K

The two-particle momentum correlation function of a K^{-}p pair from high-energy nuclear collisions is evaluated in the K[over ¯]N-πΣ-πΛ coupled-channel framework. The effects of all coupled channels together with the Coulomb potential and the threshold energy difference between K^{-}p and K[over ¯]^{0}n are treated completely for the first time. Realistic potentials based on the chiral SU(3) dynamics are used which fit the available scattering data. The recently measured correlation function is found to be well reproduced by allowing variations of the source size and the relative weight of the source function of πΣ with respect to that of K[over ¯]N. The predicted K^{-}p correlation function from larger systems indicates that the investigation of its source size dependence is useful in providing further constraints in the study of the K[over ¯]N interaction.

Structure of near-threshold s-wave resonances.

We study the structure of two-body s-wave bound states as well as resonances in the threshold energy region. We focus on the single-channel scattering where the scattering length and the effective range are given by real numbers. It is shown that, in the energy region where the effective range expansion is valid, the properties of resonances are constrained only by the position of the pole. We find that the compositeness defined through the analytic continuation of the field renormalization constant is purely imaginary and normalized for resonances. We discuss the interpretation of this quantity by examining the structure of the hadron resonance Λc(2595) in the πΣc scattering. We show that the Λc(2595) resonance requires an unnaturally large effective range and hence it is not likely a πΣc molecule.

Identifying multiquark hadrons from heavy ion collisions.

Identifying hadronic molecular states and/or hadrons with multiquark components either with or without exotic quantum numbers is a long-standing challenge in hadronic physics. We suggest that studying the production of these hadrons in relativistic heavy ion collisions offers a promising resolution to this problem as yields of exotic hadrons are expected to be strongly affected by their structures. Using the coalescence model for hadron production, we find that, compared to the case of a nonexotic hadron with normal quark numbers, the yield of an exotic hadron is typically an order of magnitude smaller when it is a compact multiquark state and a factor of 2 or more larger when it is a loosely bound hadronic molecule. We further find that some of the newly proposed heavy exotic states could be produced and realistically measured in these experiments.

Exotic hadrons in s-wave chiral dynamics.

We study s-wave scattering of a hadron and a Nambu-Goldstone boson induced by the model-independent low energy interaction in the flavor SU(3) symmetric limit. Establishing the general structure of the interaction based on group theoretical arguments, we find that the interaction in the exotic channels are in most cases repulsive, and that for possible attractive channels the coupling strengths are weak and uniquely given independent of channel. Solving the scattering problem, we show that the attraction in the exotic channels is not strong enough to generate a bound state.