Questions tagged [strong-force]

The strong force or interaction is responsible for the confinement of quarks inside hadrons and the binding of nucleons inside a nucleon, and it is described by the gauge theory of QCD. It provides most of the mass of ordinary matter, which is dominated by the nucleons, proton and neutron: over 99% of the mass of these is attributable to the strong-force field energy. Use where technical details of QCD are not warranted.

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How can I visualize the oxygen nuclear charge density?

Oxygen has 8 protons and 8 neutrons. Based on the nuclear shell model, protons should pair with anti-parallel protons to create singlet spin states, and neutrons should similarly pair with anti-...
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How can the strong nuclear force (QCD) be considered to violate chirality, but not parity?

Chirality is related to parity, correct? It is a form of 'parity'? So, How can the strong force violate chirality symmetry, but only the weak force violates parity symmetry? I am confused about the ...
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What mechanism gives mass to gluon balls? [duplicate]

Glueballs are hypothetical, real (non-virtual) particles made up of gluons, the particle of the gluon field that interacts with quarks. The gluons have a color charge themselves and they can form a ...
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How do virtual particles cause an attraction? [duplicate]

How do virtual particles such as photons cause a force between particles such as an attraction between protons and electrons?
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Why does the binding energy per nucleon rise as the nucleon number rises, then go down again, with nuclei heavier than iron? [duplicate]

As the strong nuclear force is a short range force, and as it is way stronger than Coulomb force, Lumen Learning answered my question as follows: “for low-mass nuclei, the nuclear attraction dominates ...
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Is nuclear force always attractive?

I read in my high school physics's textbook that nuclear force holds the nucleus. Is the nuclear force another name for the strong force? If it holds the nucleus it should be attractive. Am I right?
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Does the nuclear interaction favour aligned or anti-aligned spins?

My particle physics lecture notes seem to have contradictory statements. Firstly they argue that p-n is stable while p-p and n-n are not because the nuclear interaction favours spin alignment (and by ...
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Does pionium decay in massless QCD?

The bound state of ${\pi}^+ {\pi}^-$ is called Pionium. Is Pionium an Electromagnetic bound state or a Strong Force one? then Why? Does such a bound state last forever if one works in QCD with ...
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Is electric potential energy responsible for energy release in nuclear fission and nuclear potential energy in fusion? What if elec. force not exist?

It was my doubt and I thought it may be electric potential energy which is responsible for energy release in nuclear fission and by bombarding neutron we only provide energy to nucleons to cross ...
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Low energy strong coupling asymptotic

The low-energy behavior ($Q^2<\text{1GeV}^2$) of the strong interaction coupling constant predicted by LFHQCD, $\alpha_S = \pi \exp(-Q^2/4\kappa^2) $, where $\kappa=M_\rho/\sqrt{2}$, is in ...
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Do the “$SU(3)$ colors” live in a 3-dimensional vector space?

Previously I asked a question about the visualized colors: Do the "colors" live in a 3-dimensional vector space? (My earlier question is unfortunately closed) Now I like to ask the “$SU(3)$ ...
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How can the graviton spin-2 string have emerged from the strong interaction, mediated by spin-1 gluons?

The origin of string theory can be traced back to 1969: String theory was first studied in the late 1960s as a theory of the strong nuclear force, before being abandoned in favor of quantum ...
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How does the strong force increase in attraction as particles move farther away?

I have heard that the strong force can be imagined similar to a rubber band, where the farther you extend the ends, the harder they pull themselves back together. My question is how? From what it ...
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Can strong and weak “forces” manifest in Newton Units?

The Newton unit ($\text{N}$) is a unit of force on a macroscopic scale: $$1\text{N} = 1 \text{kg m/s}^2.$$ Gravity has so-called the gravitational forces (such as shown in the Newton theory of ...
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What is the equation for the non-constant coupling $\alpha_s$ for the strong force?

