Heavy particle content in QCD jets

We present the result of a calculation of the leading non-perturbative correction to the number of heavy quark-antiquark pairs in a gluon jet. This correction is [<αF2>α(M)/(N2-1)M4](-1/30Csub(F)+53/3780Csub(A)), where M is the mass of the heavy quark. N is the number of colors and Csub(F) and Csub(A) are the values of the Casimir operator in the fundamental and adjoint representations respectively. α(M) is the running coupling at the scale of the heavy quark and is the gluon condensate, usually determined to be <α/πF2>proportional0.012 GeV4. The non-perturbative correction is extremely small. (orig.)