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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What is the phase space for outgoing photons?
For a scattering process for which $n$ fermions are scattered, (by some conventions) the cross section acquires a phase space factor of:
$$d\sigma \sim \prod_{i=1}^n\frac{d^3p_i}{(2\pi)^3 2E_i}$$
In ...
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regarding vertex function and proton scattering
I am currently going through electromagnetic form factor. I came across the fact that since the proton is not an elementary particle its scattering(elastic) with electron can be modeled using general ...
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total cross section and contribution
Since in electron electron scattering if initial energy is quite large then muon antimuon production process can also take place which also contributes thus increases the total cross section.
What ...
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Different cross section for W and Z boson
At hadron colliders the cross section for W production is about ten times larger than the production cross section for Z bosons (e.g. Figure 2 in this review article). I guess the dominant ...
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Form Factor in Rutherford Scattering
My question relates to Rutherford Scattering of particles. When we calculate the "differential cross-section" expression for a nucleus with finite size, it is said that the expression is almost the ...
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Is the total cross section a Lorentz Invariant?
In Peskin and Schroeder's book (P&S), on the botton of page 106, the authors say that the total cross section transforms as its only non-invariant factor, namely:
$$
{1 \over E_{A} E_{B} |v_A - ...
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Why is number of collisions equal to number of scattered particles times number of scatterers?
In Landau, Lifshitz "The Classical Theory of Fields" $\S12$ "Invariant cross-section" the following is said1:
... according to the usual definition of the cross-section $\sigma$, the number of ...
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Understanding the concept of cross section
The cross section is a tiny area, measured in barns ($10^{-28} \mathrm{m^2}$), which relates to the probability of a reaction.
But I have trouble interpreting that number.
For example how can I ...
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Why are neutrino and antineutrino cross sections different?
Particularly in the case of Majorana neutrinos, it seems a little odd that the particle and antiparticle would have differing cross sections.
Perhaps the answer is in here, but I've missed it:
http://...
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From a cross section to a probability
This is homework problem:
Given the cross-section of a neutrino-electron scattering, what is the probability for a solar neutrino to scatter with a electron as it goes through the center of the Earth?
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How to sum over final, and average over initial color states?
Consider the $s$-channel mediated top quark production process
$$ d + \overline d \rightarrow t + \overline t$$
Using the Feynman rules for QCD, the amplitude contains a color factor
$$[c^\dagger _{\...
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Energy-dependent neutron cross section data
Where I can find a table with energy dependent cross sections for neutrons?
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Conversion of QCD cross section formula
I'm writing a program to calculate NLO cross sections for semi-inclusive high-$p_T$ pion production in proton-proton-collisions for my bachelor thesis.
I've got a paper describing the production ...
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The process $\mu^+\mu^-\rightarrow hh$
I am doing some calculations in the Standard Model. I have a question that seems rather simple but makes me think a lot. I want to compute the cross section of the following process at the leading ...
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Internuclear Binding Force: Experimental geometric detail
I am looking for the most precise currently available deuterium potential energy curve (generated purely by experimental data) on the nucleon-nucleon scale. This is crucial. I need a radial cross-...
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Do molecular bounded systems shield or reduce neutron cross-sections?
When talking about neutron cross-sections, literature is usually investigating isolated cases of Neutron + Atom. Here, the abundance of hydrogen is dominating neutron fluxes through material.
I ...
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Rutherford Experiment - practical and theoretical questions
I performed the Rutherford experiment the other day, using Au thin foil of $2\,\mathrm{\mu{}m}$, a source/gun of α particles (241Am) and a detector/counter. α particles were shot from the source ...
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How to prove the equivalence of two definitions of the scattering cross section?
I have noticed that there are two definitions of differential scattering cross section in non-relativistic quantum mechanics.
One of them is the most popular, particularly it is used in the QM book ...
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Cross Section Peskin vs Srednicki
in Peskin Schroeder after the derivation of the differential cross section there is a comment for the central mass system (CMS), which says:
In the special case, where all four particles have ...
