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".
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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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Mass of mesons and baryons
In my introduction to nucleons and particles (basic) course, we were given the following formula to compute the mass of mesons and baryons :
\begin{eqnarray}
M(\text{meson}) & = & m_1 + m_2 ...
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Basic question on spin wavefunction
In my textbook, I am told that the $\Delta$ is a spin-3/2 particle made up of three spin-1/2 quarks. For a state with definite spin $m=-1/2$, I'm given that the spin wavefunction $$\dfrac{1}{\sqrt{3}}(...
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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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Space and spin symmetry in light baryons
In Particle Physics by Martin and Shaw in Ch.6 they show how the baryon supermultiplets are built from the assumption that the space and spin wave functions are symmetrical, so eg. $uud$ has spins up,...
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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 heavy bosons are unstable?
I'm working with dark matter and in the some of concepts is that shall exist WIMPs (weakly interacting massive particles) in which are made by baryons... However, we know that this cannot satisfy the ...
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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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Why is the proton the only stable hadron?
The title pretty much explains the question, but I've always thought that it'd be a neutron because of its 0 charge.
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Identifying the flavour singlet baryon
I would like to ask how to identify the lowest lying flavour-singlet baryon in the data on known states of particles. So far I managed to derive the following constraints:
Its quark content must be $...
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Can an anti-hydrogen atom decay into a hydrogen atom?
I was thinking about Baryon asymmetry just to mess around with ideas and thought about this. Could it be that all the anti-matter decayed into matter?
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Difference between particle and state
I have recently started studying particle physics, and I was surprised by the description of hadrons. At first I was told that the $\Delta^0$ baryon was composed by one up and two down quarks, and ...
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If Baryons are subject to the strong nuclear force, how are they involved in Beta decay?
The question is really in the title with this one, I just need a little bit of clarity, consider beta-minus decay, which is an interaction governed by the weak nuclear force, $$n\to p^+ +e^- +\bar v_e$...
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Density of baryons
I wanted to recalculate the number of atoms in the universe according to What paper can I cite for the estimated number of atoms in the observable universe to be lower than $10^{82}$? .
But in the ...
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Why does the $\Lambda^0$ exist?
In looking at the particle charts I see 3 Sigma baryons with very similar masses and other similar properties, which makes sense since they all have one strange quark plus two others from the (up,down)...
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Why do we antisymmetrize the baryon's wavefunction but not the meson's?
A many-body wavefunction of identical fermions must be antisymmetrized because of fermionic statistics. We don’t antisymmetrize the meson wavefunction because it contains a quark and an antiquark, and ...
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How could we determine the color of a black hole's hair?
It was once thought that black holes were characterized by their mass, charge, and angular momentum. This was known as the no-hair conjecture. More recent work on black hole physics (see here) ...
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$SU(3)_F$ flavour symmetry and $SU(2)$ isospin symmetry
There is an approximate $SU(3)_F$ flavour symmetry that exists at the quark level between $u$, $d$ and $s$ quarks. But we often talk about an approximate isospin $SU(2)$ between up and down quark only?...
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Which came first: leptons or baryons?
If you had a big collection of neutrons, they could decay into protons, electrons, and neutrinos through beta decay since protons are the only stable baryons. After a while, you should get hydrogen ...
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What is the ratio of gluons to baryons?
Gluons bond quarks into baryons (i.e., protons and neutrons). For example, two up quarks and one down quark form a proton while one up quark and two down quarks form a neutron. Is there one gluon per ...
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How to Derive Baryon Octet Matrix?
In every textbook on particle physics that I've read, I encounter the following matrix when reading about matrix of wave functions for the baryon octet:
$$\left[\begin{array}{ccc} \frac{\Sigma^0}{\...
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Confusion in proton decay
I read that a proton cannot decay because it is the least massive baryon. However, in positron emission, the proton converts to a neutron a releases a positron. Is that considered a proton decay?
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Is the neutron its own antiparticle? [duplicate]
I have seen multiple claims that the neutron is its own antiparticle. However surely the antiparticle of the neutron would have a baryon number of -1 because it would consist of three antiquarks, each ...
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$\Omega^0_c \to \Sigma^+ K^-K^- \pi^+$ Feynman diagram
How can I work out the Feynman diagram for the decay process, $\Omega^0_c \to \Sigma^+ K^-K^- \pi^+$?
user147457
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$\Sigma^{+}$ baryon decay- why no decays to neutron and electron-neutrino pair?
I am working on a homework problem involving a decay of the form
$\Sigma^+\rightarrow n+e^++\nu_e$,
with the goal of providing justification for why this decay is not experimentally observed. To ...
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How can we explain that $\Sigma \pm$ have different masses whereas K$\pm$ have the same mass?
I guess it is because of the forces between the quarks inside them but I am not quite sure how to explain it.
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Is it true that neutrinos are billions of times more than all baryonic matter and electrons?
