  The single top production proceeds through different channels at LHC. The
t-channel production which has a cross section at the level of one third of the
ttbar, can be regarded as a source of light charged Higgs boson through top
quark decay to charged Higgs. Due to the low jet multiplicity and
characteristic kinematic features of this process, a signal selection can be
designed to extract charged Higgs signal from the background processes. In this
paper, taking MSSM as the theoretical framework, The light charged Higgs signal
from single top events is analyzed. The charged Higgs is assumed to decay to
tau nu and the hadronic decay of tau leptons is analyzed. Different charged
Higgs mass hypotheses are analyzed and a scan over the parameter space
(mH+,tanbeta) is performed. It is shown that this process has the potential to
exclude large areas of parameter space, while with enough data, a 5 sigma
discovery would also be possible. Finally 95% C.L. exclusion and 5 sigma
contours are provided for different integrated luminosities of LHC.
