What is Strong force: Definition and 98 Discussions

In nuclear physics and particle physics, the strong interaction is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and gravitation. At the range of 10−15 m (1 femtometer), the strong force is approximately 137 times as strong as electromagnetism, 106 times as strong as the weak interaction, and 1038 times as strong as gravitation. The strong nuclear force confines quarks into hadron particles such as the proton and neutron. In addition, the strong force binds these neutrons and protons to create atomic nuclei, where it is called the nuclear force. Most of the mass of a common proton or neutron is the result of the strong force field energy; the individual quarks provide only about 1% of the mass of a proton.
The strong interaction is observable at two ranges and mediated by two force carriers. On a larger scale (about 1 to 3 fm), it is the force (carried by mesons) that binds protons and neutrons (nucleons) together to form the nucleus of an atom. On the smaller scale (less than about 0.8 fm, the radius of a nucleon), it is the force (carried by gluons) that holds quarks together to form protons, neutrons, and other hadron particles. In the latter context, it is often known as the color force. The strong force inherently has such a high strength that hadrons bound by the strong force can produce new massive particles. Thus, if hadrons are struck by high-energy particles, they give rise to new hadrons instead of emitting freely moving radiation (gluons). This property of the strong force is called color confinement, and it prevents the free "emission" of the strong force: instead, in practice, jets of massive particles are produced.
In the context of atomic nuclei, the same strong interaction force (that binds quarks within a nucleon) also binds protons and neutrons together to form a nucleus. In this capacity it is called the nuclear force (or residual strong force). So the residuum from the strong interaction within protons and neutrons also binds nuclei together. As such, the residual strong interaction obeys a distance-dependent behavior between nucleons that is quite different from that when it is acting to bind quarks within nucleons. Additionally, distinctions exist in the binding energies of the nuclear force of nuclear fusion vs nuclear fission. Nuclear fusion accounts for most energy production in the Sun and other stars. Nuclear fission allows for decay of radioactive elements and isotopes, although it is often mediated by the weak interaction. Artificially, the energy associated with the nuclear force is partially released in nuclear power and nuclear weapons, both in uranium or plutonium-based fission weapons and in fusion weapons like the hydrogen bomb.The strong interaction is mediated by the exchange of massless particles called gluons that act between quarks, antiquarks, and other gluons. Gluons are thought to interact with quarks and other gluons by way of a type of charge called color charge. Color charge is analogous to electromagnetic charge, but it comes in three types (±red, ±green, ±blue) rather than one, which results in a different type of force, with different rules of behavior. These rules are detailed in the theory of quantum chromodynamics (QCD), which is the theory of quark–gluon interactions.

View More On Wikipedia.org
  1. hongseok

    I Why the binding energy per nucleon has specific pattern?

    The binding energy per nucleon for each element has a specific pattern. It increases from hydrogen to iron and then decreases again. What is the fundamental reason why the binding energy per nucleon has this pattern? According to my investigation, the range of action of the strong force is...
  2. ValeForce46

    I Separation energy of nucleons and Coulomb barrier

    My professor and the book I'm reading (Particles and Nuclei: An Introduction to the Physical Concepts by Povh et al.) says that "The emitted nucleons are primarily neutrons since they are not hindered by the Coulomb threshold" which means that a neutron has a separation energy lower than a...
  3. Th3

    B What’s the necessity of the strong force?

    To put it simply: Why do we have the strong force? If the goal of the fundamental forces (in a heavily generalized sense) is to bring particles to a lower state of energy, how is the strong force participating to this? Could it be due to atoms being a very stable configuration? If this is the...
  4. Cody Livengood

    B Do Alternative Explanations for Gluons Exist and How Can We Test Them?

    I understand how the existence of quarks is inferred from the three particle-emitting cones or jets and by the quarks’ ability to deflect particles passing through the composite particle, but I don’t see how the existence of gluons is conclusively demonstrated by this rather than just being an...
  5. P

    B Is the Strong Force Really Stronger Than the Electromagnetic Force?

