Enhancement of the Higgs pair production at the CERN LHC: The minimal supersymmetric standard model and extra dimension effects

Neutral Higgs pair production at the CERN LHC is studied in the MSSM, the large extra dimensional (ADD) model and the Randall-Sundrum (RS) model, where the total cross section can be significantly enhanced compared to that in the SM. The $p_T,$ invariant mass and rapidity distributions of each model have been shown to be distinctive: The ADD model raises the $p_T$ and invariant mass distributions at high scales of $p_T$ and invariant mass; in the RS model, resonant peaks appear after the SM contribution dies away; the SM and the MSSM distributions drop rapidly at those high scales; in the ADD and the RS models, the rapidity distributions concentrate more around the center. We conclude that various distributions of Higgs pair production at the LHC with restrictive kinematic cuts would provide one of the most robust signals for the extra dimensional effects.