A Six-Quark Dressed-Bag Description of np→dγ Radiative Capture

Abstract

The radiative capture process np → dγ is considered within the framework of a recently developed six-quark dressed-bag model for the nucleon-nucleon interaction. The calculations presented here include both the nucleon current and the meson-exchange current contributions. The latter uses short-range hadronic form factors for the pion exchange currents consistent with the soft cut-off parameter Λ πN N from the N N -potential. Contributions of the pion exchange current and ∆-isobar current to the total cross section still cannot explain the discrepancy between the theoretical and experimental cross sections. Possibilities for new types of meson exchange currents associated with chiral fields inside multi-quark dressed-bag states in nuclei are discussed.

Isoscalar short-range current in the deuteron induced by an intermediate dibaryon

“…in the deuteron deduced within many phenomenological models. Table I gives the summary of the static characteristics of the deuteron found with this dibaryon model [23,51].…”

“…(48) is calculated with Eqs. (49) -(50) and we employ the fixed values (19) and (51) and Z = 1 in Eq. (24).…”

Description of intermediate- and short-range NN nuclear force within a covariant effective field theory

“…And these production processes through the intermediate dressed dibaryon should have much a higher probability than the corresponding processes by absorption on one nucleon or on a meson-exchange current. Our first calculations made within the framework of this approach to treat some electromagnetic processes in 2N and 3N systems have lead to quite promising results [36,37,40].…”

Correlated two-pion exchange and large-Ncbehavior of nuclear forces

“…( 54) so accurately represents the short-distance part of the CrTPE force. At the same time, it is very difficult to argue that the scaling of scalar-isoscalar nuclear forces, first predicted by Kaplan and Manohar [38], and the observation which we made here, are not accidental, because it is very difficult to justify any phenomenological models at such separation scales where the baryon number is not well defined [3,67] and where other hard QCD processes [68] should play some role. We also recall that the χQSM itself as provided by the action Eq.…”