    So I am aware that the strong force is the strongest force with the electromagnetic force being the second strongest force. I am wondering how we go about the process of deciding which force is stronger. I am visualizing a helium nucleus; two protons, two neutrons. The two protons are...
  6. Copernicuson

    I ?Measuring the Strong Force: Strength vs Distance

    Have there been any measurements of the strong force? Also its curve of the strength of the force vs distance
  7. Javier Lopez

    A How Are Coefficients for Nuclear Forces Derived and Validated?

    There are some theories, but I am looking for one that have proven using test data and can be placed in an excel table or a program with coefficients for some common reactions. Do anybody knows a paper with tables or formulas? I found this with a fortran code that is recent...
  8. C

    I Strong force as exchange of mesons, or of quark and antiquark

    The (residual) strong force between nucleons can be desribed as - The exchange of a meson (from a nucleon to the other), as in picture b) - The exchange of a quark and an antiquark: in picture a) one nucleon "gives" a quark and receive an antiquark and it's the opposite for the other I do...
  9. C

    I Does strong force increase or decrease with aligned spins?

    The deuterium exists only with the proton and neutron of aligned spin, which suggests that the residual strong force is greated with aligned spins, i.e. the binding energy is greater if the spins are aligned. On the other hand the mass of ##\Delta^{+}## is greater than the mass of proton ##p##...
  10. C

    I Measuring characteristic time of strong and weak interaction

    Consider a scattering between two particles a and b that produces two particles c and d: d is stable, while c decays in two other different particles e and f. The first interaction is by strong force (time of interaction ##t_1\sim 10^{-23}s##, which is also the time of generation of c and d)...
  11. The Strong Interaction, 1977 - Richard Feynman

    The Strong Interaction, 1977 - Richard Feynman

  12. J

    B Mechanism for Energy Released via the Strong Force in Fusion

    Hi, I was wondering if there is a mechanism to explain how the strong force leads to an energy release when two light nuclei such as hydrogen fuse together. I get that the products of fusion have less mass than the reactants and that this "missing" mass is converted into energy in accordance...
  13. H

    I Is the strong nuclear force stronger than the weak force?

    I've heard that the weak nuclear force is stronger than the electromagnetic force at distances of 10^-18 m. I've also heard that the strong force becomes repulsive at a distance of 0.7 fm. So if two quarks got to a distance of <<10^-18 m which force would win, the strong force or the weak force?
  14. J

    B Question about the Nuclear Strong Force

    Hi, Please could someone explain the differences between the strong interaction (force that hold nucleons together) and the strong force (force that holds quarks together) in terms of the exchange particles. I have been reading several online sources and there seems to be some disagreement...
  15. P

    I Why must the mediator of the strong force be heavy?

    I'm reading Griffith's Introduction to Elementary Particles and it says that when Yukawa proposed his theory of the strong force, it was an indication that the meadiator of that force must be a heavy particle since the force is a short ranged force. Why is that the case? I cannot get the...
  16. 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...
  17. D

    A What is the strength of the strong force in N units

    In addition. 1. what is the presure of this force (alternativly wat is the efferctiv area it is acting on?...nucleai corrss section area?).
  18. Vitani11

    I Why is there no equation for the strong force?

    We can quantify the three other forces but not this one. Why?
  19. Sophrosyne

    I Why are gluons considered to be elementary particles?

    Gluons are often depicted as fundamental particles in the Standard Model. But in looking at their mechanism, it seems they are not really fundamental particles in the sense that they are fundamental, indivisible, building blocks. They are mesons- a composite quark-antiquark pair, where their...
  20. SWFvanRijk

    A Are Mesons in Colour Singlet State?

    I read that hadrons are in colour singlet state and that gluons are not and that the colour singlet gluon is forbidden for the reason of making strong force a long range force otherwise (and that SU(3) has 8 generators and thus 8 gluons) but my question is: are mesons in a colour singlet state...
  21. Bill Myk

    I Strong force and superposition

    I apologize if this question seems like gibberish, Its been annoying me. I tried to ask this once but i didnt ask it properly. If there was a complex structure of sub atomic particles, and each sub atomic particle was in its individual space time vector, or eigenstate, and they where each...
  22. Irfan Nafi

    B Does fusion occur because you exceeded the strong force?

