ARE ANTIPROTONS FOREVER

Up to more than one million antiprotons from a single LEAR spill have been captured in a large Penning trap. Surprisingly, when the antiprot ons are cooled to energies significantly below 1 eV, the annihilation rate falls below the background. Thus, very long storage times for ant iprotons have been demonstrated in the trap, even at the compromised v acuum conditions imposed by the experimental setup. The significance f or future ultra-low-energy experiments is discussed.