  We discuss the search for the heavy charged Higgs bosons H^\pm, implicitly of
the Minimal Supersymmetric Standard Model, in the tau-nu decay mode at the LHC.
Compared to the dominant decay mode H^\pm\to bt, the channel suffers from
suppression due to the branching ratio and the lack of direct mass
reconstruction, but the reduced QCD background makes it a feasible channel
especially in the large tan(beta) region. We study the production in `bt
fusion' via bg\to tH^-, and the leading irreducible background bg\to tW^-. Our
results indicate that for the H^\pm mass of greater than 200 GeV and up to 1
TeV and higher, they can be discovered in this channel for a vast range of the
parameter space, down to at least tan(beta)\sim3 and potentially the whole
range of tan(beta) down to 1.5 if the signal selection efficiency can be
improved fourfold. Our analysis is sensitive to top quark identification at
large rapidity, and should be supplemented with a full study including jet
showering and detector effects.
