What is Baryons: Definition and 42 Discussions

In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified as fermions because they have half-integer spin.
The name "baryon", introduced by Abraham Pais, comes from the Greek word for "heavy" (βαρύς, barýs), because, at the time of their naming, most known elementary particles had lower masses than the baryons. Each baryon has a corresponding antiparticle (antibaryon) where their corresponding antiquarks replace quarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark.
Because they are composed of quarks, baryons participate in the strong interaction, which is mediated by particles known as gluons. The most familiar baryons are protons and neutrons, both of which contain three quarks, and for this reason they are sometimes called triquarks. These particles make up most of the mass of the visible matter in the universe and compose the nucleus of every atom. (Electrons, the other major component of the atom, are members of a different family of particles called leptons; leptons do not interact via the strong force.) Exotic baryons containing five quarks, called pentaquarks, have also been discovered and studied.
A census of the Universe's baryons indicates that 10% of them could be found inside galaxies, 50 to 60% in the circumgalactic medium, and the remaining 30 to 40% could be located in the warm–hot intergalactic medium (WHIM).

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  1. O

    I Question on Baryons and Specific Decays

    1) We know in case of beta decay if there is excess of protons or neutrons in the nucleus beta decay take place. Force involved - weak interaction Reason involved - to stabilize, to obtain proton neuton 1:1 ratio in the nucleus. E. g., Beta minus - Carbon 14 transforms into Nitrogen 14 2) Case...
  2. bbbl67

    I Would higher-mass quarks result in smaller baryons?

    Would baryons not made with standard Up or Down quarks exhibit smaller radii than neutrons and protons? I'm thinking like for example how muons have much smaller orbitals than electrons, on the lepton side of things.
  3. M

    Ray Kurzweil and What elements could exotic baryons create?

    I was reading the Exotic baryons page on Wikipedia and a cited source said that Ray Kurzweil, renowned Futurist said that at the end of the 21st century, we could use femtotechnology to create new chemical elements from exotic baryons that could create a new periodic table of elements. Here is...
  4. F

    A Exploring the Existence of Baryons with Positive Strangeness

    Hi all, I read on "Intoduction to Elementary Particle Physics" (A. Bettini) that baryons with positive strangeness cannot exist. I don't know what to conclude from this sentence: sigma-baryons have negative strangeness, since there's a sigma as valence quark. But these baryons have, of course...
  5. M

    A New model of high-spin Baryons

    They are described here as (2+1)-dimensional sheets of eta-prime condensate, with the valence quarks on the boundary. One amazing detail is that, because it is a lower-dimensional object, the quarks are anyons! This description is said to apply most immediately to single-flavor baryons like ∆++...
  6. wolram

    B Does dark matter interact with Baryons?

    This paper says they do. but I have been lead to believe that DM only interacts with gravity https://arxiv.org/abs/1811.08843 What is the standard view?
  7. H

    I Can Atoms & Baryons Exist Inside a Black Hole?

    In the way I naively imagine a black hole's interior there are event horizons all the way down, and any material object of whatever size will straddle many event horizons. So, with both atoms and baryons, there cannot be any interaction between their components. Consequently, at the moment of...
  8. C

    Can charged baryons flow induce magnetic field?

    We all think that electric current is the electrons flow without mass transfer in conductor, i.e. charged lepton flow. But charged baryons flow can also deemed as "electric" current, e.g. ionic current. My question is that charged baryons flow can induce magnetic field? Same amperes, then same B...
  9. M

    A Attractive strong force, isospin and hypercharges

    In the electromagnetic interaction, opposite electric charges q attract each other. In the strong nuclear force, the proton p(uud) is attracted to p(uud) and the neutron n(udd), and n(udd) is attracted to p(uud) and n(udd). Both neutrons and protons have a hypercharge Y=+1, and 3rd...
  10. S

    I Which baryons can annihilate?

    Different baryons routinely annihilate. Like antineutron and proton. Wikipedia article on annihilation acknowledges this. But at https://en.wikipedia.org/wiki/Annihilation#Proton-antiproton_annihilation near end of first section, I find statement: The most common (lowest energy and longest...
  11. Eric Putney

    I Can a (uuu) baryon exist? If so, why wouldn't protons decay

    Is this some sort of issue with color or another quantity that needs to be conserved?
  12. Xico Sim

    I Mesons and baryons written in terms of quarks

    Hello, guys. I have not understood what it means when one writes ##\pi^+=u\bar{d}##, for example. I though it simply meant that the ##\pi^+## meson was composed of one up-quark and one anti-down-quark. However, that doesn't explain what writing ##\pi^0=\frac{1}{\sqrt{2}}(d\bar{d}-u\bar{u})##...
  13. S

    How can non-baryonic matter be obtained through electromagnetic manipulation?

