The pentaquark is studied in a simple model of confinement where the quarks
and the antiquark are linked by flux tubes of minimal cumulated length, and the
Coulomb-like interaction, the spin-dependent terms and the antisymmetrization
constraints are neglected.. The ground-state is found to be stable against
spontaneous dissociation into a meson and a baryon, both in the case of five
equal-mass constituents and for a static quark or antiquark surrounded by four
equal masses.Comment: 8 pages, 2 figures, minor corrections, references added, to appear in
Phys. Rev.