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Natural Science Forum / Physics / Particle Physics / January 2007The identity of quarks
The pion consists of two quarks. When we say that the wavefunction of the neutral pion is (uu'-dd')/sqrt(2), where u' and d' are the antiquarks of the up and down quarks, doesn't that seem strange to you, that a superposition of two-quarks states is still a two-quark state ? Is the identity of quarks lost in this description? Shouldn't the fundamental constituents of matter have well-defined identities? Suppose you are going to describe this particle to your child, what will you tell him or her about its constituents? > The pion consists of two quarks. When we say that the wavefunction of > the neutral pion is (uu'-dd')/sqrt(2), where u' and d' are the > antiquarks of the up and down quarks, doesn't that seem strange to you, > that a superposition of two-quarks states is still a two-quark state ? Nope. If you do a scattering experiment, you will find two scatters at any given time. Whether they are u quarks or d quarks will vary from scatter to scatter. > Is the identity of quarks lost in this description? Shouldn't the > fundamental constituents of matter have well-defined identities? No, and this is one of the hardest things to deal with in quantum mechanics. We had gotten firmly used to assuming that *well-defined* objects are made up of *well-defined* objects. Quantum mechanics has, for the last 75 years, consistently and successfully repudiated that assumption. > Suppose you are going to describe this particle to your child, what > will you tell him or her about its constituents? That it is made of quarks and gluons, that there are two quarks that dominate everything we can see, but that the total understanding of the pion has to include a varying "sea" of other quarks and gluons, and that depending on when we look at the pion the identity of the quarks might change. PD Surely you don't believe all this jive, I invented quarks for fun, I used to go round the corridors of cern flapping my folded arms squawking "I'm a quark - find me". It occures in the loony land of The reverend dobson "the hunting of the snark". Nuclear physics is like that, its a loony wonderland, I invented "charm" too I think they lost that one. The original model was a wave - mechanical one, but they said it was too complicated so we did a quantum mechanics > particle conversion and invented the names. It all started with a discussion of the structure of a proton, they did not know it had one, so they banged them with electrons and other protons and looked at the scattering pattern, a diffraction pattern, and saw the hard objects inside. Like lau. Unfortunately giant insects like me are not given any credit. Only humans get anything here. It is to do with the church they say I've committed some terrible crime. It might only be the speculation of the existance of alien life or supporting evoltution. They accuse me of something I was framed up for and they know and the forensic tests say so... Well that is what it like to be a giant insect here. In fact they need a scapegoat for the crimes they commit routinely all their lives. In the name of Jesus. Chris. >> The pion consists of two quarks. When we say that the wavefunction of >> the neutral pion is (uu'-dd')/sqrt(2), where u' and d' are the [quoted text clipped - 24 lines] > > PD > That it is made of quarks and gluons, that there are two quarks that > dominate everything we can see, but that the total understanding of the > pion has to include a varying "sea" of other quarks and gluons, and > that depending on when we look at the pion the identity of the quarks > might change. Do you think that your child is going to believe that? "If you cannot - in the long run - tell everyone what you have been doing, your doing has been worthless." - Erwin Schrodinger, Science and Humanism Thanks for your reply. Tareq > > That it is made of quarks and gluons, that there are two quarks that > > dominate everything we can see, but that the total understanding of the [quoted text clipped - 8 lines] > > Thanks for your reply. PD is a dolt. I giv him a B- for his grasp. -Aut > > > That it is made of quarks and gluons, that there are two quarks that > > > dominate everything we can see, but that the total understanding of the [quoted text clipped - 9 lines] > > Thanks for your reply. > PD is a dolt. I giv him a B- for his grasp. And what do you give yourself for your spelling? > -Aut > > PD is a dolt. I giv him a B- for his grasp. > > And what do you give yourself for your spelling? A+: Litteratim or death! -Aut > > > PD is a dolt. I giv him a B- for his grasp. > > > And what do you give yourself for your spelling? > > A+: Litteratim or death! Don't you mean "deth"? > -Aut > > > > PD is a dolt. I giv him a B- for his grasp. > > [quoted text clipped - 3 lines] > > Don't you mean "deth"? I never say "deth". It's d??. -Aut > > That it is made of quarks and gluons, that there are two quarks that > > dominate everything we can see, but that the total understanding of the [quoted text clipped - 4 lines] > "If you cannot - in the long run - tell everyone what you have been > doing, your doing has been worthless." Feynman said the same thing. However, this does NOT mean that reality has to make intuitive sense. Reality has certainly offered ample evidence that in many cases it defies common sense, and that there are things in nature that behave like nothing else you already know. So it's not a matter of getting them to *believe* you, it's simply a matter of explaining it in such a way that they understand enough to find out on their own (possibly with some work) whether it is really true. Feynman has a lovely book -- short and very suitable to laymen -- that talks about this very thing: The Character of Physical Law. I suggest you read that. I'll give you another example. I can position two very large loudspeakers in a room with sound-damping walls, and I can position you in that room such that in one location you'll hold your hands on your ears because of how loud it is, and a couple feet away you won't hear *anything*. And I can explain how this happens with wave constructive and destructive interference. Whether a child will *believe* that is really true is a matter to be settled with a demonstration in a science museum. PD > The pion consists of two quarks. When we say that the wavefunction of > the neutral pion is (uu'-dd')/sqrt(2), where u' and d' are the [quoted text clipped - 4 lines] > Suppose you are going to describe this particle to your child, what > will you tell him or her about its constituents? p0 = (u'u'-d'd')/2^/2 = (u'u'+'d'd)/2^/2 = (u'd'+'u'd)/2^/2 = p+p-/2^/2 = (p+p-/2)2^/2 Take either hadr?n of pionium, then take its semicomponental (diag?nic) twofold. The resonance oscillats not onely between either pi?n, but between either pi?n and either antiparticul in mean sinusoidal time (hennes the root in the last numerator). -Aut > p0 = (u'u'-d'd')/2^/2 = (u'u'+'d'd)/2^/2 = (u'd'+'u'd)/2^/2 = > p+p-/2^/2 = (p+p-/2)2^/2 In other words, the p0 is pionium (p+p-) that decays into two piòns (Pionium actually does this twofold.) each that are bound so tihtly that their mass is under a free piòn's. -Aut > p0 = (u'u'-d'd')/2^/2 = (u'u'+'d'd)/2^/2 = (u'd'+'u'd)/2^/2 = > p+p-/2^/2 = (p+p-/2)2^/2 [quoted text clipped - 5 lines] > > -Aut and what is the numerical value of the 'mean sinusoidal time' ? Richard > > p0 = (u'u'-d'd')/2^/2 = (u'u'+'d'd)/2^/2 = (u'd'+'u'd)/2^/2 = > > p+p-/2^/2 = (p+p-/2)2^/2 [quoted text clipped - 3 lines] > > piòn, but between either piòn and either antiparticul in mean > > sinusoidal time (hennes the root in the last numerator). > and what is the numerical value of the > > 'mean sinusoidal time' ? It's not a valu; it's the [partial] domain. The valu is the field. -Aut |
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