Quarks Definition and 258 Threads

  1. ChrisVer

    What is the Contribution of Heavy Quarks to Proton Structure?

    I am looking at the structure of protons, and in my script, when they define the Parton Distribution Functions of all parton species they say that the integral over PDFs of all parton species yields a total momentum fraction of: \sum_i \int_{0}^{1} f_{i}(x) x dx =1 where i denots the...
  2. A

    What Are Quarks? Existence & Properties

    well, what are they? do they exist?
  3. Einj

    What is the Number of Quarks Operator in Quantum Field Theory?

    Hi everyone. In QFT one usually defines the "number of valence quarks" of a certain particle via the operator: $$ \hat N_{val}=\sum_f |\hat Q_f|,$$ where: $$ \hat Q_f=\int d^3x \bar \psi_f\gamma_0\psi_f.$$ According to this definition I expected, for example, for the J/\psi to have...
  4. H

    Quark Stability: Light vs Heavy - Why Study?

    I'm a new comer to study the hadron physics.Why light quarks are more stable than heavy quarks and which one is easy to study? why? Thank you
  5. J

    How position of quarks decide the type of elementey particles ?

    I red the book halliday resnick I come to know protons and other such elementry particles are composed of further subparticles called quarks also that these quarks decide rather its proton or antiproton as if the arrangement of quarks are like 2up quarks up and 1down quark down then...
  6. H

    Relation between momentum and mass of quarks

    We say on-shell and off-shell mass of quarks. 1) What is the difference on-shell and off-shell mass of quarks. 2) At lab. center of mass frame for lepton particles p2= -m2. Can we apply this equation for quarks. Thank you!
  7. X

    Quarks and Strong Attraction Calculation

    Since Colour Force is Strong Interaction, is there a equation to calculate Strong Interaction or express it mathematically? The closest I came to is the Coupling Constant but it doesn't provide a equation for Colour Force. I was also looking at the Gluon Field Strength Tensor, is this related...
  8. H

    Can the separation of quarks create new baryon matter?

    I read recently, that by separating two quarks, once a high enough energy has been introduced, new quark pairs will form. This sounds to me like a meson, being turned into two mesons. I don't know how clear I am on this, but I was wondering... Is the same true for Baryons. If we magically...
  9. H

    Calculating the Theoretical Mass of Quarks and Hadrons: Is it Possible?

    Hi people, I've read some articles about the calculation of mass spectrum. But I'm not clear with this concept. Can we calculate theoretically the mass of quarks. If yes, how? because we never see an isolate quark. Off curse experimentally we can. And my second question is about the mass of...
  10. Z

    Isolating Quarks - Understanding the Logic

    Ok so I want to preface my question with the fact that I'm not trying to present a crackpot theory, I obviously have a flaw in my logic I just need a little correcting. So I was reading about gluons and read that they had to have a mass to allow the strong force to have a limiting range. So...
  11. F

    Electromagnetism - interaction between the electron and the quarks

    electromagnetism -- interaction between the electron and the quarks Which theory explains the electromagnetic interaction between the electron and the quarks within a hydrogen atom ? Is it QED or should I look at Standard Model ?
  12. P

    How Did Quarks Occur in the Early Universe?

    How were quarks occurred ? (in the early universe) Thanks
  13. alemsalem

    Can black holes have net color charge? can a BHs help separate quarks?

    similar to the rough picture of how BHs radiate if I put a proton next to a BH can one of the quarks be absorbed into the BH and the other two escape? I don't really understand confinement very well but does the confinement picture change next to BH horizon?
  14. N

    Reconciling quarks and the uncertainty principle

    As a result of some precise experimental data, we now know that the mass of the quark is not naively 1/3 the mass of the proton. The most recent estimates for the mass of the quark is: Masses of the current quarks: = 2 - 8 MeV/c2 = 1.0 - 1.6 GeV/c2 = 168 - 192 GeV/c2...
  15. J

    How can we be certain that particles such as quarks and leptons are in

    Centuries ago, Greek philosophers (such as Democritus) postulated that atoms were the fundamental building blocks of matter. Then, in the 1900s Rutherford along with others discovered that atoms consisted of electrons surrounding a nucleus made up of protons and neutrons. With the technological...
  16. P

    What happens to the gluon linking Quarks at time of formation of quark

    what happens to the gluon linking Quarks at time of formation of quark star? whether the quark star consists of only quarks or quark gluon plasma?
  17. T

    What is the diference between right handed neutrinos And quarks?

