Reconstruction of smeared spectral functions from Euclidean correlation functions

We propose a method to reconstruct smeared spectral functions from two-point correlation functions measured on the Euclidean lattice. An arbitrary smearing function can be considered as long as it is smooth enough to allow an approximation using Chebyshev polynomials. We test the method with numerical lattice data of charmonium correlators. The method provides a frame-work to compare lattice calculation with experimental data including excited-state contributions without assuming quark-hadron duality.