother to explain in detail what phenomena it is and how it is useful in Quantum Theory of Gravity.:confused: And I might not have...

This is something that I always just took for granted, but I have no idea how a photon scatters off of an electron at an angle other than 0 or 180 degrees. I haven't seen this mentioned in a modern physics or nuclear engineering textbook either, so I assuming its a pretty complicated reason?

Homework Statement Hello, I need to find which values for θ and ψ are not defined for the Compton scattering. Where θ is the angle of the electron and ψ is the angle for the photon.Homework Equations I have attached the formulas I´m using. http://tinypic.com/view.php?pic=v4z2qf&s=5The Attempt...

A particle of energy E is incident from the left on a potential step. If the energy of the particle is greater than the height of the step, it is acceptable to discard: Fe^{-ikx} saying that there is nothing incident from the right. If E is less than the step, it is not acceptable to...

I'm numerically evaluating the differential cross sections \frac{\operatorname{d}\sigma}{\operatorname{d} \Omega} for e^{-}e^{+}\rightarrow\mu^{-}\mu^{+} scattering by integrating over \operatorname{d}\Omega = \operatorname{d}(\cos{\vartheta})\operatorname{d} \phi. Assuming no transverse...

So compton scattering is where x-rays (or gamma rays) collide with an electron and sends it flying. In the process, the incident photon loses energy and is converted to a lower wavelength. According to wikipedia, Rayleigh scattering is the scattering of photons by particles which are much...

Homework Statement Hey I am revising for my physics test and am having a bit of trouble understanding rutherford's alpha scattering experiment. My teacher gave us a powerpoint but it does not seem to help me, more so it confuses me. I am a good physics student and not understanding this is...

hi, so i have just finished reading my first ever book on quantum electro-dynamics (the feynmann lectures). i am in year 13 of school, or High school some might call it. he draws a diagram in the book (a space time diagram) to represent an electron absorbing a photon and then re-emitting...

Hello there, I am reading this article: http://nis-lab.is.s.u-tokyo.ac.jp/~nis/cdrom/sig93_nis.pdf After chapter 4.2, it mentions some equations for approximating Rayleigh scattering. That is all well, however, it doesn't mention which units of measurement I should use, nor the value of...

Homework Statement Calculate the angular size of the comoving horizon at the z=1100 last scattering surface, as projected on to the current (CMB) sky. Assume flat FRW cosmology and no cosmological constant. First calculate angular diameter distance to last scattering, then the particle...

I am new to nuclear engg., i want to know the phenomenon of elastic scattering of neutrons. Resources available in the net suggest that in materials containing atoms of low atomic mass(hydrogen), neutrons of all energies can lose a significant fraction of their energy in a single elastic...

Hi. First of all, this question seems a bit obscure to me (like there are data missing) However, I quote it as it appeared in the source, so probably there aren't. Second, it is a question from a previous exam, so it is not graded or anything, and there is no problem helping me solving...

Just read Feynmen's QFT and been wondering the difference between photon reflection by a perfect mirror and photon scatter by say a rough surface. In both cases, photons are said to be absorbed by electrons and re-emitted. But in reflection case, photons get to "preserve" its wave...

Hi Guys, I'm doing a practice exam paper and I stumbled upon a question I can't answer for 5 marks. Describe the advantages of electron scattering over alpha particle scattering. Sketch a graph of charge density vs distance from centre of nucleus. From the graph, explain why protons are...

Hi, I need help with following problem: I need to solve scattering of the planewave incident on the metal wedge. Let's say that wave travels in $z$ direction. Angle of wedge is $\alpha$, it is formed in $x-z$ plane. Wedge is infinite in $y$ direction (metal corner, if $\alpha = \pi / 2$, it will...

Homework Statement We were asked to derive the Mott's scattering cross section. Given by \sigma(\theta)=(\frac{1}{4k^{4}}) (\frac{1}{(\sin\frac{\theta}{2})^{4}} - \frac{1}{(\cos\frac{\theta}{2})^{4}}\cos[\frac{2}{k}\ln(\cot\frac{\theta}{2})]) I get it into this form (that was easy, lengthy...

Is there a fundamental difference between specular and diffuse reflection, or between diffuse reflection and scattering? I have heard various explanations that I am trying to sort out. (Please note that these "explanations" are not necessarily an accurate record of what was presented to me--...

Homework Statement Homework Equations T=2*(m*M/(m+M)^2)*E(initial)*(1-cos(angle)), T is transferred energy from the neutron to the target. displacement energy for Zr=40eV The Attempt at a Solution the question is strange for me it seems to me there is a trick since we don't...

