Baryons from supergravity

We study the construction of baryons via supergravity along the line suggested recently by Witten and by Gross and Ooguri. We calculate the energy of the baryon as a function of its size. As expected the energy is linear with N. For the non-supersymmetric theories (in three and four dimensions) we find a linear relation which is an indication of confinement. For the N = 4 theory we obtain the result (E L= - const.) which is compatible with conformal invariance. Surprisingly, our calculation suggests that there is a bound state of k quarks if N/geq k/geq 5N/8. We study the N = 4 theory also at finite temperature and find the zero temperature behavior for small size of the baryon, and screening behaviour for baryon, whose size is large compared to the thermal wavelength. (author)