# String tension for quark anti-quark binding

1. Mar 14, 2013

### Chain

For quark anti-quark binding the potential takes the form:

$V(r) = -k/r + σr$

Where the first term comes from the Coulomb force and the second term comes from the strong nuclear force.

My question is whether $σ$ is the same for all quark anti-quark pairs or if it's different depending on which quark anti-quark pair is binding?

If so is there a way to calculate the string tension for a bottom anti-charm pair given $σ$ for the bottom anti-bottom and charm anti-charm mesons.

2. Mar 14, 2013

### The_Duck

$\sigma$ should be independent of the quark flavor. So should $k$ for that matter: the $-k/r$ term is actually also from the strong force, which has a Coulomb-like behavior at short distances (but with a different $k$ than the electromagnetic Coulomb force). In principle there is also an actual electromagnetic Coulomb term that depends on the electric charges of the two quarks, but this is negligible compared to the strong force.

3. Mar 15, 2013

### Chain

Ah okay thanks for clearing that up :)