    In the traditional Standard Model, Why right handed quarks can have mass And there can't be any right handed neutrino? Wikipedia says that it damages renormalizability, but why does that not happen with the corresponding quarks? In other words, why did you invent the see saw mechanism for...
  18. L

    Why quarks' wave functions are eigenstates of I and Iz

    This might sound like a totally dumb question but anyway: QCD lagrangian in the limit of mu=md has flavor SU(2) symmetry with respect these two quarks. And we say that these quarks' wave functions are eigenstates of I and Iz. The question is why? Thanks.
  19. G

    How Do Quark Spin States Influence Particle Symmetry and Identification?

    If two quarks are in a S=1 state, are they in either ##|\uparrow \uparrow \rangle ## or ## |\downarrow \downarrow \rangle ## ?
  20. F

    Calculating the Potential Energy of Quarks in the Quark Model of the Neutron

    Quark Model of the Neutron According to the quark model of fundamental particles, neutrons-the neutral particles in an atom's nucleus-are composed of three quarks. Two of these quarks are "down" quarks, each with a charge of ; the third quark is an "up" quark, with a charge of . This gives the...
  21. G

    Gravity affects quarks at the Planck length and Planck energy

    This comes form the wiki article on quarks: Does that mean that when two Quarks come as close to each other as the Planck distance 10-33m then gravity must be taken account if one is to understand their movement? I know vaguely that the Planck energy is the point at which a black hole...
  22. W

    Compositeness of quarks and leptons

    Is the discovery of Higgs boson contradict the Compositeness model and the preon existence ?!
  23. N

    How can we measure the mass of quarks?

    I have not yet studied experimental physics!But I would like to know how can we measure the mass of quark,because we can not to have separate quark for color confinement.In quarkonium,by resonance we know the excited state of quarkonium,but how can we know which state they lie(e.g 2^{3}S).
  24. arivero

    Mass of the proton with massless quarks?

    A usual lore from chiral perturbation theory is that the mass of the pion is proportional to the sum of the up and down masses, and then it is going to be zero when such masses are zero. Now, for the proton, I notice the following remark from Chris Quigg Why is it different of the pion?
  25. Spinnor

    Feynman diagrams from Quarks and Leptons Halzen and Martin?

    Feynman diagrams from "Quarks and Leptons" Halzen and Martin? The following scan is from Quarks and Leptons: An Introductory Course in Modern Particle Physics, Francis Halzen (Author), Alan D. Martin (Author), page 9. Can I take anything from the topological difference between figure (b) and...
  26. nukeman

    Simple physics questions about Atoms and Quarks - Thanks

    Hey guys, Do the quarks determine the element? If I have a atom that has let's say 5 neutrons and 5 protons, and then all of a sudden one of the quarks changes from a down quark to a up quark, this will then change the ratio/amount of protons and neutrons thus changing the element? What...
  27. I

    Do all quarks get annihilated?

    Im aware of quark antiquark annihilation in a proton and have heard one opinon but want another. Do all the quarks get annihilated and just the number remain 3 remain constant in the proton or are the 2 up and 1 down quark the specific quarks that exist in the middle of the storm and they never...
  28. E

    Pauli exclusion principle and fermions, bosons and quarks

    Homework Statement Which of these particles don't follow Pauli exclusion principle and thus have a symmetric wave function? a) Bosons b) Fermions c) Quarks d) All particles follow Pauli exclusion principle Homework Equations None. The Attempt at a Solution I think that...
  29. H

    Xi decay quarks conserved but flavour not conserved

    Hi I have been looking into particle physics and i came across this question but i can not find the answer, the quetsion is as follows: the xi particle decays into the following \Xi -> \wedge + \Pi^{-} dds -> sud + \overline{u}d the quark numbers are conserved but the...
  30. K

    Quark Confinement and the discovery of quarks

    Okay, so I've just begun to have a grasp on the concepts of quantum chromodynamics. And what amazes me is that quarks never actually exist on their own as a single particle because of the strong interaction between them. I've read that when you try to pull apart a pair of quarks that is bonded...
  31. M

