Anomaly cancellation formulas and E_8 bundles for almost complex manifolds

In this paper, we extend the elliptic genus in [10] by the gauge group E_8 and the gauge group E_8*E_8. Then we prove that the generalized elliptic genus are the weak Jacobi forms. Using these elliptic genus, we obtain some SL_2(Z) modular forms and get some new anomaly cancellation formulas of characteristic forms for almost complex manifolds.