Here, it mentions that the total number of electrons in the observable universe is around 10^80, while this states that the total number of baryons are again, ...
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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 topological excitations of the pion field carry a baryon number?
I have heard (numerous times) that topologically nontrivial pion field configurations carry baryon number. It's clear the the field configurations can carry a topological quantum number (the winding ...
Buzz♦
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Could matter and antimatter have drifted away early after Big Bang?
Early after Big Bang, could small parts of matter and antimatter have drifted away in opposite directions and thus still be able to maintain anti/matter balance, but keep local isolated pockets that ...
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Sigma+ quark structure
Does sigma+ have 2 quark structures, if so are they uus and (anti)d (anti)d (anti)s ? Both these structures are the same charge (+) so I guess it would make sense however I can't find much about it ...
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Why is the calculated Power Spectrum peak at $l=302$ different from the chart peak at $l=220$?
This is a follow-up to a really basic question I had: How is the first acoustic peak calculated in CMB? Plank quotes an angular size of the sound horizon at 0.0104, but that corresponds to an ...
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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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Sigma baryons have strangeness
An exercise I am trying to solve is as follows:
$Σ$ baryons have a charge of either ${-1,0,+1}$. Show that their strangeness is $S=-1$.
I thought one can argue that since they are baryon, they'll be ...
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What's the difference between Quark Colors and Quark Flavours?
Each of the six "flavors" of quarks can have three different "colors". The quark forces are attractive only in "colorless" combinations of three quarks (baryons), quark-antiquark pairs (mesons) and ...
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Baryon / photon ratio
The key parameter which determines the abundances of light elements is the baryon/photon ratio. Is this ratio derived from first principles -if so, how- or, if it results from a small favoritism for ...
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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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Derivation of Gell-Mann Okubo relation for mesons
In SU(3) quark model of hadronic structure one assumes that mass splitings between hadrons is due to difference between masses of $s$ quark and $u,d$. This is modeled by perturbation Hamiltonian $$ \...
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Why is there no baryon isospin singlet with spin 3/2?
All of the baryons in the spin-1/2 octet except the $\Lambda$ isospin singlet have spin-3/2 excited states in the baryon decuplet. What is it that prevents the existence of a $\Lambda^{*}$ baryon with ...
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Is there a reason why every meson and baryon has an integer electric charge? [duplicate]
Is there a reason why every meson and baryon has an integer electric charge?
For example, why is there no meson existing of two up quarks, giving a charge of $\frac43$?
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Can superpositions of baryons with different electric charge and strangeness exist?
I am trying to find out whether the following baryons can exist:
$$ |X\rangle = \frac{|u u u\rangle + |d d d\rangle + |s s s\rangle}{\sqrt{3}} $$
$$ |Y\rangle = \frac{|u u u\rangle + |d d d\rangle - ...
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How can $\Lambda^0$ and $\Sigma^0$ both have $uds$ quark content?
Title says it all: How can $\Lambda^0$ and $\Sigma^0$ both have $uds$ quark content? Doesn't this make them the same baryon?
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Strange Matter and Stars
I am researching some stuff for a WorldBuilding.SE question, which asks if there is a true scientific method (not necessarily at our current technology level) to create a bomb capable of destroying a ...
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Baryon - Anti Baryon scattering
Is it possible, for a strong interaction of the above described type (baryon - anti baryon), to exist?
$$B + \bar B \to \ldots $$
(Where $B$ is a generic baryon and $\bar B$ the anti-)
Namely like ...
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Baryons annihilation
I was wondering if there is a way of calculate the annihilation cross section for two baryons, say $p\bar p\to\pi\pi$ or $p\bar p\to\gamma\gamma$. The problem here is that we cannot use the usual ...
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Colorless charge in a baryon
In a baryon there are 3 quarks and in a meson there are one quark + one anti-quark.
So color charge is colorless ( a color singlet state ) in a meson.
But how is it colorless in a baryon?
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Why do quarks and antiquarks tend to bond in groups in which the number of quarks minus the number of antiquarks is divisible by 3?
Why do quarks and antiquarks tend to bond in groups with quark number a multiple of 3?
I understand why they might in bond in groups of three to create a net charge of zero (i.e. neutrons), but I don'...
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Can a neutron decay to the gravitons?
Is it possible that a bunch of neutrons totally decay to the graviton? In other words, does the baryon number conserve in the quantum gravity interactions?
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What is the physical meaning of $\alpha$ in this disintegration problem?
I am taking a course where I have to solve the following problem related to the disintegration of a baryon in a proton and a pion $(\Lambda \to p^+ + \pi^-)$:
Assume that a $\Lambda$ particle with ...
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Angular momentum in baryon multiplets
In the Murray Gell-Mann model, particles are brought together as a function of their angular momentum.
The classification diagrams can be seen as irreducible representations of $SU(3)$, following ...
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