Hunting for exotic doubly hidden-charm/bottom tetraquark states

We develop a moment QCD sum rule method augmented by fundamental inequalities to study the existence of exotic doubly hidden-charm/bottom tetraquark states made of four heavy quarks. Using the compact diquark-antidiquark configuration, we calculate the mass spectra of these tetraquark states. There are 18 hidden-charm cc (c) over bar(c) over bar ctetraquark currents with J(PC) = 0(++), 0(-+), 0(--), 1(++), 1(+-), 1(-+), 1(--), and 2(++). We use them to perform QCD sum rule analyses, and the obtained masses are all higher than the spontaneous dissociation thresholds of two charmonium mesons, which are thus their dominant decay modes. The masses of the corresponding hidden-bottom bb (b) over bar(b) over bar tetraquarks are all below or very close to the thresholds of the (sic)(1S)(sic)(1S) and eta(b)(1S)eta(b)(1S), except one current of J(PC) = 0(++). Hence, we suggest to search for the doubly hidden-charm states in the J/psi J/psi and eta(c)(1S)eta(c)(1S) channels. (C) 2017 The Authors. Published by Elsevier B.V.