What is Strong interaction: Definition and 33 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.
The longer-range inter-nucleon force is not a direct result of the gluon field, but is indirectly affected by a quark-antiquark pair (meson).
If this ‘residual’ strong interaction between nucleons is mediated by a π-meson, then what is the maximum time period in which the interaction takes...
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##...
Is there any type interaction between neutron and matter other than strong interaction? When a neutron elastically or inelastically scattered, does the strong interaction still govern the whole process? Thank you!
Hi everyone,
I have the following question
When a positive pion interacts with a proton, a kaon can be produced, along with another strange particle, as shown in this equation
\pi^++\textrm{P}\longrightarrow \textrm{K}^++\textrm{X}
Circle the type of interaction shown...
Homework Statement
In electromagnetic interactions, the force carrier is the photon, and it interacts with anything which has electric charge. Electric charge can be represented by the integers on a single number line and photons themselves carry no electric charge.
(a) In the case of the...
I'm a high school student reading through a book on the discovery of the Higgs boson, and, among several other things, there's one part that I don't understand completely.
I understand that the Higgs field is what gives mass to lots of particles that would otherwise be the same without the...
In QFT, we can expand the propagator and obtain the diagrammatic expansion to build up the Green's function. If we have a hamiltonian of the type H = H_{0}+V, where V is the perturbation, we can build up the Feynman diagrams,and if we could build up all of them to infinite order, we would...
Homework Statement
(a)Draw feynman diagrams of upsilon meson. Why is decay to ##q\bar q## states suppressed? Explain why width for 4s is much wider.
(b) How do B mesons decay? Why is no other type of interaction possible? Draw feynman diagrams.
(c) Find the distance traveled by 1s and 4s.
(d)...
If you consider the ##\chi_0 ## with a mass of ## 3.4 GeV/c^2## meson, why doesn't it decay to a pair of charged leptons? Technically it is possible though the weak interaction (Z boson) or EM interaction, right?
Is it because it is so heavily suppressed because the strong interactions are...
Homework Statement
(a) Draw the feynman diagram for ##p \bar p \rightarrow## reaction.
(b) Find an expression for mass of the particle.
(c) Find an expression for number of ##\mu^{+} \mu^{-}## produced.
(d) Find an expression of ##n_{jj}## in terms of ##m_{inv}## and its spin.
(e) Deduce the...
Homework Statement
(a) Explain the results.
(b) Why is the cross section much higher? Suggest the dominant decay product pair.[/B]
Homework EquationsThe Attempt at a Solution
[/B]
Part(a)
For a centre of mass energy of ##170GeV##, you produce pairs of oppositely charged ##W^{\pm},W^{\mp}##...
The question is for which of the ##1P## meson states - ##1^{1}P_{1}, 1^{3}P_{0},1^{3}P_{1}, 1^{3}P_{2} ## ##D_{s}## states decaying to a ##1S## state is the decay: ##D_{s}**^{+} -> D_{s}^{+}\pi^{0} ## possible?
Solution
So the strong interaction conserves parity. Parity of meson is given by...
Hi everyone,
I have a simple and foolish question.
I want to compare the energy of a given mass (obviously e=mc2); let's say the energy of a hydrogen atom, with the energy that binds together the fundamental particles of that atom (strong interaction). I know that e=mc2 holds always true, and...
Dear all, this is my first thread in the forum.
I am trying to solve the following problem. it was given during a written exam at my university (many years ago) and I really would appreciate if someone will help me to solve it
1. Homework Statement
Show that if the hamiltonian of the strong...
Hello All,
I am quiet new to the subject, so if anybody can help me.
The four fundamental forces of nature, gravity, strong, weak,electromagnetism. Through weak force, all the electrons, protons and neutrons interact with each other. An attempt was made late in the 20th.century to unify...
Homework Statement
Homework Equations
This one has confused me,
I know that Baryon number has to be conserved so X has to be a baryon.
I can see how charge is conserved
The Attempt at a Solution
I know this is the strong interaction. Is it a collision?
Is that where the...
My understanding of colour so far is that if we had, say, a baryon with quark content uuu, we would need to invoke a new quantum number that would allow each quark not to be in the same quantum state to avoid violating the Pauli principle.
Now apparently this new quantum number is called colour...
hey,
i want to find the lowest order strong interaction feynman diagram for the following process:
\Sigma^{++}_c \rightarrow \Lambda^+_c \pi^+
the quark composition is:
\Sigma^{++}_c = (c u u) \ \Lambda^+_c = (c u d). \pi^+ =( \bar{d} u )
an image of a correct process is attached...
As we know:Gravitation is attractive force, electric force is attractive and repulsive force.
Weak and strong interaction are attractive or repulsive force?
I hope this is the right section for this topic...
I'm not a student of physics, I actually study engineering, and there's something I've been wondering for a while. I know - more or less - inside and out two of the four "forces" of the universe: gravity and electromagnetism. However, since I...
I am having some difficulty understanding the concept of colour charge.
I realize that protons and neutrons are made up of a different number of quarks, and this is how they have the charges +1 and zero.
I then realized that different quarks have color charge and that in a hadron (protons...
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...
I have a proton and an antiproton scattering, via a pion exchange.
The matrix element has the form:
M=g*(\bar{u}_{1}\gamma ^{5}u_{2})\frac {1} {q^2-m^2}( \bar{v}_{1}\gamma ^{5}v_2)
Wher g is my coupling constant, and q the 4-momentum of the pion.
The problem is that when I compute the...
Hello,
Does anyone know why in pionic hydrogen the strong interaction should be attractive whilst in kaonic hydrogen it is repulsive. I have heard it is something to do with a sub-threshold resonance but nothing more.
Thanks
Sham
In the Residual Strong Interaction, energy and momentum are exchanged not through gluons but through exchange of quarks, for example in the soft hadronic scattering of a pi + and proton. Is the interaction mediated by a single meson or by two quarks, and if the latter doesn't this violate quark...
I have a problem in understanding the dependence by isospin of strong interaction.
In this potential one have a lot of operatorial terms which include central, spin-spin, tensor force, spin-orbit terms, and all this four terms multiply by a factor isospin-dependent (tau_i dot tau_j).
I don't...