gib65 Posted December 5, 2007 Posted December 5, 2007 I heard that the strong force which holds the quarks together in protons and neutrons is unbreakable. That is, one cannot tear the quarks in, say, a proton apart no matter how hard one tries. Is this true? If it is, then how did scientists ever figure out that protons and neutrons were made of quarks (AFAIK scientists figure out what a particle is made of by breaking it apart in an accelerator)?
thedarkshade Posted December 5, 2007 Posted December 5, 2007 I think there is something tinnier that quarks, so in a way, they're seperable! I just don't remember the name!
Fred56 Posted December 5, 2007 Posted December 5, 2007 Phew, for a sec there I thought this one was about a religious group... The strong force is asymptotic. It gets stronger as quarks "try" to leave their bound configuration, so they get "pulled back" (just like in that movie). The force is weakest at very small ranges (inversely asymptotic, I guess). The discovery has to do with scattering experiments and deflection angles. There are some good explanatory articles in earlier SA editions -the 80s-90s ones. Sorry, can't give you any better refs. just now.
swansont Posted December 6, 2007 Posted December 6, 2007 The strong force is asymptotic. It gets stronger as quarks "try" to leave their bound configuration, so they get "pulled back" Which means that you end up adding enough energy to create a quark-antiquark pair before you can separate the quarks, so you get mesons ejected from the interaction.
vincent Posted December 7, 2007 Posted December 7, 2007 The strong force is asymptotic...force is weakest at very small ranges (inversely asymptotic, I guess). I think you mean "asymptotically free".
elas Posted December 7, 2007 Posted December 7, 2007 swansont Which means that you end up adding enough energy to create a quark-antiquark pair before you can separate the quarks, so you get mesons ejected from the interaction. What happens to the mesons?
Riogho Posted December 8, 2007 Posted December 8, 2007 The quarks are bound together in a hadron by what scientists have deemed the 'colour' force. It has absolutely nothing to do with visible color, but then against electricity isn't really positive and negative, it is just how we choose to see it. Anyway, inside the hadron (proton for example), you have 3 quarks. Each one has a different colour, there are 3 different colours, these are Red, Green, Blue. Each one attracts the other for some odd reason. The thing that is strange about it is that the farther away the quarks are the stronger the force between them is. Unlike the other forces we readily accept, it's not the inverse-square of the distance, it actually gets STRONGER. I like to think of it this way: Let's say you and a pretty girl are all attatched, and you love each other a lot, eh? But of course you have a fight, and you decide you 'need your space'. We all know the phrase, 'distance makes the heart grow fonder'. So the longer you are away from her (and farther), the more you miss her, and want her back. It works that way with Quark Love. The farther they get away, the stronger the force is. That is why there is such a thing as 'quark confinement' which simply means we will never observe a lone quark, because they are always paired with another one. Now, we know that the proton is a composite particle because when we fire charged particles at let's say, a hydrogen nuclei, we can shoot the particles one at a time in a straight line, and they will bounce off in different directions, which give the illusion that the proton isn't evnely charged all the way around (it isn't exactly +1 all the way around as previously thought), that is why we came up with the idea of 2 +2/3 quarks and 1 -1/3, to explain the scattering. Of course, this is super-laymans terms and a lot has been left out, so don't kill me if I missed anything
Fred56 Posted December 8, 2007 Posted December 8, 2007 you mean "asymptotically free". Can you explain this term? Without using QCD as an example?
Riogho Posted December 8, 2007 Posted December 8, 2007 Quarks come closer to each other when the energy increases, so the interaction strength decreases with energy. This property, called asymptotic freedom, means that the beta function is negative. On the other hand, the interaction strength increases with increasing distance, which means that a quark cannot be removed from an atomic nucleus.
Mr Skeptic Posted December 8, 2007 Posted December 8, 2007 I thought that the strong force's strength first increased with distance, and then decreased with distance. Otherwise everything would be neutron stars.
insane_alien Posted December 8, 2007 Posted December 8, 2007 it increases to a certain distance then drops off to near zero not long after the peak.
swansont Posted December 8, 2007 Posted December 8, 2007 I thought that the strong force's strength first increased with distance, and then decreased with distance. Otherwise everything would be neutron stars. The strong force is one level up, so to speak — the force between baryons. Quarks interactions are described by the "color force."
elas Posted December 9, 2007 Posted December 9, 2007 it increases to a certain distance then drops off to near zero not long after the peak. This is the way all natural fields operate. Within the field nucleus the force increase with distance; outside the nucleus the force decreases with distance. Quarks are in the field nucleus, electrons and planets are in the field shell. Think of a Zero Point with a fixed quantity of force, the more that is extracted the less there is at the ZP until the ZP reaches zero. Further field extension involves 'drawing down' on the quantity of force already extracted; it therefore grows weaker with distance. Either side of the maximum force the force decreases (towards the ZP and towards the surface) to maintain a balance between the field nucleus and field shell forces; acting in opposite directions.
