THE EXISTENCE OF THE D$sup +$ MESON

The existence of the D/sup +/ meson, which should be an isotopic singlet (S = +2, T = 0), is allowed. This particle can decay by two paths: D/sup +/ yields K/sup +/+ + pi /sup 0/, and + D/sup +/ yields K/su p 0/ + pi /sup +/. The second path is twice as probable as the flrst path. The half life of the D/ sup +/ meson should be about 10/sup -10/ seconds (decay proceeds with a DELTA T = 1/2). The reaction K/sup +/ + p yields D/sup +/ + EPSILON /sup +/ was investigated in order to detect the D/sup +/ meson during its formation and decay in a propane bubble chamber. A beam of positive particles with a momentum of about 1.8 Bev/c, containing up to 9% K/sup +/ mesons was used to irradiate the propane bubble chamber. In all, 14,000 photographs were examined, but not a single case was found, where a D+ meson was formed. The upper limit for the formation cross section of a D/sup +/ meson by interaction of a K+ meson with a nucleon is estimated to be 1.2x 10/sup -29. cm/sup 2/. (TTT)