Aspects of meson spectroscopy with bar NN annihilation

We focus on the potentialities of nucleon-antinucleon (bar NN) annihilation as a means of producing new mesonic states. The case for the existence of quasinuclear bar NN bound states is discussed in detail. Strong evidence for a 2++(0+) state of this type has been obtained at LEAR in annihilation from the p-wave (L = 1) bar NN system, in support of earlier sightings of this object in L = 0 annihilation at Brookhaven. In the next generation of LEAR experiments, the emphasis shifts to the search for mesons containing dynamical excitations of the gluonic field, namely glueballs and hybrids (Q bar Qg). We discuss some features of the masses, decay branching ratios and production mechanisms for these states, and suggest particular bar NN annihilation channels which are optimal for their discovery. 59 refs., 15 figs