Homework due on 9/8 –> May the Force Be With You

The fundamental forces in Physics are Gravity, Weak, Electromagnetic, and Strong.  These forces are communicated among particles in many different ways, but specifically through the use of Force Carrier Particles.  The Force Carrier Particles are different for every interaction, but they all have the same goal of sparking interactions between matter particles.  For the Electromagnetic Force, which causes similarly charged particles to repel each other, and oppositely charged particles to attract each other, photons are the carrier particle.  Photons, which have zero mass and travel at the speed of light, cause charged parts of one atom to interact with charged parts of another, usually binding the different atoms together.  The next force is the Strong force, which is responsible for holding together the nucleus while the electromagnetic force is working to pull it apart.  The strong force does this using Gluons, to hold together quarks to form hadrons.  Gluons, along with quarks, carry a color charge.  When two quarks are close, they will exchange Gluons which creates a strong “Color Force Field” that binds the quarks together.  As the quarks get further apart, the force gets stronger, working to hold the quarks together, until ultimately they snap to create two new hadrons.  When a quark absorbs or emits a gluon, it changes color to conserve the color charge.  However, the process happens too quickly and often to observe the color change in an individual quark.  The interesting thing with this exchange, is that the environment of the hadron remains neutral while two quarks are exchanging a gluon.  The next force (or more correctly interaction) is that of “Weak”.  Weak interactions are responsible for the decay of big leptons and quarks into less massive quarks and leptons.  The carrier particles for weak interactions are W^+, W^-, and Z.  The process of Weak interaction decay is actually very interesting.  When a quark or lepton is being decayed into a smaller quark or lepton, the particle vanishes and then appears as two or more less massive particles.  The total mass and energy is conserved, but some of the mass is converted into Kinetic Energy.  In Physics, the Electromagnetic Force and Weak Interaction has been combined into one theory: the Electroweak.  This is because the two have a similar amount of strength, but the particles have vastly different masses, so the difference is observed because of the size inequality.  The last force is the most unknown in Physics: Gravity.  The Gravity carrier particle is a Graviton, however, no physicist has ever observed it.  It is predicted to exist, but has yet to be found.  However, even with this gap in our knowledge of the graviton, the effect of gravity on the particles is not significant enough to create an overwhelming feeling of dread amongst physicists and humans at our lack of evidence.  Physicists are capable of using theorized knowledge of Gravity instead of observed evidence in equations of particle physics.