Higgsonium in singlet extension of Standard Model
  A possible formation of bound state is predicted in the Standard Model extension with with additional scalar singlet. A suitable method of solution of the Bethe-Salpeter equation for a Higgsonium bound state is proposed. With the help of an integral representation the results are directly obtained in Minkowski space. The appearance of Higgsonia is shown to be quite natural for considered extension of Standard model and the calculations are presented for the bound state composed from two scalars which result from the large mixture of electroweak doublet and singlet eigenstate. 
Vladimir Sauli