High Energy Physics: Messenger Particles

The next stop on our particle journey--- messenger particles.

The four forces or interactions we previously mentioned are mediated by particles that act like messengers, hence the name, "messenger" particles. These particles serve as messengers between such particles like leptons and quarks, enabling them to interact. Letís take a closer look at each one:

1. Gravitational interaction-

The hypothetical gravitational quantum or particle , the graviton, is the messenger particle for gravity.

2. Weak interaction-

The messenger particles for the weak force are W-plus, W-minus, and Z-zero.

The "plus" refers to the Wís charge, which is positive. The "minus" means a negative charge, and the "zero" for the Z particle is zero or neutral charge.

3. Electromagnetic interaction-

The photon is the messenger particle for the electromagnetic force.

4. Strong interaction-

Gluons serve as messengers for the strong force. They bind (glue) the quarks together. You never see quarks or gluons by themselves. They are always found bound together with other quarks and gluons. Hereís why:

Quarks have charges called "color" charges that come in three types- red, green and blue. These colors are just labels and have nothing to do with what the quarks would look like. The strong quark- binding gluons have the color charge themselves and stick to the color charges on other particles. In this way the strong force is mediated by the colored gluons and are suppose to be so strong that all quanta which possess a color charge.are permanently bound together. Therefore, the quarks, since they have the color charge, are permanently bound to each other by the gluons. Even the color gluons, because they have the color charge, also stick to themselves so tightly that they never become unglued.

Particles, like the proton, that are made of quarks (this class of particles is called "hadrons") must have one of each color of quark so that the total color of the object is a natural white. This is in analogy to combining red, green, and blue lights to get white light.

For every particle there is an anti-particle. In the next stop on our tour we will discuss antimatter.

Click here to go to the antimatter page.

Click here find out about the Higgs particle.

Click here to explore the different kinds of quarks and leptons.

Click here to discover the role of symmetry in nature.

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Text by Chandra Graves

Last Updated: November 9, 2009

baringer@ku.edu