    Greetings. Professionally, I'm more inclined to the study of man's past than to his physical world - however, as history includes all that was (and, depending on whom you ask, all that will be), I find myself a poor son of Athena; rich in wisdom past, but light in knowledge present. My current...
  14. Andrea M.

    Calculate Baryons Annihilation Cross Sections

    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 chiral theory because the energy transfer is of the same order of the cutoff ##\Lambda\sim 1...
  15. wolram

    MOND and the missing baryons problem

    http://arxiv.org/pdf/1508.04001v2.pdf Although i am not a proponent of MOND this paper gives an alternative to the missing baryons problem The colliding ‘Bullet Cluster’ is often adduced as strong evidence for DM, with the understood – 3 – implication that it is evidence for the...
  16. M

    Cosmic Invent. HW: Determine Densities & Measurements

    Homework Statement One of our homework problems asks us to state the density of Baryons, Cold Dark Matter, Radiation, Dark Energy, and the total density of the universe in terms of the critical density today. It also states to give the density of each quantity in dimensionless Omega units (the...
  17. J

    Octets for Baryons: What is the Other Octet?

    Hi, I am just learning some materials and struggling to find what the other octet is. I know the following: 3 \otimes 3 \otimes 3 = 10 \oplus 8 \oplus 8 \oplus 1 Now I understand the 10 and one of the 8's. But I am a little unsure of what the other octet and singlet is in terms of quarks...
  18. Superposed_Cat

    Difference between delta baryons and nucleons

    Hello, I have had this question for awhile now. What is the difference a delta baryon and a nucleon? they seem to have the same quark composition? Thanks in advance.
  19. W

    Ripping apart baryons at the end of the universe creating new particles?

    The post might be in the wrong forum, and it's likely that a similar question has been asked earlier, but I couldn't find it with my feeble attempts at searching.It's apparently well known that you can't rip quarks away from each other and get singular quarks. The gluon bond gets stronger with...
  20. S

    Do baryons only decay via the weak force?

    Provided they aren't in an excited state (which would allow a decay via EM or strong). I had a question asking why the neutral lambda particle, consisting of uds quarks, has a lifetime characteristic of the weak. The answer being that it must decay via the weak to change the s-quark flavour into...
  21. Q

    All baryons eventually decay into protons, is this the same with anti-bayrons?

    (high school level physics btw) apparently all baryons eventually decay into protons, so I was just curious to know if this was also true of anti-baryons?
  22. B

    Six Baryons that contain a Charm Quark?

    Homework Statement Basically I've been asked to draw a isospin vs. charge diagram - not a problem. But the question states that this is a sextet, but when I look at the combinations/look up baryons with charm quarks - there are many more than six! Am I missing some quark combination rules for...
  23. B

    Half-spin baryons with identicle quarks?

    Do any 1/2 spin baryons exist that are made of three identical (flavored) quarks? I know the Δ-, Δ++ and Ω- have 3/2 spin. If the 1/2 spin versions of these particles can't exist, then why not?
  24. W

    The particle/antiparticle pairs in mesons as well as three quarks in baryons?

    Hi, Does anyone out there know the rules for mesons when it comes to the particle/antiparticle combinations? Is it simply like an up and anti-up quark that makes up a meson or is it like up and anti-down or down and anti-up? Or can it even be other combinations of the six quarks? Also I have...
  25. E

    Nuclear Physics: charmed baryons

    Hi, So I have this problem about baryons: The lightest charmed baryons have quark compositions cab with zero angular momentum (L_12 = L_3 = 0) where c is the charmed quark and a & b can be any of the light quarks (u, d, s). Show that the resulting states can be classified into 3 families...
  26. D

    Stability in the family of baryons

    Of all the baryons, why are protons the only known stable combination of quarks? Why are neutrons more stable by more than billions of times longer than the rest of the unstable baryons? If it is just their combination of quantum numbers, then, why do those combinations work out to being stable?
  27. B

