Tetraquarks composed of 4 heavy quarks
  In the current work spectroscopy and possibility of observation at the LHC of tetraquarks composed of 4 heavy quarks is discussed. Tetraquarks concerned are T_{4c}=[cc][cc]$, T_{4b}=[bb][bb] and T_{2[bc]}=[bc][bc]. By solving nonrelativistic Schroedinger equation masses of these states are found with the hyperfine splitting accounted for. It is shown that masses of tensor tetraquarks T_{4c}(2++) and T_{2[bc]}(2++) are high enough to observe these states as peaks in the invariant mass distributions of heavy quarkonia pairs in pp -> T_{4c}+X -> 2J/\psi+X, pp -> T_{2[bc]}+X -> 2B_{c}+X and pp -> T_{2[bc]}+X -> J/\psi\Upsilon(1S)+X channels while T_{4b} is under the threshold of decay into a vector bottomonia pair. 
A. V. Berezhnoy, A. V. Luchinsky, A. A. Novoselov
hep-ph