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 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 $6×10^{39}$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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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 $��_S$ 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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How well does the strong nuclear forces cancel out over large distances?
Motivation: I was wondering if by any chance gravity could not be a "non-force", but instead be a residual of all other forces that is generated when you put together a bunch of particles with slight ...
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Why is it called the "quenched" approximation in QCD?
The quenched approximation of QCD (or other QCD-like theories) is when you basically ignore fermion loops, i.e. fermions are non-dynamical fields. For quantities that do not involve external fermion ...
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Does nuclear binding energy concern nuclear force or EM force?
From my understanding, binding energy is the energy required to separate all nucleons in a nucleus an infinite distance away from each other. I cannot tell whether this ignored the effect of one of ...
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Nuclear force and binding energy
What i read about binding energy is that it is the energy released when nucleus is formed due to the attraction of the strong nuclear force between nucleons. But even after the nucleus is formed, the ...
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Does more binding energy between nucleons in different elements as they have more nucleons mean the nuclear force between them is stronger?
My picture of fission is that the nuclear force is the centripetal force and the electrostatic is the centrifugal one and when some energy helps the electrostatic force the nucleus reacts with fission....
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Simple "toy-model"-like explanation of quark confinement (QCD) and accompanying math
I have a qualitative understanding of quantum chromodynamics within nucleons and between nucleons, but I do not understand the math behind some of the physics like quark confinement.
What is the math ...
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Equations of motion of classical chromodynamics with Yang-Mills theory
I am currently reading a paper about classical chromodynamics:
https://arxiv.org/abs/hep-th/0607203
However I have problems understanding equation (2) and (4)
(2):
\begin{equation}
F_{\mu \nu}= \...
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Why can we only measure the electromagnetism and gravitation in real life, and not the nuclear forces?
Why can we only measure the electromagnetism and gravitation in real life, and not the nuclear forces? All our senses are explained with EM forces and pressure values directly and heat transfer.
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What’s lacking in our understanding of the strong interaction?
As far as I’m aware, our understanding of the strong interaction and strong nuclear force is pretty good. We can explain how particles move and stick together with good models. But from what I can ...
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Understanding interaction between two quarks
Two protons and two electrons repel each other as they have same charge. Protons and electrons attract each other since they are oppositely charged.
A single proton is made up of two up and one down ...
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Are Feynman diagrams equivalent when gluons are emitted from different quarks?
3rd year physics undergrad here. I am new to particle physics.
We were asked to give the lowest order Feynman diagram of this reaction.
$$K_1^+(1400) \to K^+ \pi^+\pi^- $$
Now I came up with not ...
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Understanding the Coulomb term in the semi-empirical mass formula
Here's a passage I am not understanding:
The tendency to an excess of neutrons at large mass numbers is a Coulomb repulsion effect. Because a given nucleon interacts with only a small number of its ...
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Are Yukawa interaction theories still in use?
As is commonly known, the Yukawa interaction (scalar/pseudoscalar) was used to describe the old-school, pion mediated, strong force, long before the discovery of quarks.
The theory has been proven to ...