Invariant-mass distribution of cc̄ in Υ(1S)→cc̄+X

We calculate the invariant-mass distribution for the cc̄ pair produced in the inclusive Υ(1S) decay based on the color-singlet mechanism of the nonrelativistic quantum chromodynamics factorization approach at leading order in the bottom-quark velocity vb in the meson rest frame. As the short-distance processes, we consider bb̄→g*gg followed by g*→cc̄ and bb̄→γ*→cc̄ at leading order in the strong coupling. The invariant-mass distribution of the bb̄→cc̄gg contribution has a sharp peak just above the threshold and that of the bb̄→γ*→cc̄ channel is concentrated at the maximally allowed kinematic end point. We predict that Γ[Υ(1S)→cc̄+X]/Γ[Υ(1S)→light hadrons]=(0.065±0.048)αs, which is in agreement with a previous result within errors.