Homework Statement If the total energy of the electron E>>mc^{2} Prove that the formula of wavelength would be \lambda '=\frac{hc}{E}(1+\frac{m^{2}c^{4}\lambda}{4hcE}) where \lambda ' is the wavelenght after scattering m is the mass of electron Homework Equations The Attempt at a...

Rutherford scattering experiment question (urgent) Homework Statement I need to find the value of the electrical force between the alpha particle and the nucleus of the atom at the point of closest approach. Closest approach = 7.27 x 10^-14 m Charge on atom = (79 * 1.60 x 10 ^-19) C initial...

Incident Photon λ = 0.1050*10^-9 Angle which photon is scattered (θ) = 60° (relative to intiial direction) What angle is the electron scattered relaive to the original direction? (x) Okay, so using linear momentum conservation: (1) Incident photon momentum (p) = electron momentum (pe)...

why does conventional xray imaging utilise photoelectric effect but ct utilise compton scattering? i know that at different energies, different mechanisms (eg compton scattering, photoeletric effect, pair production) dominate but do they not chose the energy beam to correspond the process that...

Hello, I would really appreciate if someone explained to me how Rayleigh scattering works. I understand it as far as knowing that gas particles cause the shorter wavelength light (towards the violet part of the spectrum) to scatter more than the longer wavelength light. This apparently also...

Hello physicsforum, this is my first post I am reading up on scattering theory and I'm having difficulty rederiving some of the results. In 'Inverse problems in Quantum Scattering theory' (2nd Ed.) by Chadan and Sabatier they state that the solution for the s-wave regular solution, which is...

It is my understanding that electromagnetic radiation is absorbed by an electron and then emitted at another angle. So why does particle size affect scattering when the phenomenon involves electrons? Also, why does the size of the wavelength of the light relative to the diameter of the particle...

I do not understand the interpretation of the http://hyperphysics.phy-astr.gsu.edu/hbase/rutsca.html" . To me, that equation says: (1) for a given θ, the proportion of particles exiting at θ does NOT depend on mass or charge; (2) if you integrated over all possible scattering angles, you...

Homework Statement There is a constant potential, V0, in the region -a<x<a, -a<y<a, -b<z<b, and V=0 otherwise. Particles of mass m are incident on the scatterer with wave vector k in the x direction with a flux at the origin of one particle per second per cm^2. There is a detector with...

So I have become a bit confused by the relationship between intensity of Rayleigh scattering and density of the gas. Multiple sources (ex. Salby, Atmospheric Physics) give the scattering cross section per molecule, σ, to be dependent on 1/λ4, the index of refraction of the material and 1/N2...

Elastic and Inelastic neutrons scattering..! How I can find the energy lost by the neutron in elastic scattering and inelastic scattering, if we assumed its isotropic scattering in the center of mass?

Elastic and Inelastic neutrons scattering..! How I can find the energy lost by the neutron in elastic scattering and inelastic scattering, if we assumed its isotropic scattering in the center of mass?

I am interested in the use of carbon nanotubes for making transparent conductive films, for example to replace indium tin oxide. When I looked up papers on the subject, I noticed that most of the work to date has used single-walled carbon nanotubes. Initially I was under the impression that...

Currently, I am combating against the "Scattering theory" with J J Sakurai’s Textbook. The Lippman- Schwinger Equation, S matrix, T matrix, Optical Theorem,... But I find the explanation in Sakurai's book is not very clear or pedagogical. I want to find some easy-to-read references to have...

Homework Statement Red and green laser (wavelength of 650 nm and 532 nm respectively) are directed towards each other at 20 degrees. Each laser has 5 mW power, with diameter of 1mm. Assuming the intensity of the beams are decreased by 10% each after the 'collision', estimate the upper...

Homework Statement Spray of alpha particles hit a gold membrane whose density is \rho and thickness d, with a kinetic energy of E_k. The spray's intensity is I. Alpha particles are measured from an area of A which is set R away from the membrane. If \theta is the angle between the spray...

Homework Statement In a scattering experiment to measure the polarization of an elementary particle, a total of N = 1000 particles was scattered from a target. Of these, 670 were observed to scatter right and 330 to scatter left. Assume there is no uncertainty in N = Nr + Nl a) based on...

I am supposed to have a qualitive knowledge of acoustic peaks for my exam, so none of the maths. After reading around I am still left with a few questions. Is the first acoustic peak from the acoustic oscillations at last scattering? I imagine there were many oscillations before then but we...

Light is scattered many times by free electrons. The scattering goes on until the electrons freeze out, after 300,000 years. Can anybody explain this to me.