Questions tagged [standard-model]
A model of the basic particles and forces featuring six quarks, three charged leptons, three massless neutral leptons and four fundamental force carrying bosons. The twelve fermions are arranged into three generations, while the bosons serve to explain the electromagnetic interaction plus the strong and weak nuclear forces (and the Higgs mechanism). Do NOT use this tag for the standard model of cosmology, etc..
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What will happen if we keep bringing two protons closer and closer to each other, starting from a large distance?
I am asking this question for theoretical understanding of the topic: What will happen if we keep bringing two protons closer and closer to each other, starting from a large distance?
I understand ...
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Doubt in $e^{+}e^{-}\rightarrow W^{+}W^{-}$ scattering
I am trying to understand how to compute the scattering amplitude for the process $e^{+}e^{-}\rightarrow W^{+}W^{-}$, as a reference one could look at Peskin chapter 21.
What I do not understand is ...
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Do GUT's really explain parity violation?
Every book on the Standard Model introduces early on the concept of left and right-handed quantum fields, defined as
\begin{align}
(\psi_L)_{\alpha} = \left(\frac{1-\gamma_5}{2}\right)_{\alpha \beta}\...
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How to be sure that when a muon passes a detector it is actually a muon?
The question is as follows: when you have any kind of detector for muons you just take measurements and you say, for example, the number for the muon flux but how you're sure that all particles ...
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Hierarchy Problem vs ratio of masses in the Standard Model
In the Standard Model, the ratio between the top quark's mass to the neutrinos is at least about $2 \times 10^{11}$. It could rise by at least an order of magnitude in the coming years as the ...
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The origin of the Hierarchy Problem
In the answer to this question on the origin of the hierarchy problem, it is stated that:
The low-energy parameters such as the LHC-measured Higgs mass 125 GeV are complicated functions of the more ...
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Where is antineutrino in standard model Lagrangian?
I'm somewhat confused by the content I studied in Srednicki's work, where the neutrino is described as a Majorana field. In this framework, there shouldn't technically be antineutrinos, given the ...
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One-Loop beta function for gauge couplings
I am currently doing my homework on Standard Model one-loop correction. When I am reading Quantum Field Theory by Mark Srednicki and Journeys Beyond the Standard Model by Pierre Ramond, I notice some ...
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Is there a Higgs-pole like the $Z$-pole?
Why isn’t there studies of direct Higgs production like for the $Z$ boson?
Looking for future colliders, they all aim for
$$e-e+ -> HZ $$
which for me makes sense for measuring a physical Higgs but ...
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Regarding vanishing of a triangle diagram
Furry's theorem ($C$ symmetry) is very important in calculations in QCD, Electroweak theory. Primarily it says everything about QED (three photon triangle diagram), but can be extended to QCD, and ($Z$...
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Evidence of more generations in the QCD beta function
We know that the beta function for QCD is
$$
\beta = -\left(11 - \dfrac{2N_f}{3}\right),
$$
where $N_f$ is the number of fermions in the theory. We have $\beta_{\text{SM}} = -7$.
Now, my question is, ...
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Is the set of possible elementary particle types equal to the set of all combinations of their properties? [closed]
I'm playing around with a mnemonic system for a fantasy language I'm working on, for remembering the properties of elementary particles. Each letter represents a unique sound.
i
a
u
These 3 are the &...
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Field redefinitions in the Higgs mechanism
Consider the Higg's mechanism for a simple $U(1)$ theory. Leaving aside the lagrangian which consists of a kinetic term for the gauge field, a covariant derivative term and the potential term for the ...
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Why is isospin utilized in determining the branching fraction of $K_1(1270)\to K\pi\pi$ final states?
The branching fraction of $\mathcal{B}_{K_1 \rightarrow K^{+} \pi^{+}\pi^{-}}$ is determined by $$\mathcal{B}_{K_1 \rightarrow K^{+} \pi^{+}\pi^{-}}=\frac{1}{3} \times \mathcal{B}_{K_1 \rightarrow K \...
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Contribution of dark matter to running of physical constants
I read that "essentially everything in the Standard Model impacts the running of every physical constant in the Standard Model. So, if there is even a single particle missing from the Standard ...
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