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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Probability of production and decay of Higgs boson [closed]
I am trying to solve a particle physics homework problem but I really don't understand it and my lecture's notes aren't helpful.
I don't understand how you would calculate the probability. I know that ...
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Is there any known reason to take a $\pi$-power ansatz for the first PMNS row seriously?
I noticed a compact numerical fit for the first row of the PMNS matrix.
Using experimental magnitudes roughly of the form
$$
(|U_{e1}|, |U_{e2}|, |U_{e3}|) \approx (0.825, 0.546, 0.149),
$$
one can ...
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What was the Quark-Gluon Plasma state in terms of electric charge in an era when electroweak symmetry had not been broken?
I am trying to understand the analogy to present day plasma. I understand the QGP was color charge neutral. But with quarks having electric charge, as described in the era of the present, was their ...
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The prerequisite books of the GUT theory
AI tell me that humans already have a unified theory for electromagnetism, weak force, and strong force. I want to read these theories.
I'm almost done with the first volume of Feynman's Physics ...
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Higgs field theory, does Higgs field give mass or energy? [closed]
Isn't mass is just energy divided by $c$ squared? If we say something has a mass of 10kg, isn't it that it has energy of 9.10^17 joules and we are just divining it by $c^2$? Using this logic, when ...
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Is CP violation related to a breaking of $SU(2)$ symmetry?
I have a basic understanding of gauge theory in that they are a set of operations or local transformations that leave the Lagrangian/Hamiltonian of a system invariant.
I also understand that CP ...
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Does the antimatter Lambda-Beauty baryon decay into fewer or lighter antimatter particles than the regular version does into matter particles?
I am having a little trouble understanding the recent famous 2025 results from LHCb...
They say the antimatter version of the beauty-containing $Λ$ baryon decays along a specific path about 2.45% less ...
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How do we know individual quarks don't carry all three color charges?
AI says color charge is essentially circulated between quarks via gluons mitigating the strong force interaction, and that a quark can only have one color charge at a time.
How do we know this is true,...
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Unstable Leptons: How are their rest masses (energies) calculated?
Six different leptons are known. Of these, two are unstable: the muon and tau lepton.
According to experimentally obtained data, the rest masses (energies) of these elementary particles are equal to ...
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In string theory, what is currently in 2026 the precise roadblock of describing a universe filled with matter and force fields as we know it?
We know that some people think string theory is the only way to describe QM and gravity so it must be right, while others see reasons to think it is wrong, and the question here is not who of them is ...
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Do we know empirically that electrons have no color charge?
Everything has a gravitational field, so everything is gravitationally charged.
Everything has an electromagnetic field (including quarks), so everything is electromagnetically charged.
Only quarks ...
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Why neutrinos do not interact with matter? [closed]
Why do neutrinos not interact if photons do, if both are massless and chargeless?
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What are the conserved quantities belonging to the rotations of the Higgs field?
If I understand it well, if we rotate that $SU(2)$, the result will be exactly the same system.
That means, it should have some conserved quantity belonging to it.
What is it?
It is clearly not the ...
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What is the long-term fate of an isolated rocky object in a heat-death universe?
What is the long-term fate of an isolated rocky object in a heat-death universe? In a universe approaching heat death, how would an isolated macroscopic solid object such as rocks evolve over ...
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What do the Standard-Model fermion fields $l$, $e$, $q$, $u$, $d$ represent?
From what I understand from this answer, there is no clear-cut answer to the question "how many fermion fields are there in the Standard Model?" or similar questions.
For instance, counting ...
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