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Questions tagged [scattering-cross-section]

A cross-section is the name given to a hypothetical unit of area (often in units of Barns) for measuring the probability of scattering events in particles collisions. DO NOT USE THIS TAG for a physical non-probabilistic cross-section of a macroscopic object.

A cross-section is the name given to a hypothetical unit of area for measuring the probability of scattering events in particles collisions. See Beer-Lambert Law. should be used for questions about particle collision probabilities. DO NOT USE THIS TAG for a physical non-probabilistic cross-section of a macroscopic object.

522 questions
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Understanding scattering cross section

I think I might have a serious misunderstanding of some concepts to do with scattering cross sections and would really appreciate any help. As far as I can tell the differential cross section is basically a measure of what fraction of particles get…
plzhelp
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Cross section fon non-collinear beams

If I have two collinear beams with opposite velocities the cross section is defined by the formula: $\frac{dN}{dtdV}=\sigma \rho_1 \rho_2 |\underline{v}_1-\underline{v}_2|$ where $\sigma$ is the cross section, $\underline{v}_1$, $\underline{v}_2$…
Andy Bale
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Cross terms in scattering amplitudes

When computing tree level scattering cross sections, if there is for example a $t$ and $u$ channel diagram, then the scattering amplitude will look like $$\mathcal{M} = \mathcal{M}_t+\mathcal{M}_u.$$ When you take the magnitude, you get cross…
T-Ray
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Differential Cross Section

I would like to know what exactly the term differential cross section means. It comes from electron scattering experiments which are used to deduce the charge distribution of a nucleus and the cross section is given as a function of the scattering…
user1314
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Interpretation of total cross section in scattering

Based on my understanding, the differential cross section $\frac{d\sigma}{d\Omega}$ gives us the differential area of incident particles that projects onto a differential piece of solid angle on the detector. When one calculates total cross section,…
Jan Lynn
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Integrating the differential scattering cross section

In classical scattering theory, the differential scattering cross section, σ(Ω), is defined such that σ(Ω)dΩ is the number of particles scattered into the differential solid angle dΩ in the direction Ω per unit time, divided by the incident…
DaYu1729
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Why does cross-section decrease with density?

I read on the wikipedia page for cross-section, that cross-section is related to the reciprocal of a material's density. This seems entirely counter-intuitive. Is there an intuitive reason for this? Or am I misunderstanding this? From…
user97957
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Cumulative distribution function for Compton scattering

Just for reference, this is the cross section for Compton scattering. $$ \frac{d\sigma}{d\Omega} \propto\left(\frac{E'}{E}\right)^2\left(\frac{E'}{E}+\frac{E}{E'}-\sin^2\theta\right) $$ Currently I am integrating $d\sigma$ numerically to obtain…
ice9
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Coulomb excitation

I have read that a very large number of partial waves around 200 and a large matching radius of 300 fm is required to obtain the cross section in Coulomb excitation. This is certainly far greater than normally being used. Why are these values so…
SAKhan
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Data in elastic proton-proton scattering

Hello im trying to compute the cross section of an elastic proton proton scattering in the one boson exchange model and my results do not agree at all with experiment. I don't expect a excact fit since im working on only first approximation feynman…
Μπαμπης Ποζουκιδης
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The differential cross section and cross section

As we know the total cross section can always be obtained from the differential cross section: $$\sigma = \int_0 ^{2 \pi } \int_{0}^{\pi } \frac{d \sigma}{ d \Omega} d \Omega $$ I understand how the integration is done. For example, sometimes I see…
user12906
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Does scattering cross-section of a large number of scatterers tend to sum of their cross-sections?

Suppose we know differential cross-section for some type of scatterer particle. Now, consider a large number of such scatterers distributed randomly in some volume. If there's much space between these scatterers, I suppose the cross-sections of…
Ruslan
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How to integrate over a circle in sperical coordinates

I have an angular distribution $\frac{s \sigma}{d\Omega} = \frac{d\sigma}{d \left(\cos\theta\right) d\phi}$. How can I calculate it over a circle which lies on the plane $X = dist$, has radius $r$ and its centre is located at $P(a,b)$ on this…
user2738748
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Intuitive explanation of differential scattering cross-section

I'm looking for a conceptual, intuitive understanding of the differential cross section (classical scattering). Its origin, its use, the general process for derivation (conceptually, rather than the mathematical minutiae). Can anyone provide one?
DeltaG
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Why does the stimulated emission cross section decrease with the refractive index?

The stimulated emission cross section decreases with the refractive index. Cannot understand why ? Can anyone give a physical explanation ?
Anarchasis
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