GAUGE-FIELDS, HIDDEN LOCAL SYMMETRIES, AND MESON-EXCHANGE CURRENTS

The model dependence of the electromagnetic isovector meson exchange c urrent (MEC) operator at higher momentums transfer is studied. For thi s purpose, the MEC operator constructed from a Lagrangian of the pi rh o alpha(1) system obtained within the framework of the hidden local sy mmetries (HLS) approach is compared with the analogous operator derive d earlier from a minimal Yang-Mills (YM) Lagrangian. Numerical results for the deuteron disintegration near threshold show that the model de pendent part of the exchange current modifies the tail of the cross se ction sensibly and that the presence of the al meson both in the MEC a nd in the nuclear interaction provides a consistent description of the cross sections up to the momentums transfer t similar to 1.5 GeV2. It is also found that the standard pi + rho MEC does not possess the cor rect chiral properties. (C) 1997 Elsevier Science B.V.