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.
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Simplifying some momentum and gamma matrices algebra in invariant amplitude calculation
I'm calculating some `$B_0 \rightarrow K^* \nu_R \nu_L$ decay and right now I'm stuck at invariant amplitude $\mathcal{M}$, which leads from the tensor part of Lagrangian. I'm having trouble ...
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Calculating Cross Section in terms of barns (help with converting from natural units)
I am trying to calculate the Glashow resonance to get something in terms of barns but I am getting confused switching between natural units and non-natural units. The Glashow Resonance is given by the ...
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Proving that the interference current integrated over a small cone does not depend on the angle of the cone
I'm studying quantum mechanical scattering and I have gotten to $$\psi=\psi_{in}+\psi_{scattering}=e^{ikrcos\theta}+f(\theta,\phi)\frac{e^{ikr}}{r}$$ and when calculating the current, i get three ...
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What exactly does the quantity $\sigma(\theta)$ represent in scattering problems? What is the interpretation of the differential cross section?
So I don’t understand intuitively what the scattering cross section is. The equation also seems quite random to me. I have looked at derivations but I cannot wrap my head around. I am looking for some ...
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Why differential scattering cross sectional area is same for Lab frame and centre of mass frame
Differential scattering cross section is denoted by:
$\frac{{d\sigma}}{{d\Omega}}$
Here, "$d\sigma$" represents the infinitesimal differential scattering cross-sectional area, which is not a ...
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How is it possible to collide particles with specific momentum in microscopic scale?
Quantum theory says particles with almost specific momentum are spatially spreaded. (have relatively large spatial scales). Then how is possible to collide them very effectively in microscopic scale? (...
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How is the Neutron capture cross section of Xenon-135 so high?
Xenon-135 has a Neutron capture cross section of 2-3 million barns, this is equivalent in area to a disk with a radius of 8-10pm. The cross sectional area of a Uranium nucleus is roughly 1 barn. The ...
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Where could I find an example of a numerical calculation in quantum electrodynamics?
I’ve been reading Student Friendly Quantum Field Theory and I’m discouraged by the fact that I’ve yet to encounter an actual numerical calculation in the book. I feel like I would be able to ...
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How can I calculate the reflectivity of an electron gas with Thomson scattering?
I have to do a seminar presentation about the topic of using relativistic mirrors in integrated laser ion accelerator systems.
The idea is (for context sake) to accelerate an electron bunch to ...
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Confusion about scattering in QFT
When it comes to scattering in QED it seems only scattering cross sections and decay rates are calculated. Why is that does anyone calculate the actual evolution of the fields themselves like how the ...
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How to get Absorption cross section of Gaseous Ions for photons?
How or where can I find the Absorption cross-section of Gaseous Ions? I have looked over the internet and can only find it for neutral atoms. Does it increase or decrease for ions?
I have found ...
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Cross-section of pair creation via vitual photons not positive definite
Consider the process of pair creation via two virtual photons, i.e. $\gamma^*(k_1)+\gamma^*(k_2) \rightarrow l^-(p_1)+l^+(p_2)$, where the dilepton (or any other fermions) can be massless or massive, ...
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Differential cross section of $\Phi^1\Phi^2\rightarrow \Phi^1\Phi^2$ process in linear sigma model: contribution due to forward scattering
In Peskin and Schroeder exc. 4.3 we are asked to compute the differential cross section of $\Phi^1\Phi^2\rightarrow \Phi^1\Phi^2$ process for the linear sigma model:
Compute, to leading order in $\...
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On the renormalization condition of the QED vertex function
In any renormalizable theory, we exploit the so-called renormalization conditions to determine the finite part of the counter-term couplings (namely $Z_1, Z_2$, etc in QED). In the on-shell scheme, we ...
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How Schwartz switch to the new variables in integration but left some of old variables untouched?
In Section 5.1.2 of Schwartz's when he changes variables from Equation 5.27 to Equation 5.29 he left a piece of old variables and treat it as constant. Shouldn't $p_f$ also be replaced with some ...
