Particles, Gluons And Atoms

Shape

Since we know that gluons attract each other when moving between two quarks we can imagine how gluons behave between three quarks in a baryon like that in a proton or neutron. If you can imagine it, the three gluon flux tubes that form a triangular shape with the vertices being the position of the quarks, bend towards the center of the hadron due to them attracting one another. This forms a Y shaped structure.

Credit to Research Gate

^on the left is a picture of a meson and on the right is what baryon (neutron, proton)

Mass And Spin

Most of the mass and spin of any hadron does not come from the valence quarks, which are quarks that do not change within the hadron, but rather the gluons going between the valence quarks. As a result of the fact that the gluon field is fluctuating, gluons can form virtual, anti particle particle pairs when the distance between two quarks is great enough. These quarks are known as sea quarks.  Sea quarks are what gives hadrons most of their mass. In other words, the strong nuclear force is what gives hadrons most of their mass. In the previous article we showed that gluons can split into more gluons, this can explain the resulting spin of the proton.

* The diagram on the right is a simplified sketch of how the inside of proton might look like. The model above is known as the sea quark model, there is also a meson cloud model where particles and anti- particles from different gluons form mesons and meson pairs which cover the outskirts of the proton or neutron. Both these models are being used to resolve the spin and mass conundrum of protons and neutrons.

Residual Strong Nuclear Force

Turns out gluons are the driver for keeping protons and neutrons together in the atom. The distance at which these interactions occur is about 1 fermi. There are a variety of interactions that explain residual strong force interactions, but the ones I've researched all involved an energetic gluon resulting in the emission and absorption of a meson. Think of mesons like a shared electron between two hydrogen atoms. Mesons decay relatively quickly and are basically a single color, anti-color pair (because net color charge is white). The picture below are rough sketches by me which show how these interactions work:

            Note that in the first diagram the excited gluon becomes a down quark and anti-down quark which kick starts the interaction.

Electrons

Electrons in accordance to QFT are nothing but excited standing waves which stay in their relative energy levels around the nucleus. We don't know exactly how exactly an electron moves around the nucleus. That being said the first picture below demonstrates the probability at which you can find the electron in each orbital. To explain discrete energy levels we can imagine an electron moving in wave like motion around the nucleus of an atom. Variable n is the number of nodes in the wave and represents the energy level. Notice how the number of nodes is always an integer, which explains he discrete aspect of energy levels as n can never be a fraction. Also note that the larger n is, the larger the energy level, vice versa.

Scalar Boson: The Higgs

The Higgs boson, is a temporary excitation in the Higgs field, and mediates the interaction between the Higgs field and fundamental particles, it also has a spin of 0 and no electric charge. The Higgs boson doesn't generate mass, but fundamental particles get their mass by interacting the with virtual Higgs bosons which form and decay in the field. The more other elementary particles interact with this field, the more mass the particle has. This interaction of course occurs by attracting these Higgs virtual particles. Photons and gluons do not interact with the Higgs field in any way, thus they have no mass and don't attract any Higgs virtual particles. Keep in mind that the Higgs field unlike other fields is elevated through out space.

The picture above is what the Higgs field looks like. At the crest of this field the Higgs field has no strength and at the trough, the field has some strength and the potential is 0. Its almost impossible to stay at the crest of this field because of the fact that vacuum isn't empty. Thus the symmetry breaks and all massless particles lie at the bottom of the trough. The Higgs boson is formed when a massless particle oscillates about the crest and trough area of the field, which requires quiet a bit of energy. Particles moving around the circular trough is known as the Goldstone boson and unlike the Higgs, it requires no energy and experiences no change in potential and as a result it is massless.

Interestingly enough the Higgs boson can interact with its own field allowing to have mass, and can be detected. Though the particle is still some what theoretical, CERN's LHC discovered a particle that aligned well with the Higgs Boson's properties in 2012.

Feynman Diagrams: Gauge Bosons

As I've mentioned multiple times: Gauge Bosons are force carriers and all of them have a spin of 1. Note that these bosons transfer momentum, energy and spin. Thus if you look at a Feynman diagram the interacting particles tend to change direction of particles post interaction because they can transfer momentum.

Virtual particles last for very short periods of time They are similar to regular particles in the fact that they are "clumps" in their respective field, the difference being that the energy level of these clumps are lower than that of regular particles. Virtual particles temporarily borrow energy from quantum fluctuations and then like the customer of a bank, pay the bank back by transferring the energy in order to become stable. Virtual particles include vector* bosons, scalar bosons and mesons. Vector bosons also include known Gauge Bosons such as W, Z bosons, gluons, and photons while scalar bosons include the Higgs Boson.

 Photons are gauge bosons that moderate the interaction between charged particles and the electromagnetic field. Its part of the electromagnetic field because it has a magnetic field component. Repulsion and attraction between charged particles is mediated by virtual photons. If this doesn't make sense think about the photo-electric effect where photons result in electron emissions. The virtual photons "disappear" by transferring their energy and momentum to the charged particles in opposite directions to create a perceived repulsion or attraction. 

W and Z bosons are part of the electroweak field. W Bosons can be + or -  charged, and are the primary driver of beta decay and carriers of the weak force and transfers charge. The weak force is the force that governs interactions between leptons and hadrons; often occur at very small distances.  Beta decay is process that occurs because of the weak force and is a result of too many protons or neutrons in the nucleus of an atom.  But you see the entire proton or neutron isn't changing, only a single quark is changing. The W+ boson being separating from the up quark means that the up quark becomes less positive and thus becomes a down quark. We can also see how the W bosons instability causes it to decay into stable fermions.

 

E= planks constant/(change in time): the more energy the boson borrows, the lesser the time the boson will live.

Another Weak force boson is Z boson which is neutrally charged. When annihilation of the W- and W+ boson occurs, a Z boson can be produced. Z bosons are the mediators of neutral current; a subset of the weak force where the boson doesn't transfer charge or change the quantum numbers of the interacting particles, unlike the W bosons. It's used to explain interactions involving particles with no charge such as neutrinos that can only interact with each other and other particles at small distances (ex. : electrons and electron neutrino "repulsion")

* w/direction