Yukawa coupling quantum corrections to the self-couplings of the lightest MSSM Higgs boson

A detailed analysis of the top-quark/squark quantum corrections to the lightest CP-even Higgs boson (h0) self-couplings is presented in the MSSM. By considering the leading one-loop Yukawa-coupling contributions of O (mt4), we discuss the decoupling behavior of these corrections when the top squarks are heavy compared to the electroweak scale. As shown analytically and numerically, the large corrections can almost completely be absorbed into the h0-boson mass. Our conclusion is that the h0 self-couplings remain similar to the coupling of the SM Higgs boson for the heavy top-squark sector. (orig.)