Questions tagged [baryons]
Baryons are hadrons (particles composed of quarks) with an odd number, at least 3, of valence quarks. The term is also often used in astrophysics, e.g. "baryonic matter", with a much looser definition understood to mean any matter composed mostly of baryons, but which may also include leptons and other particles, often in opposition to "dark matter".
31 questions with no upvoted or accepted answers
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Chiral WZW term for Hadron Supersymmetry?
Remarkably, an approximate supersymmetry not in the color- but in the flavor-sector is experimentally observed: hadron supersymmetry, relating mesons (the bosons) to baryons (the fermions).
The most ...
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Final-state baryons in $p \bar p$ collisions in Pythia
I'm trying to simulate inclusive $\chi_c$ production in $p \bar p$ collisions at very low energies (~ 5.5 GeV) using Pythia8 event generator. Leaving aside problems bounded with applicability of ...
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Number of baryons in the Skyrme model
In QCD, the Eightfold Way organizes the number of baryons with respect to their flavor and color quantum numbers: for three light $(u,d,s)$ quark constituents, a spin-(1/2) baryon octet and a spin-(3/...
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Why is there not enough CP violation to account for baryogenesis in the SM?
One of Sakharov conditions states that both C and CP symmetries must be violated by a theory which includes any baryogenesis mechanism. The Standard Model happens to be such a theory, and happens to ...
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’t Hooft anomaly matching and massless baryons
In Lectures on Gauge Theory by David Tong there is statement (section 5.6.3 The Vafa-Witten-Weingarten Theorems), that:
To invoke the full power of ’t Hooft anomaly matching, we needed to assume that ...
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Spin of skyrmion
Baryons can be considered as solitions in Skyrme model(See also this post.):
Such Lagrangian haven't any information about number of colors. Bosonic or fermionic nature of baryons depends on number ...
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Why are spin 1/2 baryons less massive/energetic than spin 3/2 ones?
I am just wondering why the lower spin state multiplets for both baryons (when looking at $L=0$ and considering only the u d and s quarks) are lower in energy i.e. the 1/2+ multiplet is lower than the ...
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Which force is responsible for $\Sigma$(1385) decay?
I was looking at the excited state of the $\Sigma^+$, the $\Sigma^{*+}(1385)$, on Wikipedia. I was wondering which forces are responsible for its two most dominant decays
$$ \Sigma^{*+}(1385) \to \...
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Could exotic baryons be stable inside exotic stars?
Neutrons are stable inside a neutron star because beta decay doesn't release enough energy to send the proton and electron up to the Fermi energy. Could this principle apply to baryons that have charm,...
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Is there an experimental technique for specifically producing Delta minus baryons and clearly detecting the products of their decay?
Formerly I thought that Delta minus baryon was discovered in cosmic rays. However I was mistaken. Wikipedia says that Delta states were "established experimentally at the University of Chicago ...
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Understanding Baryonic Acoustic Oscillations
I was reading the book of Barbara Ryden "Introduction to cosmology":
In the chapter number 9, in the page 203. She says:
"The photons, electrons, and protons together make a single ...
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Relativistic mass of components gives system rest mass?
To put it briefly, in the classic thought experiment of a massless box with mirrored insides containing photons, does the relativistic mass of the photons imbue the box with rest mass?
I take it that'...
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About the asymmetry of baryons
I don't understand why CP violation is insufficient to explain the observed baryon asymmetry?
And how do you solve it using the lepton sector?
Key Words:
CKM - Cabibbo-Kobayashi-Maskawa Matrix: in ...
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Why do we have only 4 SU(2) total spin and isospin 3/2 baryons?
In the context of SU(2), we find that for a quark triplet $qqq$ there are 4 wavefunctions of total Isospin $3/2$, ranging for $I_3$ going from $-3/2$ to $3/2$. Furthermore, these wavefunctions are ...
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How do trace element abundances show that dark matter exists in both baryonic and non - baryonic forms?
I can't seem to find an answer to this question anywhere, any help would be greatly appreciated.
