Light antinucleus yields are calculated in a multiphase transport model coupled with a dynamical coalescence model. The model is tuned to reproduce the transverse momentum and rapidity distributions of antiproton in pp collisions at √ s = 7.7 GeV to 7 TeV. By applying a widely used cosmic-ray propagation model, the antinucleus fluxes near the earth are estimated over a broad range of kinetic energies. Our result on the antideuteron flux is consistent with the calculations in the literature,

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... e our upper limit on the antihelium-3 flux sits in-between calculations in the field that span an order of magnitude in its value. This study suggests that further accurate estimation of secondary antihelium-3 flux could be improved with more ground-based experiments and model simulations. Most importantly, our value of antinucleus background from hadronic source is far below the projected sensitivity of AMS-02 with five years of integration time, which supports the idea of searching for new physics by measurements of light antinuclei in upcoming decade.