THE PHASE OF COHERENT K(S) REGENERATION AND DISPERSION-RELATIONS

The phase of nuclear regeneration of K(S) mesons in a K(L) beam is rel ated to the momentum dependence of the regeneration amplitude (f(0) - fBAR(0))/k, via a dispersion relation. Using experimental data on the momentum dependence of the modulus of the amplitude, values for the re generation phase are derived for the regenerator materials copper, lea d, carbon and carborundum (B4C). The precision of these phases is abou t +/-3-degrees in the momentum region from 40 to 150 GeV/c. This uncer tainty limits the precision of measurements on the CP-violation phase phi+- in regenerator experiments.