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Do nuclear reaction cross sections depend on the angle between incident beam and target-crystal?
Shouldn't the absorption rate of a beam of particles strongly depend on the angle between the beam and the target material's crystal-axis (if the target material is a monocrystal)? At certain angles, ...
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List of cross sections? [duplicate]
Sometimes I need to look up a certain cross section, say the inclusive Z production cross section at $\sqrt{s}$ = 7 TeV. Is there a place where 'all the' cross sections are tabulated (...
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Parton Distribution Functions, average cross section of the nucleon
Say we are given the scattering cross section for neutrinos from $d$ and $\bar{u}$ quarks as $\frac{d\sigma^{d}}{dQ^2}=\frac{G_F^2}{\pi}$, $\frac{d\sigma^{\bar{u}}}{dQ^2}=\frac{G_F^2}{\pi} (1-y)^2$, ...
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Why is the total interaction cross section larger for incident particles with lower energy?
The cross section of a nuclear interaction is a measurement of the probability of that interaction occuring. These probabilities are typically presented in terms of barns ($10^{-28}$ m$^2$) as a ...
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QFT: differential cross section from center of mass to lab frame
I have the following process: two ingoing particles, a photon hitting a nucleus, and two outgoing particles, the nucleus and a pion. I have computed $|M|^2$ and the differential cross section in the ...
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Literature value of forward-backward asymmetry on the Z resonance?
I did a Standard Model calculation and I want to compare my answer to a measured value.
Does anyone know the literature value for the forward-backward asymmetry $\frac{\sigma_F - \sigma_B}{\sigma_F + ...
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Integral in Peskin and Schroeder
I'm having a bit of a slow day, and can't see how to do the following integral in Peskin and Schroeder (page 107 for anyone with the book). We've derived in the centre of mass frame the integral over ...
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SUSY, ways to boost Chargino/Neutralino production?
Does anybody know a good reference that works out the equations for the Chargino/Neutralino production cross section in SUSY? I'm trying to understand if there are any tricks for boosting the ...
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Definition of scattered particle?
Compare the number of scattered particles:
$N_s=Fa\int\sigma(\theta)d\Omega$
With the total number of incident particles:
$N_{in}=Fa$
Here, F is the flux of incoming beam, a the area. sigma the ...
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What is the spectrum of the Earth's albedo?
I was recently discussing climate change with a friend and was surprised (and embarrassed) to learn that the heat capacity of CO${}_2$ is not higher than that of nitrogen contrary to my assertions. ...
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How do particle scattering cross sections scale with energy in colliders?
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.)
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What statistical test should I use?
I have two differential cross sections $d\sigma_{1,2}/dM$ ($M$ is some invariant mass) corresponding to different hypothesis. What I want is to calculate how well the appropriate experiment would do ...
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Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$ $p$ + $e^{-}$?
Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$ $p$ + $e^{-}$ ?
PDG's cross-section data listing does not include it.
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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?
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Inelastic nucleon-nucleon cross section at LHC energies
I am trying to reproduce the number of participants $N_{part}$ in Pb-Pb Collisions at LHC using a Glauber Monte Carlo simulation, specifically aiming to reproduce the values given in Phys. Rev. Lett. ...
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Cross-section in relativistic limit: Fermi's golden rule still valid?
In order to calculate the cross-section of an interaction process the following formula is often used for first approximations:
$$
\sigma = \frac {2\pi} {\hbar\,v_i} \left| M_{fi}\right|^2\varrho\...
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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 ...
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estimating ion collisions from Vlasov equations
Suppose you have a distribution function $ f_{\alpha}( \vec{r} , \vec{p} , t)$ obtained from Vlasov equations for a certain $\alpha$ species, say some ions.
Is there a rigorous way (in the domain of ...
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Quantum Field Theory cross sections integrals
Where can I find some examples of cross sections calculations in QFT done step-by-step? Those integrals are a little horror. For example - a simple scalar+scalar -> scalar+scalar at the tree level in ...