Thanks in advance.
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Baryon effective Lagrangian
I'm trying to understand how to construct effective lagrangians for the hadrons. I understand the procedure for the mesons but I get stuck on baryons. In particular I don't understand how the baryons ...
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What does it mean, during the Grand Unified Epoch, that matter fluctuated between lepton and baryon states?
My understanding of leptons and baryons is that leptons are an elementary particle, while baryons are a composite particle. Can someone explain to me what particles fluctuating between lepton and ...
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Which hadrons were present after the phase transition from the post-Big Bang QGP?
This question relates to the "hadron epoch" (after the initial quark-gluon plasma, but before the end of baryogenesis).
My understanding is that the phase transition that ends the quark-...
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Octet and decuplet baryon wavefunction
I read the octet and decuplet baryons symmetric and anti-symmetric wavefunction from 'Riazzudin and Fiazzudin's book. But I am little confused about the wavefunction of neutral sigma and Lambda baryon....
user368315
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Spinor index contractions for baryons
For an $SU(N)$ QCD with $N_f$ flavours one writes baryons as
\begin{equation}
B^{{a_1}…a_{{N}_f}}=\epsilon^{i_1…i_N}\psi_{i_1}^{a_1}… \psi_{i_N}^{a_{Ν_f}}
\end{equation}
by contracting the colour ...
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Higgs decay into baryon-antibaryon pair
I have an exercise for "Introduction to high energy physics" and I'm baffled. The exercise states:
Problem: Higgs particle of mass 125.7 GeV decays in an exclusive channel of baryon-...
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Why is the density of atoms in space so much higher than the baryon density from BBN and CMB?
If you ask the question: "how many atoms per cubic meter in space", you can get a consensus of around $5$ atoms per cubic cm or about $5\times 10^6\space \text{atoms}\space m^{-3}$. If we ...
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What is the (model independent) density of baryons in the Universe?
I know that Planck has measured the baryon density, $\Omega_B$, as a fraction of the critical density, $\rho_{CRIT}$. Is there a measurement of baryon density that's independent of the critical mass ...
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How are the middle two baryons in the baryon octet obtained?
I understand that it has to be a combination of $u$, $d$ and $s$ such that it is antisymmetric in two indices, but how is this specific combination obtained?
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Expanding isospin symmetry to $SU(3)$ flavor symmetry for Baryon octet diagram
Let's consider about the Baryon octet diagram. We can identify the isospin $I_3$ symmetry by noticing the mirror symmetry with respect to the $I_3$, i.e. x-axis. However, how can we expand this into $...
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Quark Model Families
I cannot understand what we mean when we say that we organise baryons and mesons in families. In other words, i have seen that a lot of books mention the baryon J=1/2 family. What do we mean by that? ...
user243882
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Quark Model Family
I have studied the baryon J=1/2 family.i did the $(Y,I_3) $ diagram and started from the highest weight $(\frac{1} {2} ,\frac{\sqrt{3} }{2}) $ which is the proton and used the operators $I_{+-} \ \ U_{...
user243882
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What if there was no baryon-antibaryon asymmetry in our universe?
We know that the universe goes through different evolutionary phases: radiation, matter and later dark energy epoch.
What would happen if there was no baryon-antibaryon asymmetry? How would the ...
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B violation and electric charge
Within SM you can prove that despite we have baryon number conservation respect to Noether theorem, at quantum level baryon (and lepton) number is violated as
$$
\Delta B = 3·\Delta n_{CS}, \quad n_{...
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What are the known ways to model baryons in string theory?
As I understand, string theory models baryons by including a so called "baryon vertex".
Is this right?
It seems that baryon vertex's are usually D/M branes. Is that always the case?
user164839
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Can indistinguishable particle wavefunctions be written as a product of total observable eigenstates?
Consider the wavefunction of say two electrons in an external potential, associated with two possible states $\phi_a$ and $\phi_b$. Furthermore, each electron can have two spin states $\chi_1$ and $\...
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