    Need Help Deciding: From xrays to quarks or the unconscious quantum

    Need Help Deciding: "From xrays to quarks" or "the unconscious quantum" so I never would have expected myself to wind up here for most of my existence, but I recently had an epiphany on my life. I held out for awhile to see if it was just a fad my brain had gone into, but i become more and more...
  32. Z

    Single quarks vs the top quark

    You often see written that quarks cannot exist by themselves and only exist in mesons (2-quark combos) or baryons (3-quark combos). Yet you also see the top quark referred to as existing by itself. Which is right?
  33. G

    How does a gluon hold quarks together

    Here is a quote from Susskind's the Cosmic Landscape: I'm having a very difficult time wrapping my head around this. I'm pessimistic that it can be explained how gluon's hold quarks together because in order to explain x you need to break x down into parts and as of yet we do not know of...
  34. R

    Standard Model Particles: 6 Quarks & 5 Bosons

    Can someone give me the names of all the particles that the standard model refers too remember the first 18... 6 quarks (up- down,top-botoom,nice-paradox) x 3 colors = 18 and i also remeber the mpozons (photon,gluion,higgs,w and z ) :confused: thank you ____________________ antonis...
  35. Feeble Wonk

    How Does Fractional Charge in Quarks Relate to Electroweak Symmetry Breaking?

    Please help me understand. It seems to me that the fractional charge of a quark suggests that this is actually the smallest (most fundamental) unit of charge, and that an electron has a combined unit charge.
  36. O

    Down quarks force vs ten tonnes truck force

    I have calculated that the strong repulsive force between two down quarks is 25.3N. A book that I am reading said that the force of attraction between two quarks is 'equivalent to the weight of a ten tonne truck’, whose force is equals to 98000N. How can I compare the values of these two forces...
  37. 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?
  38. P

    Do Third Generation Quarks Decay at Slower Rates?

    I know that things moving closer to the speed of light will decay at slower rates, but does this include the decay of third generation quarks into second and then first generation quarks? If a third generation quark is created and in an area of the universe where things are moving extremely...
  39. L

    Are Quarks Composed of Strings or Photons?

    The question is in the title: What are quarks made of? Strings? Thanks.
  40. 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...
  41. K

    How did scientists prove that quarks exist?

    I heard that it had something to do with acceleration in a huge accelerator in fermi-lab but where they can collide going at speeds close to the speed of light , but how does this collision help. Or is this not the way they used?
  42. A

    Do they know how many types of quarks exist?

    Do physicists know exactly how many types of quarks exist? does this allow them to predict some particles should exist like Higgs Boson?
  43. R

    Quarks can form mini blackholes

    this passage is from Paul Davies' the Last Three Minutes: I have a very difficult time believing and understanding this. Why would two quarks being in close proximity create a black hole? A nucleus is only 3 orders of magnitude larger than a quark which i like mount everest compared to a...
  44. Y

    Do quarks temporarily lose mass when giving off gravitons?

    Imagine a quark, which has x mass. The quark gives off a graviton, which has y energy. My question is, before the graviton "snaps" back, would the quark lose mass equivalent to y energy? That is, xnew = xold - y Where xold is the mass of the quark, xnew is the mass of the quark after...
  45. A

    Quarks Explained - Types and Brief Explanation

    i have heard that there are different types of quarks. what are they? and i would be thankfull for a brief explanation.
  46. W

    Understanding Quarks, Anti-Quarks, and Gluons: A Confused WilliamJ's Inquiry

    I have been learning some stuff off of youtube, but I did not get a full enough understanding of how quarks have colors, and anti-quarks have anti-colors and how the gluons have to be colors and anti-colors and how it all works. Some of it doesn't make any sense. The first question is about a...
  47. S

    Classifying Quarks: Understanding Mesons, Baryons, and Quark Families

    when want to illustrate messon and bayyons , we put u,d,s together; but when talk about family we put u,d together and c,s together. why? I am really confused!
  48. Y

    Flipping Down Quarks to Up Quarks: Exploring the Possibilities

    Is it possible to flip flop a down quark to an up quark? I saw another thread on here but it didn't really provide a good answer that I was looking for. Thank you.
  49. T

    Are quarks as sub-atomic as it gets? necessarily?

    is there anything that says there can't be anything smaller than a quark? Can a quark be divided into sub-quark particles...in theory
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