Scattering is a general term for several physical processes in which radiation of some sort changes direction due to an interaction with a particle. Scattering can be classified by the type of radiation (ie, electromagnetic, x-ray, neutron), or by the relative sizes of the wave and the particle (ie, ...

learn more… | top users | synonyms

2
votes
1answer
359 views

How does physics scattering experiments relate to real life? And what does the scientist gain from such experiments?

How does physics scattering experiments relate to real life? And what does the scientist gain from such experiments? I am having a hard time figuring the answer out. Please help.
5
votes
3answers
646 views

Physical interpretation of infinite total cross section

What does it tell us about a process, say A+B->C+D, if the calculated total cross section is infinite?
2
votes
1answer
112 views

Cross sections and renormalization scheme

Can the result on cross section of some process be dependent on the renormalization scheme used?
15
votes
4answers
2k views

Tree level QFT and classical fields/particles

It is well known that scattering cross-sections computed at tree level correspond to cross-sections in the classical theory. For example the tree level cross-section for electron-electron scaterring ...
0
votes
1answer
461 views

Phase shift for Scattering in radial potentials

given a radial potential in 3 dimension and its Schroedinguer equation $ -D^{2}U(r) + \frac{l(l+1)}{r^{2}}+V(r) $ here D means derivative with respect to 'r' then if we apply quantum scattering how ...
0
votes
1answer
168 views

What is the dominant interaction in elastic collision pi- + neutron -> pi- + neutron?

What is the dominant interaction in elastic collision pi- + neutron -> pi- + neutron? Is it strong nuclear interaction or electromagnetism? Edit: sorry I meant to say "elastic". There is no matter - ...
2
votes
2answers
260 views

What is deep Fresnel region?

If I understand correctly, it has something to do with autocorrelation function, but can someone give me a definition or exact explanation? In case of scattering, if you wish to analyze pattern with ...
4
votes
0answers
597 views

Raman Scattering and the Kramers-Heisenberg Formula

Using the words of the wikipedia article Raman Scattering: The Raman effect corresponds, in perturbation theory, to the absorption and subsequent emission of a photon via an intermediate ...
5
votes
1answer
141 views

diffusion by an external potential in quantum field theory

I'm studying quantum field theory and I encountered some problems of diffusion of particles by an external potential. Until now I have to do with diffusion of the type particle-particle obtaining the ...
6
votes
1answer
685 views

What does the Rayleigh Phase Function tell us

I am working on some radiative transfer equations, and struggling as I'm fairly new to this field. I have read about the Rayleigh Phase Function which is: $P(\theta) = \frac{3}{4}(1 + cos^2 \theta)$ ...
18
votes
6answers
2k views

Why can we treat quantum scattering problems as time-independent?

From what I remember in my undergraduate quantum mechanics class, we treated scattering of non-relativistic particles from a static potential like this: Solve the time-independent Schrodinger ...
3
votes
1answer
2k views

What is the Jost function in scattering theory?

What is the Jost function in scattering theory? Is it an operator or some kind of determinant? How is it obtained?
2
votes
2answers
2k views

How do you calculate the intensity of light around the focal point from a focused collimated beam of light?

Problem/Purpose of me asking this question to you people who know more than me: So I'm doing a science project where I'm collimating a beam of light to a focus point in a light medium (water vapor or ...
19
votes
3answers
78k views

Why does the moon sometimes appear giant and a orange red color near the horizon?

I've read various ideas about why the moon looks larger on the horizon. The most reasonable one in my opinion is that it is due to how our brain calculates (perceives) distance, with objects high ...
6
votes
2answers
5k views

Scattering vs bound states

Why are these states called as such, and how do they differ? I vaguely understand that when $E > 0$ you obtain a scattering state, but when $E < 0$ you have a bound state.
6
votes
4answers
573 views

Far-field intensity from scattering of small particles

Howdy, I'm building a simulation for looking at the light field underwater. In order to verify my simulation, I'm looking for some data showing the far-field intensity that comes from single ...
14
votes
1answer
6k views

Phase shifts in scattering theory

I have been studying scattering theory in Sakurai's quantum mechanics. The phase shift in scattering theory has been a major conceptual and computational stumbling block for me. How (if at all) does ...
7
votes
1answer
329 views

How do ideas of leading singularities and Grassmanian help in curing infrared divergences when calculating N=4 scattering amplitudes?

Broadly speaking how do ideas of leading singularities and Grassmanian help in curing infrared divergences when calculating N=4 scattering amplitudes? My understanding is that one gets infra red ...
21
votes
2answers
735 views

Covariant Description of Light Scattering at a fastly rotating Cylinder

Let us consider the following Gedankenexperiment: A cylinder rotates symmetric around the $z$ axis with angular velocity $\Omega$ and a plane wave with $\mathbf{E}\text{, }\mathbf{B} \propto ...
10
votes
2answers
682 views

Calculation of the cross section

Why, when we calculate the total cross section, we make the average other initial states and the sum over final states?
1
vote
1answer
867 views

Electron/Photon Scattering

Hey guys, I have a final tomorrow and I am going over some assignments. One of the questions from the assignment was: A photon having 37 keV scatters from a free electron at rest. What is the ...
5
votes
1answer
858 views

What is the range of validity of Fermi's Golden Rule?

It is well known that to calculate the probability of transition in the scattering processes, as a first approximation, we use the Fermi golden rule. This rule is obtained considering the initial ...
39
votes
5answers
3k views

Scattering of light by light: experimental status

Scattering of light by light does not occur in the solutions of Maxwell's equations (since they are linear and EM waves obey superposition), but it is a prediction of QED (the most significant Feynman ...
4
votes
3answers
404 views

How do molecules vibrate after collision?

The difference between kinematics and dynamics that Grisha pointed to in his answer comes up in a similar but slightly more complicated case: Consider (in 1D) two point-like particles connected by a ...
1
vote
3answers
353 views

Where do atoms go after collision?

[I edited the question according to Mark's and Grisha's answers.] Consider two point-like particles of equal mass colliding centrally in 2D. The final directions of the momenta of the two particles ...
24
votes
4answers
2k views

Why does the sky change color?

Why the sky is blue during the day, red during sunrise/set and black during the night?