Severian Posted December 10, 2007 Posted December 10, 2007 it increases to a certain distance then drops off to near zero not long after the peak. I wouldn't put it like that. QCD strength always increases with increasing distance. This is often likened to an elastic string. But when you get far enough away there is so much energy in the binding that you can make a quark-antiquark pair from the binding energy. The string snaps.
elas Posted December 10, 2007 Posted December 10, 2007 Severian I wouldn't put it like that. QCD strength always increases with increasing distance. This is often likened to an elastic string. But when you get far enough away there is so much energy in the binding that you can make a quark-antiquark pair from the binding energy. The string snaps. Using this Standard Model explanation results in four quarks by stating that energy is an entity that is self multiplying. Why isn't space packed full of quarks? Surely it would be more practical to propose that gravitons or photons are are converted into quarks by vacuum action, when two quarks separate. (Conserving the number of elementary particles and their contents).
insane_alien Posted December 10, 2007 Posted December 10, 2007 Using this Standard Model explanation results in four quarks by stating that energy is an entity that is self multiplying. Why isn't space packed full of quarks? Surely it would be more practical to propose that gravitons or photons are are converted into quarks by vacuum action, when two quarks separate. (Conserving the number of elementary particles and their contents). care to show us how you arrived at that conclusion? feel free to show the mahematical model you used as well.
Mr Skeptic Posted December 10, 2007 Posted December 10, 2007 I wouldn't put it like that. QCD strength always increases with increasing distance. This is often likened to an elastic string. But when you get far enough away there is so much energy in the binding that you can make a quark-antiquark pair from the binding energy. The string snaps. Are you talking about the strength of the force increasing with distance, or just the energy?
Severian Posted December 14, 2007 Posted December 14, 2007 Using this Standard Model explanation results in four quarks by stating that energy is an entity that is self multiplying. The energy is conserved, as it always must be. It is transfered from potential energy (in the force) to mass-energy (in the new particles) Why isn't space packed full of quarks? Because there isn't enough energy. When you separate the quarks far enough, there is enough energy to make a quark anti-quark pair, but they will then snap back (converting the remaining potential energy to kinetic energy) and form two colorless mesons. Surely it would be more practical to propose that gravitons or photons are are converted into quarks by vacuum action, when two quarks separate. (Conserving the number of elementary particles and their contents). Clearly it would be more efficient if we could explain all the forces using a photon, but unfortunately this doesn't work. We need to have a particle which couples to itself to explain the behaviour of the strong interaction as we change distance. The photon doesn't couple to itself (it is neutral) but the gluon does. Are you talking about the strength of the force increasing with distance' date=' or just the energy? [/quote'] Both.
elas Posted December 14, 2007 Posted December 14, 2007 Severian Clearly it would be more efficient if we could explain all the forces using a photon, My submission on particle structure has been transferred to 'Speculations' so it would be improper for me to raise the subject here. However I find your reply interesting as it points to statements I shall need to deal with in any future revision. I am particularly interested in the above extract and would ask you to explain why 'a photon' why not a particle with 'charge'? I ask this because all my work is based on charged particles, I can offer an explanation of photon actions in words, but cannot find any way of including them in the mathematics (i.e. defining them in terms of potential or rest energy, and mass).
Severian Posted December 15, 2007 Posted December 15, 2007 I am particularly interested in the above extract and would ask you to explain why 'a photon' why not a particle with 'charge'? I am not quite sure what you are asking. The fact remains that the electromagnetic interaction gets weaker with distance while the strong interaction gets stronger with distance. In the Standard Model, this is predicted by the fact that the electromagnetic mediator (the photon) has no self coupling (is not charged) while the strong interaction mediator (the gluon) does have a self coupling (it is colored).
elas Posted December 16, 2007 Posted December 16, 2007 Severian In the Standard Model, this is predicted Thanks for your reply. I am not going to introduce my work into this forum, but will use your reply on my own forum submission within a few days.
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