On the Wikipedia proton-to-electron mass ratio article you can read that the proton mass is composed primarily of gluons, and of quarks. Since we know that a neutron is made up of an up quark and two down quarks and a proton is made up of two up quarks and a down quark, we can write the following quark equation; From this you can see that one the original up quark remains the same, as does one of the down quarks. That’s a bit of a surprise, because gluons didn’t feature in the original quark model. Scattering Experiments at SLAC in the 1960s suggested that pointlike particles exist in the proton Atom Proton dddd uuuu uuuu + + + + +--- --Pre-Experiment Post-Experiment. Color Quarks possess a property to which has been given the name color. A proton has a mass of approximately 938 MeV/c 2, of which the rest mass of its three valence quarks contributes only about 9.4 MeV/c 2; much of the remainder can be attributed to the gluons' QCBE. The quark content of the proton is studied using the quark scalar bilinear, q q, as a probe. So, how much of the proton … For example: Meson quark composition charge/e pion Notice that in all cases, the charges of the particles add to a whole number multiple of the electron charge e, or 0. Six quarks and six anti-quarks have been discovered. Quark Model Hadrons Isospin, Strangeness Quark Model 3 Flavours u, d, s Mesons Pseudoscalar and vector mesons Baryons Decuplet, octet Hadron Masses Spin-spin coupling Heavy Quarks Charm, bottom, Heavy quark Mesons Top quark Motivation for Quark Model Particle “Zoo” proliferates “ … the finder of a new particle used to be rewarded This model fits decay results. The interpretation of the quark content is discussed in both models. In 1974 a meson called the J/Psi particle was discovered by experimenters at Stanford (Richter) and Brookhaven National Laboratory (Ting). We review the quark-meson coupling model, in which the quark degrees of freedom are explicitly involved to describe the properties of not only nuclear matter but also finite nuclei. Then, we present the electric and magnetic form factors for the proton bound in specific orbits for several closed-shell nuclei. The proton is likely a composite particle of four quarks and one anti-quark called a pentaquark, as evidenced by higher energy experiments found at CERN in 2015. Baryons consist of 3 quarks. A red up quark with spin down A green up quark with spin up . Furthermore, quarks are likely electrons and anti-quarks are positrons as pictured below. A blue down quark with spin up . Proton The Quark Model and SU(3) Peyton Rose 10 June 2013 Physics 251. The Proton in the Quark Model Click on the image to select a quark The Neutron in the Quark Model The Atom Back to table of contents. An additional quantum number – Quark mass. For example: Baryon quark composition charge/e neutron udd proton uud Mesons consist of quark-antiquark pairs. It is a secondary reaction in which an accelerator-produced K − collides with a proton via the strong force and conserves strangeness to produce the Ω − with characteristics predicted by the quark model. As with other predictions of previously unobserved particles, this gave a tremendous boost to quark theory. An analysis of hadron masses and the sigma term suggests an unexpectedly large signal for s s. This is seen to be reasonable within both the Skyrme model and the bag model. The gluons come first. The constituent quark model wavefunction for the proton is The strong interaction is one of the fundamental forces of nature, which binds quarks into hadrons such as the proton and the neutron, the building blocks of atoms. With a mass of 3100 MeV, over three times that of the proton, this particle was the first example of another quark, called the charm quark.The J/Psi is made up of a charm-anticharm quark pair. The Charm Quark. J. Brau Physics 661, The Quark Model 1 The Quark Mode l • Isospin Symmetry • Quark model and eightfold way • Baryon decuplet • Baryon octet • Quark spin and color • Baryon magnetic moments • Pseudoscalar mesons • Vector mesons • Other tests of the quark model