http://en.wikipedia.org/wiki/Proton_spin_crisis
The Proton Spin Crisis The *proton spin crisis* (sometimes called the "proton spin puzzle") was a theoretical crisis precipitated by an experiment in 1987 which tried to detect spin configuration of the proton. The experiment was carried out by the European Muon Collaboration (EMC). Physicists expected that the quarks carry all the proton spin. However, not only was the total proton spin carried by quarks far smaller than 100%, these results were consistent with almost zero proton spin being carried by quarks. This surprising and puzzling result was termed the "proton spin crisis". The problem is still considered one of the most important unsolved problems in physics. Background A key question is how the nucleon's spin is distributed amongst its constituent partons (quarks and gluons). Physicists originally expected that quarks carry all of the nucleon spin. According to quantum chromodynamics, the proton is built from two *up* and one *down* quark, gluons and possibly additional pairs of quark and anti-quark.] <http://en.wikipedia.org/wiki/Proton_spin_crisis#cite_note-3> The ruling assumption was that since the proton is stable, then it exists in the lowest possible energy level. Therefore, it was expected that the quark's wave function is the spherically symmetric s-wave with no spatial contribution to angular momentum. The proton is, like each of its quarks, a spin-1/2 particle. Therefore, it was assumed that two of the quarks have opposite spins and the spin of the third quark is parallel to the proton spin. The experiment In this EMC experiment, a quark of a polarized proton target was hit by a polarized muon beam, and the quark's instantaneous spin was measured. In a polarized proton target, all the protons' spin take the same direction, and therefore it was expected that the spin of two out of the three quarks cancels out and the spin of the third quark is polarized in the direction of the proton's spin. Thus, the sum of the quarks' spin was expected to be equal to the proton's spin. However, it was found in this EMC experiment that the number of quarks with spin in the proton's spin direction was almost the same as the number of quarks whose spin was in the opposite direction. This is the proton spin crisis. Similar results have been obtained in later experiments. Recent work A 2008 work shows that more than half of the spin of the proton stems from the motion of its quarks, and the missing spin is produced by the quarks' spatial angular momentum] <http://en.wikipedia.org/wiki/Proton_spin_crisis#cite_note-5> This work uses relativistic effects together with other QCD properties and explains how they boil down to an overall spatial angular momentum that is consistent with the experimental data. This opinion is more recently preempted by the recent article referenced earlier in the thread. The take away: nobody really knows where the protons spin comes from yet. <Snip> However, using more recent RHIC results, Daniel de Florian of the University of Buenos Aires, Argentina, and his colleagues find a nonzero gluon polarization. More data is still needed at low momentum, but the current best fit suggests that as much as half of the proton’s spin comes from gluon spins >EndSnip> On Mon, Jul 7, 2014 at 8:21 PM, Axil Axil <[email protected]> wrote: > It is my contention that one of the many mechanisms of magnetic based LENR > reactions is that photons (magnetic) can pump energy into the > proton(and/or neutron) to the point where gluons in the proton(s) and/or > neutrons(s) will get to and surpass an energy saturation level. At that > point of saturation, these *Hadron(s)* will form a gluon/quark plasma > from which a new element will reform upon cooling (energy transfer back to > the magnetic soliton). > This mechanism is one of the most energy intensive LENR reactions and is > only seen in the Ni/H reactor. > > I believe that this contention is new physics beyond the standard model. > > > > > > On Mon, Jul 7, 2014 at 7:42 PM, Axil Axil <[email protected]> wrote: > >> From the referenced article: >> >> <Snip> >> >> The quarks have spin 1/2, so physicists originally assumed that two of >> the quarks were in opposite alignment (cancelling their spin), leaving one >> unpaired quark to give the proton spin. However, measurements of >> muon-proton collisions found only a quarter of the proton’s spin comes from >> quark spins. The rest has to come from gluon spins and/or the orbital >> motion of quarks and gluons inside the proton. >> >> <EndSnip> >> >> I referenced this article to show that gluons have spin and/or can >> produce spin. >> >> I believe that the standard model doctrinaire on gluon interactions that >> gluons can not interact with photons. >> >> I don't understand how a gluons can demonstrate magnetic properties(spin) >> and at the same time be unable to interact with photons. >> >> However, this paper: >> >> Exclusive Physics at the Tevatron >> shows photon/gluon interactions: >> >> http://arxiv.org/pdf/1006.0204.pdf >> >> >> On Mon, Jul 7, 2014 at 6:03 PM, <[email protected]> wrote: >> >>> In reply to Axil Axil's message of Sun, 6 Jul 2014 13:59:19 -0400: >>> Hi, >>> [snip] >>> >http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.113.012001 >>> > >>> >Gluons Chip in for Proton Spin >>> >>> No, it just means they rotate. The magnetic field would come from the >>> rotation >>> of the quarks. >>> >>> > >>> >It looks like polarized gluons produce most of the spin of the proton. >>> That >>> >means that the gluons are magnetic entities. >>> > >>> >A magnetic field applied to the proton could disrupt the polarization of >>> >the gluons and therefore the strong force that keeps protons and >>> neutrons >>> >together in the nucleus. >>> > >>> >There is an intimate relationship between the strong force, magnetic >>> force, >>> >and the gluon that might underpin LENR reactions at the most basic >>> level. >>> > >>> >. >>> Regards, >>> >>> Robin van Spaandonk >>> >>> http://rvanspaa.freehostia.com/project.html >>> >>> >> >
