  We discuss the proposal of Hata and Kawano for the tachyon fluctuation around
a solution of vacuum string field theory representing a D25 brane. We give a
conformal field theory construction of their state -- a local insertion of a
tachyon vertex operator on the sliver surface state, and explain why the
on-shell momentum condition emerges correctly. We also show that a naive
computation of the D25-brane tension using data for the three point coupling of
this state gives an answer that is $(\pi^2/3)(16/27\ln 2)^3 \simeq 2.0558$
times the expected answer. We demonstrate that this problem arises because the
HK state does not satisfy the equations of motion in a strong sense required
for the computation of D-brane tension from the on-shell 3-tachyon coupling.

High Energy Physics - Theory