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The mass of a singlet strangeness -2 state is calculated from a low-momenta QCD Lagrangian involving dynamically massive quarks interacting with pseudoscalar fields. Minimizing the aggregate energy of the quark Dirac sea plus the energy of a bound-state level of six valence quarks, we find MH =2. 11 GeV in the chiral limit. The mass shift due to the strange-quark mass is estimated to be of the order of 300 MeV. This state is classically parity degenerate. Its splitting and width are -N due to nonperturbative tunneling and therefore are suppressed as e Since 1977 when Jaffe showed that in a framework of the MIT bag model a six-quark state (uuddss, called H) has a mass as low as 2150 MeV (Ref. 1) there have been many calculations of the H mass in various models [bag model, ' lattice QCD (Refs. 4 and 5), quark-cluster model, and Skyrme model ' ] with predictions ranging from 1.56 GeV to more than 3 GeV. If MH (2MA then 0 would be stable with respect to strong interactions and could be seen in forthcoming experiments. " Therefore it is of considerable importance to have a reliable prediction for its mass.In this paper we calculate MH in a quark-soliton model' which proved to be successful in describing ordinary baryons. ' ' The model can be in a sense derived from "first principles" assuming that the QCD vacuum consists of instantons and anti-instantons forming a liquid phase. ' ' The instanton vacuum exhibits chiralsymmetry breaking, resulting in a momentum-dependent dynamical (constituent-)quark mass M (p) with M= -M(0)=345 MeV and massless pions. At this level pions act as a classical field, linearizing nonlocal, manyquark interactions.One can formally integrate out quarks; then the pion-field kinetic term arises from a fermion loop regularized in an appropriate way. [We freeze M(p) at its value at the origin and cutoff the divergent integrals to reproduce F and the quark condensate. ] The bound-state problem is then reduced to solving a Dirac equation, 1+@5~1 -y5 1p lk' +M U[p) +U [p] +m Bxk 2 2 in a trial pseudoscalar-meson field U[P] E SU(3), where a bare-quark mass matrix m =diag(m", md, m, ) has been included. This approach appears to be similar to that of large-Z atom allowing a semiclassical Thomas-Fermi treatment. One has to minimize an aggregate energy of N, quarks bound on each discrete level emerging from upper continuum plus the energy of the quark Dirac sea:

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