NEW ASTROPHYSICAL CONSTRAINTS ON THE MASS OF THE SUPERLIGHT GRAVITINO

In some supergravity models, the superlight gravitino is accompanied b y a light weakly coupled scalar (S) and pseudoscalar particle (P). The couplings of these particles to matter (e.g. electrons and photons) i s inversely proportional to the product (m(g)M(PI)) where m(g) and M-P I are respectively the gravitino mass and the Planck mass. as a result , their emission from supernovae and stars via the reaction gamma + e( -) --> S/P + e(-) for certain ranges of the gravitino mass can become the dominant energy loss mechanism in contradiction with observations thereby ruling out those mass values for the gravitino. For 10 MeV gre ater than or equal to mS/P greater than or equal to keV, the SN1987A o bservations can be used to exclude the gravitino masses in the range ( 10(-1.5) less than or equal to m(g) less than or equal to 30) eV, wher eas if m(S/P) less than or equal to keV, constraints of stellar energy loss can exclude the range (3 x 10(-6) less than or equal to m(g) les s than or equal to 50) eV for the photino mass equal to 100 GeV. We al so find that if m(S/P) less than or equal to MeV, present understandin g of big bang nucleosynthesis imply that m(g) greater than or equal to eV. These are the most severe bounds to date on mg in this class of m odels. (C) 1997 Published by Elsevier Science B.V.