Pionic decay of a possible d′ dibaryon

Abstract

The pionic decay of a possible d ′ -dibaryon in the process d ′ → N + N + π is studied in the microscopic quark shell model and with a single-quark transition operator describing the transition q → q + π. For the d ′ with quantum numbers J P = 0 − , T = 0, we employ a six-quark shell-model wave function with a spatial s 5 p[51] X -configuration and with N = 1 harmonic oscillator quanta. It is shown that the pionic decay width depends strongly on the mass and size of the d ′ . In the case that the calculated d ′ mass is close to the experimental one a small pionic decay width of Γ π ≈ 0.04 MeV is obtained. This is an order of magnitude smaller than the experimental Γ exp π ≃ 0.5 MeV. Two possibilities to improve the calculated width are suggested. The effect of the nonstatic correction term in the transition operator and the influence of the form factor at the decay vertex on the decay width are also discussed.

d′dibaryon in a colored cluster model

“…An important test of the d ′ hypothesis is the simultaneous description of the mass and the free pionic decay width Γ d ′ ≃ 0.5MeV of the d ′ with the same set of parameters. Model III gives a free d ′ decay width of Γ d ′ ≈ 0.3 MeV, which is in agreement with experimental result [28]. In the future, a detailed analysis of the Nd ′ and d ′ d ′ interactions similar to the calculation of the NH [56] and HH [57] interactions, as well as a calculation of the cross section for d ′ N → NNN should be done.…”

“…The model used here accurately reproduces the mass of the deuteron, which is the only established dibaryon. By comparing the RGM solutions with our previous results [26][27][28], employing a single s 5 p 1 six-quark "bag", we can test the validity of the assumption underlying the stringlike bag model, namely that the d ′ is a stretched q 2 − q 4 system. In the present work, all complications arising from the quark exchange interactions (Pauli principle) are rigorously taken into account, and their effect on the d ′ mass and wave function is investigated in some detail.…”

Understanding the structure of d*(2380) in chiral quark model

“…One sees that the CC component dominates the structure of the d * , as the fraction of the CC channel in d * is about 66%−68%. Note that according to symmetry, a pure hexaquark state of the ∆∆-CC system with isospin I = 0 and spin S = 3 reads [6] orb [33] [31] will be present in the next section, where we will see that apart from the mass, the picture we proposed here for d * also results in a good agreement of the decay width compared with the data reported by WASA-at-COSY Collaboration.…”

“…Following Refs. [33,34], the Hamiltonian density for the quark-quark-pion interaction in non-relativistic approximation reads…”

A (p/E) calculation of strong pionic decays of baryons

“…Furthermore an extended pion-quark vertex could be considered through a form factor multiplying f qqπ (or γ). An estimation of its importance for a standard dipole type form factor [12] gives corrections to the widths of a 20 % at most. It is also worthwhile to realize the better predictions on the average that threequark potential provide.…”