Activation Gaps and Mass Enhancement of Composite Fermions

We compute the activation gaps for fractional quantum Hall states at filling fractions $\nu =n/(2n+1)$ incorporating modifications in the interaction potential due to the nonzero transverse width of the electron wave function and find good agreement with experiments in high-mobility samples with high density. The results also shed light on the mysterious enhancement of the composite fermion mass for fractions with large $n$.