摘要
In the general Higgs portal-like models, the extra neutral scalar, S, can mix with the Standard Model (SM) Higgs boson, H. We perform an exploratory study focusing on the direct search for such a light singlet S at the Large Hadron Collider (LHC). After careful study of the SM background, we find the process pp→ttS followed by S→bb can be used to investigate S with mass in the 20<MS<100 GeV range, which has not been well explored at the LHC. The signal significance becomes meaningful with a luminosity around a few ab-1. Also, we study the prospects of finding the light scalar at the future 100 TeV pp collider, the Z and Higgs factories. With similar luminosity, the current Large Electron-Positron Collider (LEP) limits on the mixing between S and H can be improved by at least one or two order of magnitudes.