## The Standard Model

Here we're briefly described the particles that make up the current standard modelof physics. According to a classic thoerem of group theory by Wigner, particles can be completely classified by there spin (angular momentum, much like a spinning top except that elementary particles are pointlike), and there mass. Another theorem of quantum mechanics called the pauli principle, quickly divides the particles into Fermions with spin 1/2 and bosons with spin 0 or 1. Fermions because of their spin are conserved in number, the cannot appear and disappear, except by pair production of annilhilations with there corresponding anti-fermion. Fermions also obey the law (Pauli's principle), that they can never overlap with another identical fermion. Thus Fermions our the particles that make up matter, they have the capacity from solid material for instance. In the standard model all spin-1 bosons represent the force between fermions, and are in fact added to the theory in order to the make the maths of transformations between fermions, obey the same laws everywhere and everywhen, a principle known as gauge symmetry..

### The Bosons, or force carrying particles

The standard model has just 3 forces (it can't deal with gravity yet), caused by, 1 photon (the quanta of light and the electromagnetic force), 8 gluons which swap the colors of the quarks and cause the strong nuclear force. A pair of W particles, one positive one negative, which cause the weak nuclear decays, by transforming one type of quark to another or one type of lepton to another. And finally a Z particle which is like a slightly heavy neutral W particle, but which doesn't transform the particles it interacts with.

Apart from these are unknown number of so far undetected Higgs particles which have 0-spin and are added to the model to give of other particles masses. We won't discuss the Higgs particles further here.

#### The Matter Particles or Fermions 1. - The Leptons

 Standard fermions have spin-1/2 are normally described, by the Dirac equation, which gives four different states for each particles, positive and negative spin, (clockwise or anticlockwise, but often called spin-up or spin-down) for a matter state, and positive and negative spin for an antimatter state. So for electron we get the following four states.

Electrons are sources of the electromagnetic field. We've drawn the field line in black, the incoming arrows represent the fact the electron has negative charge, while the outgoing arrows on the anti-electron or positron, (drawn in inverse colors), indicate a positive charge. We also drawn a spin axis (the metal pole), with all are particles travelling up the page, so that we can easierly see the difference between left-handed (anti-clockwise) and right-handed (clockwise) spin particles. The direction of spin is important as we see with the neutrino below. The neutrino is the one particle in the standard model that doesn't seem to be of Dirac type. We see that left handed neutrino and right handed antineutrino, but not the other too. How this can be is what my paper tries to address.

Together electrons and the neutrinos (and as we'll see there two heavier copies), make up the a group of particles called the Leptons, the weak force can transfom one to another but only if there both left handed matter types, or both right handed anti-matter types.

#### Matter Particles, Fermions. 2. The Quarks

Next we have the quarks, quarks come in one of three colours, (this property of quarks was named because it obeys the same combination law as colours of light, red plus green plus blue equals white or neurtal). Quarks come together under to colour force to form Hadrons such as the proton and neutron, obeying the law that only white particles are observed in nature. In each generation there is an up-type quark with electric charge +2/3 and a down type quark with electric charge -1/3. The names up and down have nothing to do with physical spin, but where named after a property that obeyed similar maths called isospin.The weak force is able to transform up and down type quarks, keeping the color the same, but only if the quark is left spinning or an anti-quark is right spinning

#### Three Generations of Matter Particles

If all that wasn't enough we have another two copies of above particles, each generation heavier than the last, (the neutrino masses unknown). The electrons, is partnered with the muon, and then the tau or tauon. The up quark with the charm and then the top quark, and the down quark with the strange and then the bottom quark. There is also one neutrino for each different kind of electrons. So in it total (ignoring colors, and spin, and antimater) we get a table like.

#### Why these states and no others? Grand Unified Theories

The above pattern of particles is confusing to physicists, we'd like to have a deeper explanation of why we see the above particles. Why 3 colors of quarks, but no colors of leptons, why three generations, why do only the left handed particles interact via the weak force. One thing that can be explained is the pattern of charges on the particles, we require each generations charges add up to zero, no matter the spin of matter/antimatter type of the particles. So -1 + (2/3+ -1/3)*3 = 0, fixes the charges on the particles and there aren't many other ways to arrange it.

#### For my own guess at a Grand Unified Theory click here

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