NEW DATA ON DELTA(-BARYON PRODUCTION IN (P)OVER-BAR-D ANNIHILATION ATREST(+))

New experimental results on (p) over bar d annihilation at rest into p ions plus a high momentum proton in the final state are discussed. The data sample was collected using the OBELIX spectrometer at the LEAR f acility (CERN). The annihilation probabilities, or more precisely the yields (Y) via channels (p) over bar d --> 2 pi(-)pi(+)pi(0)p and (p) over bar d --> 3 pi(-)2 pi(+)pi(0)p with proton momenta p > 400 MeV/c have been measured for the first time: Y = (93.2 +/- 1.6) x 10(-4) and Y = (52.2 +/- 1.4) x 10(-4), respectively. The signal in the invarian t mass distribution of the p pi(+) system in the region of the well-kn own Delta(++) (1232)-isobar is clearly seen in reactions (p) over bar d --> 2 pi(-)pi(+)p, (p) over bar d --> 2 pi(-)pi(+)pi(0)p, (p) over b ar d --> 3 pi(-)2 pi(+)p and (p) over bar d --> 3 pi(-)2 pi(+)pi(0)p. The upper limit on reaction (p) over bar (Delta(-)Delta(++)) --> 2 pi( -)pi(+)p in the p (d) over bar annihilation at rest, which could be in terpreted as a manifestation of the Delta Delta component of the deute ron, was found to be Y less than or equal to 6.5 x 10(-5) with a 90% c onfidence level. (C) 1997 Published by Elsevier Science B.V.