Antidecuplet candidateΞ--(1862)as a heptaquark with the overlap of two antikaons and a nucleon

Abstract

I study the very recently discovered S=-2 resonance Ξ −− (1886) by the NA49 collaboration at the CERN SPS. This resonance was already predicted, with a mass close to 1.9 GeV, in a recent publication mostly dedicated to the S=1 resonance Θ + (1540). To confirm this recent prediction, I apply the same standard quark model with a quark-antiquark annihilation constrained by chiral symmetry. This method also explained with success the repulsive hard core of nucleon-nucleon, kaon-nucleon exotic scattering, and the short range attraction present in pion-nucleon and pionpion non-exotic scattering. I find that repulsion excludes the Ξ −− as a ddssū s-wave pentaquark. I explore the Ξ −− as a heptaquark, equivalent to a N + K + K linear molecule, with positive parity and total isospin I = 3/2. I find that the kaon-kaon repulsion is cancelled by the attraction existing in the kaon-nucleon channels. In our framework this state is easier to bind than the Θ + described by a π + K + N borromean bound-state. The remaining I = 1/2 doublet and I = 1 triplet of the exotic anti-decuplet are also studied, and the coupling to p-wave decay channels is briefly addressed.

Prediction of the masses and decay processes of strange, charmed and bottomed pentaquarks from the linear-molecular crypto-heptaquark model

“…In very recent works, this principle was used to indicate that the + (1540) is probably a K •π •N molecule with a binding energy of 30 MeV [63][64][65] and the −− (1862) is a K •N • K molecule with a binding energy of 60 MeV [63,81]. I also suggest that the new positive parity scalar D s (2320) and axial D s+ (2460) are K • D and K • D * multiquarks [82], in agreement with the independent models of Barnes, Close and Lipkin and of Terasaki [83][84][85] and that the D * − p(3100) is consistent with a D * • π • N linear molecule with an energy of 15 MeV above threshold [63,86].…”