# Potential energy of quarks

I am to find the ratio of the gravitational PE to the Coulomb PE between a $$t$$ and a $$\bar{t}$$ quark

I dont know what a $$\bar{t}$$ quark is, but I am guessing that it is a quark that has a charge opposite of that of the $$t$$ quark?

I am given that the charges are $$+/- \frac{2}{3} e$$ and that the mass is 174 GeV/c^2.

I think this is how I should set this question up:

$$ratio=-\frac{GMm}{kQq}$$

$$ratio=-\frac{2G (174 GeV/c^2)}{k(\frac{2}{3} e) (-\frac{2}{3} e)}$$

is this correct?

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The ratio should not be negative. The rest of the solution, I think that you're right.

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why should the ratio not be negative? and what is a $$\bar{t}$$ quark?

Physics Monkey
Homework Helper
Usually the bar means its the antiparticle. In this case you have the top quark $$t$$ and the anti-top quark $$\bar{t}$$. The ratio of the two energies should be positive because both energies are negative.

Also, the gravitational potential energy is proportional to the product of the masses so you should have the mass squared rather than multiplied by two.

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oh right, so something like..

$$ratio=\frac{G (174 GeV/c^2)^2}{k(\frac{2}{3} e)^2}$$