NAMBU-GOTO STRING WITHOUT TACHYONS BETWEEN A HEAVY AND A LIGHT-QUARK - REAL INTERQUARK POTENTIAL AT ALL DISTANCES

We point out that in infinite spacetime dimensions, the singularity in the interquark potential at small distances disappears if a Nambu-Got o string is anchored at one end to an infinitely heavy quark, at the o ther end to an infinitely light quark. This suggests that if such quar ks are placed at the ends, some unphysical features such as tachyon st ates are absent also in finite dimensions.