    When 2 protons fuse in a star, does the fusion rely on how strong the gravitational pressure is from the star so it gets past the strong force so the nuclei fuse or the temperature because of the pressure or both?
  23. Bill Myk

    I Strong Force and Wave function collapse

    Why does STRONG FORCE fail regarding complex structures of sub atomic particles when wave functions collapse @ entangled superpositions. Why does it not continue to function keeping the particles bound yet unentangled with the observed Eigenstate being it was originally binding such particles @...
  24. Surya97

    I Why do the fundamental forces have different ranges?

    How come gravity and electromagnetism have an infinite range, while the strong nuclear force dies out quickly? I understand that the weak force's bosons, the W+, W- and Z (neutral), have relatively large mass, and decay quickly, while the photon and the graviton (theoretical carrier of gravity)...
  25. Garlic

    A Strong force bremsstrahlung equivalent

    Are there strong interactional equivalents of synchrotron, bremsstrahlung and cerenkov radiation? Or for the weak/gravitational interactions? For example, will an accelerating bare quark emit gluons?
  26. nebulacollector

    What is the relationship between the Casimir force and the strong nuclear force?

    http://math.ucr.edu/home/baez/physics/Quantum/casimir.html http://abyss.uoregon.edu/~js/ast123/lectures/lec17.html The Casimir force is simply a pressure difference in the quantum foam exerting a force upon two plates, but is the strong nuclear force the same thing? Is it a pressure difference...
  27. Billmyk

    Superpositions and strong force

    I'm a bit confused now i understand that when one observes a particle for example @ Eigenstate A all its superpositions collapse because they are entangled with A which leaves them no longer entangled. My dilemma and maybe you can help me, is that If you observe a complex structure of sub...
  28. Anonymous Vegetable

    What is the reason for mass defect in a nuclide?

    I may be misguided here but to my understanding, separate nucleons have a higher mass altogether than the combined nucleus as the potential energy gained from being separated (in the field of the strong force) is being manifested in more mass. If this is true, and if it's not I'd like to know...
  29. Garlic

    Understanding the Residual Strong Force on Hadrons - Explained

    Hello everyone, Why does the residual strong force arise? Hadrons carry no net color charge, so why are they experiencing the strong force?
  30. Z

    Why is the Strong Force Responsible for Pi+ + Proton -> K+ + X?

    Please can you help, I have seen an exam question which asks which interaction is responsible for the following ... Pi+ + proton >>>>> K+ + unknown particle X The options for the answer include both the weak and the strong force. The actual answer is the strong force. What I would...
  31. 1

    How does protons has mass and not pions?

    hi, I've heard that protons has most of their mass from their electromagnetic and strong interactions between their quarks, but specifically, how does that make mass? and if so, what is intrinsic mass then? and pions has 2 quarks and strong and electro interactions, why doesn't it has mass...
  32. Einstein's Cat

    Particles with neutral charges but not affected by the weak or strong force

    Are there any particles which have a neutral electrical charge and are not affected by the weak or strong nuclear force? Thank you for your time and please excuse me if I'm being very ignorant!
  33. Yohanes Nuwara

    What is the entropy of weak and strong force?

    What is the entropy of weak and strong force? Can we determine their entropy? If so, I would like to know the formula of determining this. Thanks:wink:
  34. U

    Why is this decay allowed and another not?

    Consider ##\Sigma^0 \rightarrow \Lambda + \pi^0##. (Not Allowed) According to griffiths, this strong interaction is not allowed by 'Conservation of Energy'. I'm not sure why, as this simply shows an up and anti-up quark coming together, producing a gluon, where mass of gluon is mass of up and...
  35. S

    GAMSAT Strong Force Question: What Happens to Energy?