I wanted to ask the question Is there an equation for the strong nuclear force? but someone already has. The top answer gives $$V(r) = - \dfrac{4}{3} \dfrac{\alpha_s(r) \hbar c}{r} + kr$$ It is ...
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Why is the alpha particle in alpha decay considered to be in a potential well?

I understand that when modelling alpha decay, it is useful to consider the $\alpha$ particle as being preformed, in a region confined to the daughter nuclei. I also understand that the term $V_{0}$ ...
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Why is residual strong force needed?

I was wondering why the residual force was needed to hold nucleons together? If the net charge resides on the surface and acts perpendicular to the surface (page I found, though not about nuclei), how ...
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Behaviour of Nuclear Force

If nuclear force is attractive, then why the nucleons don't collide with each other? I think about this, but do not get any proper answer?
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Can Montonen-Olive duality be used for studying $\mathcal{N}=4$ SYM at strong coupling? If not, why not?

It's all in the title. To be more complete, the following is stated in the preamble of the Wikipedia article about S-duality: One of the earliest known examples of S-duality in quantum field theory ...
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What would happen if the attractive force at work in the nucleus had been equal in magnitude to the repulsive electrostatic force between the protons?

I am just starting with radioactivity and I came upon this statement: "Since the nucleus is stable, this means that there is some attractive force at work in the nucleus and that its magnitude ...
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Like quark baryons

Why aren't there particles like neutrons or protons but with 3 up or 3 down quarks, instead of 2 up/1 down or 2 down/1 up. Does there have to be 2 different types of quarks for the strong force to ...
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Is there any formula for strong and weak nuclear force? [duplicate]

As we know, there is an equation for gravitational force $$F = \frac{Gm_1m_2}{R^2}$$ While for electromagnetism, it is $$F = q(E + v × B)$$ So is there any true formula to find the weak and strong ...
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Do hadrons have color moments?

Hadrons have electrical moments since they are made up of both positive and negative charges. Water molecules have dipole moments for the same reason even though they are electrically neutral. Since ...
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Strong and Weak Interactions [closed]

How do I determine whether an interactions is strong or weak if what i've been given is just the particles and the type of reaction: Determine whether the following are strong or weak interactions? a ...
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How should a *good* nuclear theory explains spin-orbit coupling?

Under the framework of the independent-particle model in nuclear physics, the general form for the Hamiltonian is given by \begin{equation}\label{1} H=\sum_{k=1}^{A}[T(k)+U(k)]+\left[\sum_{1=k<l}^{...
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Does the strong force explain the binding energies of nuclei?

Does the current theory of the strong force accurately predict the Nuclear Energy Binding Curve? See definition of this curve on Wikipedia.
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Understanding $\rm SU(3)$ Gauge Invariance Through a Perturbation Theory

Here I am modifying the field theory approach, since I never taken a course on Quantum Field Theory. I am exploring Gauge Invariance in $\rm SU(3)$ by the following approach (which technically is ...
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If the Strong Nuclear Force is 6x10^39 times stronger than Gravity, how is a black hole able to tear nuclei apart?

Furthermore, would a black hole be able to tear apart a quark pair? Would there be a difference in tidal forces on a scale that small?
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Is isospin magnitude $I$ conserved? [duplicate]

Here is a table of isospin conservation in certain reactions. It is often loosely stated that 'isospin is always conserved in strong interactions', but it is never clear whether they mean total ...
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Black holes, no-hair and color charge

No-hair theorem asserts that black holes can be defined by only their mass, angular momentum and electric charge. Do black holes treat strong force differently, ie can black hole have color charge? ...
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Pauli exclusion principle: why does it imply that $Z\approx N$ in stable nuclides with $A<40$?

I have read that when representing the possible nuclides in the $(Z,N)$ plot, the stable nuclei located on the line $N=Z$ for $A<40$, and that this is due to the Pauli exclusion principle. I have ...
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Derivation of interaction potentials of fundamental forces

In Gauge theory of weak interactions by Greiner and Müller, they show the following superb comparison of the interaction potentials between particles as a function of separation: I have never seen ...
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Do the strong and weak nuclear forces also travel at the speed of light?

