N. Konno

The analysis of the q2q2 system based on the diquark cluster model

Abstract Based on the diquark cluster model, the widths and branching ratios of the q 2 q 2 states, which consist of u and d quarks, as well as the mass spectrum are predicted. The mass spectrum is calculated using a mass formula in which all of the parameters are determined using known baryon masses and experimental data for dibaryon resonances: no free parameters remain. The widths and branching ratios are also estimated by the use of an approximated formula in which experimental data for the masses and widths of the meson q q are used and again no free parameters remain. It is shown that the present model can explain in a satisfactory fashion the masses and the widths of many exotic mesons discovered recently in s s - depleted reactions.

The Analysis of the Narrow Dibaryon Resonances Based on the Diquark Cluster Model

Since the finding of a narrow resonance by the measurement of the tensor polarization t 20 of πd elastic scattering in 1982 by ETH group[1], the search for the narrow dibaryon resonances has been continued.[2–4] Recently, Shimizu et al. measured the pp elastic analyzing power at KEK[5] and found a number of structures in the spectrum which may be caused by a group of narrow q 6 states with negative parity. Unfortunately, as well as ETH data, there is a contradictory data[6] against this KEK data and then the existence of narrow dibaryon resonance is still controversial.

Diquark cluster model and dibaryons

In this short article, we review the basic ideas, approaches and the major results of using the diquark cluster model in the analysis of dibaryon resonances.

The spin dependence of hadronic and leptonic production and scattering

In this short article, we discuss the problems of the spin structure of nucleons in high energy and high momentum transfer reactions from the viewpoint of the diquark cluster model. The model used was proposed in our earlier work for the purpose of analyzing the various properties of dibaryon resonances.

An examination of the longitudinal spin-dependent np total cross-section difference Δσl(I = 0) using diquark cluster model

SummaryThe resonating part of the ΔσL (I = 0) is calculated using the parameters which were extracted from pp elastic analyzing power data and compared with the structure in the ΔσL (I = 0) data. We discuss the mass spectrum of the dibaryons withI = 0 on the basis of the diquark cluster model.

An analysis of early data on heavy exotic mesons based on the diquark cluster model

SummaryEarly data with respect to heavy exotic mesons with narrow width (≤ 80MeV) found in π p reactions by Andersonet al. and Baudet al. in 1969–1970 are analyzed using the diquark cluster model. It is shown that the simple mass formula of the diquark cluster model, which involves no free parameters, can clearly reproduce the mass spectrum for the heavy exotic mesons indicated by the empirical data.

An examination of pp elastic analyzing power using the diquark cluster model

SummaryAn examination of pp elastic analyzing power is conducted using a semi-phenomenological approach based on the diquark cluster model. It is shown that the structures observed empirically can be closely reproduced using the present approach. The elastic pp differential cross-section at θc.m. = 90 ° is also calculated and compared with the experimental data.

The widths of the dibaryon with I=1 and JP−0−, 1−, 2−

The diquark cluster model predicts that some narrow dibaryon resonances with negative parity are degenerate at three energy levels of approximately 2.13, 2.19, and 2.25 GeV. This prediction may be quite consistent with the experimental analysis of the missing mass spectrum in the p+3He→d+X reaction studied by Tatischeff et al., in which they found three narrow peaks at 2.121, 2.192, and 2.240 GeV. In this short article, we report our predictions for the widths of these narrow resonances calculated using the diquark cluster model as well as their precise resonating energies.  (AIP)