Baryons: Do the Quarks Add Up?

       
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Baryons are hadrons consisting of 3 quarks each. There are a variety of baryons; each has a charge of +1, -1, or 0. The most commonly observed baryons are made up of the very lightest quarks or their antiquarks. The table below will help you to become familiar with the different types of quark.
Quark Flavor Mass (GeV) Electric Charge
up (u) 0.003 2/3
down (d) 0.006 -1/3
charm (c) 1.3 2/3
strange (s) 0.1 -1/3
top (t) 175 2/3
bottom (b) 4.3 -1/3


Can you figure out, based on their charges and the fact that they are commonly observed in nature, what the quark structures of the proton, the neutron and the antiproton are?

Can you find the masses of these three common baryons by adding up the masses of their quarks? Try it!

The Baryon Table has answers and more data to analyze.

Now that you have examined and analyzed the data, consider these questions. . ..

  1. How, if at all, does the sum of the quark masses in a baryon indicate what the baryon mass will be?

  2. Is there some sort of proportionality between net quark mass mq and baryon mass Mb?

  3. Can you write an empirical mathematical equation relating net quark mass mq and baryon mass Mb?

  4. What is the significance of the relationship you found between mq and Mb?

  5. How do you explain this relationship in terms of the physics involved in binding three quarks together to make a baryon?