Video Transcript
A type of omega baryon has the
composition ccc. What is the charm of this omega
baryon? What is the relative electric
charge of this omega baryon?
In this exercise, we’re working
with a particle made of exactly three quarks. And we’re told that each one of
those quarks is a charm quark. If we were to make a sketch of this
baryon then, it would look like this. For this composite particle, we
want to know what its charm and its relative electric charge are. Considering the first part of our
question, we know that the charm of a particle overall is determined by the number
of charm quarks and charm antiquarks it may possess. Every charm quark contributes a
charm, we could say, of positive one to the particle, while every charm antiquark
contributes a charm of negative one.
Looking at our omega baryon, we can
say then that this charm quark contributes a charm of positive one, so does this one
here, and so does the third one. The total charm for the omega
baryon will be the charm of each of these quarks combined, added together. One plus one plus one is three. So, that is the charm of this omega
baryon.
Now, let’s look at the second part
of our question, which asks about the relative electric charge of the particle. To figure this out, once again
we’ll use the properties of the charm quark. This quark, which we color in red
because it has a positive electric charge, has a relative electric charge of
positive two-thirds times e, where e is the charge of a single proton. Since each one of the charm quarks
in our particle has this same relative charge and note that here we’ve left off the
e as we sometimes do, then we can say that the omega baryon’s relative electric
charge equals the sum of these individual charges. Positive two-thirds plus two-thirds
plus two-thirds is six-thirds, or two. So, this is the relative electric
charge of this omega baryon.
