Nonperturbative corrections to moments of the decay B -> X_s l^+ l^-

We study nonperturbative corrections to the inclusive rare decay B -> X_s l^+ l^- by performing an operator product expansion (OPE) to O(1/m_b^3). The values of the matrix elements entering at this order are unknown and introduce uncertainties into physical quantities. We study uncertainties introduced into the partially integrated rate, moments of the hadronic spectrum, as well as the forward-backward asymmetry. We find that for large dilepton invariant mass q^2 > M_{\psi'}^2 these uncertainties are large. We also assess the possibility of extracting the HQET parameters \lambda_1 and \bar{\Lambda} using data from this process.Comment: 24 pages, revtex, 4 figures, added an appendix with details, results unchange