Among the four fundamental forces, it is now pretty well-known that the electromagnetic and gravitational ones travel at the speed of light. How about the other two (strong and weak nuclear forces)? ...
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Why do I get different answers for the comparison for the strong force to gravity?

In many data sets comparing the fundamental forces, you can find the relative strength of them compared to each other specifically comparing gravity to the strong force. Is it because the strength of ...
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Can we infer from weak isospin symmetry the existence of sub-quark particles?

In the old theory of the strong force, where the strong force was thought to be conveyed by massive mesons (pions), as one can read here: The discovery of the neutron in 1932 revealed that atomic ...
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How to prove the equivalence of two definitions of hypercharge?

Before introducing top bottom and charm quarks,Strong Hypercharge is defined in the following two ways--- $1.\,\,\,Y=B+S$ where $Y,B,S$ are the hypercharge, baryon number and strangeness respectively. ...
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Everyday repercussions of nuclear forces change

I'm pretty sure that, if all of a sudden gravity just disappeared (someone just set $G=0$ by turning a magical knob) we would notice immediately, starting to float in the air and a bunch of other ...
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How does the mere movement of gluons keep quarks together?

You know the strong force (the one that keeps quarks together). Well it works by exchanging gluons right? So how does that force keep the quarks together? I mean you can imagine that process as three ...
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What happens when one separates a quark-antiquark pair?

in particular, if the distance is more than about 1 fm?
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Can the ratio of gravitational force to Coulomb repulsion force in the nucleus be increased by adding neutrons? How many?

As you know, the ratio of gravitational force to Coulomb repulsion force between two protons is very small. This means that the source of nuclear stability cannot be the force of gravity. Can some ...
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How can I build up my knowledge in particle physics to the level that I can calculate the path of elementary particles in a perfect vacuum?

I have to write a research paper (don't know the exact english translation) for school. The question I want the paper to answer/discuss is: 'Can the universe be predicted at sub-atomic level?' The ...
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What is it about the mechanism for the strong force which creates a force?

So as I understand it, the mechanism for the strong force is that quarks emit/exchange gluons. Similarly, quark-anti-quark pairs are what pass between nucleons in an atom causing them to stick to each ...
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Eight gluons, what are the properties of two of them?

If there are 8 gluons, and 6 of them can be represented as a color/anticolor pair (red/antiblue for example), that leaves 2 "other" gluons. How do these two gluons differ from each other? ...
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What is the physical explaination for the presence electrostatic forces (just like we have for gravity)?

We know that gravity is caused by the curls and warps in spacetime fabric. Does a similar explaination exist for electrostatic forces? What if there are two particles separated hundreds of kilometres ...
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Doesn't the neutron's lack of an electric dipole moment conflict with the concept of baryons having a radius?

The proton radius puzzle appears to one of the more widely known unsolved problems in physics, but doesn't it point to a much deeper issue? Nearly all of a baryon's observed mass can be attributed to ...
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How is strong coupling constant related to cross section?

I've been looking through different Pdfs /articles on strong coupling constant and nearly all of them involve cross section, I've understood what cross section is but not how is it connected to ...
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How is strong coupling constant measured through deep inellastic scattering (DIS)?

is deep inelastic scattering a process? and how is it (DIS) used to measure strong coupling constant? the traditional method of measuring $α_S$ in deep inelastic scattering is from the strength of ...
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Change of flavour in strong interactions?

Sorry if this question has been asked already but after researching I have found that quark flavour is not changed in the strong interaction. This confused me because how can a down and anti down ...
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Calculating strong coupling constant $\alpha_s$

I'm trying to find out how to calculate the value of strong coupling constant. but haven't found any exact answer, all I get is reference to perturbation theory. is there any exact defined formula to ...
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The charge of an electron is a constant. In any case? [closed]

Since Millikan it is obvious that the charge of the electron can be measured as a result of the force exerted by an external electric field. What we get in detail is the charge from the excess of ...

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