  Renormalization group analysis of boundary conformal field theory on bosonic
D25-brane is used to study tachyon condensation. Placing the lump on a finite
circle and triggering only the first three tachyon modes, the theory flows to
nearby IR fixed point representing lumps that are extended object with definite
profile. The boundary entropy corresponding to the D24-brane tension is
calculated in the leading order in perturbative analysis which decreases under
RG flow and agrees with the expected result to an accuracy of 8%. Multicritical
behaviour of the IR theory suggests that the end point of the flow represents a
configuration of two D24-branes. Analogy with Kondo physics is discussed.