    Difference Between Sigma & Lambda Baryons

    While doing my homework for physics, we are doing what quarks make up different baryons and such and I can across something I don't understand, what is the difference between a neutral sigma baryon and a neutral lambda baryon? They both have an up down and strange quark combination and the...
  28. I

    Ratio of number density of photons to baryons

    Homework Statement photon/baryon ratio = Np/Nb Np, is the number density of the CMB photons Nb, is the number density of baryons Evaluate this ratio at the redshifts z=0 and z=100. From my understanding, if interactions are negligable, particles cannot simply disappear. Therefore...
  29. B

    Explore the World of Baryons: Links to Learn More

    I quoted this from Hyper Physics, and I want to learn more about this, where can I? I am asking for links to places where I can learn about this ( I already know about Protons, Neutrons, Electrons and all the basic ones but now I want to get more in depth): Baryons are massive particles...
  30. J

    Quark Structure of Baryons: Sigma & Lambda

    Hi this isn't actually a homework question more my own curiosity/confusion. They have the same quark constituents and http://en.wikipedia.org/wiki/File:Baryon_octet.png" for both but mass and decay rate are different, please explain. (if the lambda is an excited state of the sigma why isn't it...
  31. F

    How many baryons are there in the universe?

    Many articles and papers say that 4% of all energy in the universe is baryonic. How many baryons does that make? I do not seem to find any wikipedia article or paper that gives an absolute number. Can anybody help? Thank you! François
  32. D

    Different Gravities for Leptons and Baryons

    There was something in last week's NewScientist about the possibility that there are two gravitational forces, one for leptons and one for baryons. Are physicists giving this serious thought?
  33. CarlB

    How many mesons and baryons are there?

    That is, how many different states are there assuming you distinguish two particles as different if they have different quantum numbers or different masses. For example, the \Delta^-(1232),\Delta^0(1232),\Delta^+(1232),\Delta^{++}(1232) are four different states. And these are all different...
  34. K

    Would baryons and their antiparticles interact via the strong interaction?

    And would the potential be equal in magnitude yet opposite in sign? If you were to approximate a yukawa potential for some baryon and had it "near" its antiparticle, what would the potential look like. The same for a baryon and another baryon but opposite? This would just be like a...
  35. J

    Beta Decay, how can baryons produce Leptons ?

    Hey I know : n = p+ + e- + (Ve) meaning that : p+ = n - e- - (Ve) = n + e+ + Ve ?? But, how does a Baryon like a proton or a neutron produce leptons ? and how this change can occur : n = p+ + e- + (Ve) u d d = u u d + e- + (Ve) How can a down quark become a Up...
  36. J

    Pions - how they interact with Baryons

    hey, i was told that in a Atom's Nucleus, Nucleons keep changing from Proton state to Neutron state , and vice versa , by the means of Pions exchange. But how does this works I know : p+ : u u d n : u d d Positive pion (that turns neutron into proton ?) : (d) u u d d + (d) u = u u...
  37. A

    Baryons and their quark constituents

    I have been given an assingment where I must show that the properties of the up, down and strange quarks follow from the properties of the baryons. I am just wondering why delta +1 (a baryon) has a spin 3/2 when it is, like a proton, composed of up, up, down. Aren't spins additive? and how do...
  38. B

    Understanding Omega: Baryons, Leptons, Photons and More

    This question concerns Omega(matter+dark+lambda). We take into account protons(baryons), electrons(leptons), neutrinos, pions, etc etc when trying to determine Omega from the CMB. but what about photons? I mean there are A LOT more photons than baryons. All those photons carry energy...
  39. CarlB

    Nucleon and Delta baryons (resonances)

    Okay, I decided to start trying to understand the nulceon and delta resonances. Does anyone have suggestions for a good explanation of how these work? How many resonances are there? How are they distinguished? Etc. Here's the PDG information...
  40. N

    Two new heavy baryons Discovered

  41. Y

    Baryons & addition of angular momentum

    I was wondering if someone could help me explain this problem. In a baryon, two quarks are in l=0 and one quark is in the l=1 state. Quarks are spin-1/2 particles. What values can the total angular momentum take? I know the answer is 1/2, 3/2, and 5/2, but I'm confused about how they...
  42. K

    How Many Mesons, Baryons, and Leptons Exist?

    Does anyone know how many there are, also how many are just thoeretical. We know of the proton, neutron, and election, but do we know that Tau and Muons exist? Also does anyone think we'll keep finding more