    I wasn't sure where to post this, but about a week ago, I sat a test called GAMSAT which has a science section comprising 20% physics, 40% chemistry and 40% biology. Physics isn't exactly my strong point, however, the developers cite needing only high school level understanding (I stopped...
  36. S

    The Nature of Strong Force: Explaining Its Cause and Effects

    Please explain how is exactly strong force caused, I've come across various answers but haven't yet received a complete answer. What is the nature of the strong force? P.S: If this is the wrong thread, Please RE-LOCATE and do not remove please. :)
  37. S

    My Confusion Regarding the Strong Force

    In an effort to clarify my question, allow me first of all to state what I believe I DO understand: All observed elementary particles are either fermions or bosons. Ignoring the Higgs boson (which gives other particles mass via the Higgs mechanism), there are four forces operating in the...
  38. A

    Strong force and beta function

    I heard that one of Euler's Beta/Gamma function identities models the strong force. I was just wondering how it did this. (This might be a stupid question) How do we measure the strong force, and how is it a function of two variables?
  39. B

    Quarkonium: General Information

    So I've been set a computational problem regarding applying the Shroedinger equation to quarkonium and I'm just trying to do some research around the subject because it's nothing like I've ever covered before and quite fascinating. There's quite a few questions that I can't find answers to...
  40. avito009

    The mass of the atom is due to the energy of strong force. So it is energy and not mass right?

    The mass of the nucleons (and, by extension, most of the visible universe) is caused by the energy stored up in the force field of the strong nuclear force. Please Explain this to me in layman's terms. I would appreciate the help. (I am being polite because phinds said so). How does the energy...
  41. N

    How strong is the strong force?

    I got to wondering about this the other day so I tried looking it up but I could not find anything. All j could find was that it had a maximum force of 10,00N. I tried to calculate the electrostatic force of a helium atom because if the strong force has to hold the atoms nuclei together jt has...
  42. Spinnor

    ψ in formula for strong force currents, how many components?

    In the ψ below, there are 4 components for the Dirac spinnor times three possible color states for a total of 12 components for ψ? Are there low energy, weak field limits of the above that allow us to consider classical color counterparts of electric current densities and electric charge...
  43. S

    Merging the strong force with the gravitational force

    has anyone tried to merge gravity and the strong force mathematically? The two seem very compatible--the gloun is the only vector boson capable of causing a force to be applied between two similarly charged objects. Isn't it likely that there is some kind of gluonic field, which behaves...
  44. P

    Analogy for magnetism in the nuclear strong force?

    Whenever people begin to explain the nuclear strong force, they relate it to electricity. I was wondering if color charges, besides also interacting with one another in a way that's analogous to electricity, can also interact in a way that's analogous to magnetism. I have asked some professors...
  45. 10Exahertz

    Calculating the Nuclear Strong Force?

    For an Ap Physics Homework assignment our teacher had us calculate the Nuclear Strong Force for a Helium nucleus with a diameter of 2 femtometers. However, the intention was to calculate the nuclear strong force by assuming that the nucleus is intact, in such a case the particles would not be...
  46. T

    Approximate the strong force between two protons.

    Homework Statement 2 protons in a Helium nucleus are separated by about 2x10^-15 m. Calculate the approximate magnitude of the strong force holding the 2 protons together.Homework Equations Electromagnetic force equation?The Attempt at a Solution Okay now I am thinking that the strong force is...
  47. A

    What is the difference between strong force and residual strong force?

    what is the difference between strong force and residual strong force ?what is its range?
  48. HakimPhilo

    What is the strength of the strong force?

    Hello everybody! :shy: What is the strength of the strong force between, for instance, a proton and a neutron separated by a distance on the order of femtometers (1fm and 2fm and 3fm) in Newton? Thank you in advance! ∞
  49. J

    Why would some particles not interact through the strong force?

    I've been thinking about dark matter, WIMPs and neutrinos, and why these particles would not interact with matter through the strong force. All massive particles interact gravitationally, all charged particles interact electromagnetically, (I don't fully understand the weak force, so I won't...