Author/Authors :
Juhلsz، نويسنده , , B. and Barna، نويسنده , , D. and Eades، نويسنده , , J. J. Fuhrmann، نويسنده , , H. and Hayano، نويسنده , , R.S and Hori، نويسنده , , M. and Horvلth، نويسنده , , D. and Torii، نويسنده , , H.A and Widmann، نويسنده , , E. and Yamaguchi، نويسنده , , H. and Yamazaki، نويسنده , , T. and Zmeskal، نويسنده , , J.، نويسنده ,
Abstract :
The temperature dependence of the quenching cross section of two long-lived metastable states of antiprotonic helium, in collisions with hydrogen and deuterium molecules, has been measured. In the case of the state (n, l) = (37, 34), the cross section decreases with decreasing temperature until it levels off below ∼30 K, showing a quantum tunneling effect with a small activation barrier. In the case of the state (39, 35), on the other hand, for which the lack of an activation barrier was predicted theoretically, the quenching cross section increases slightly with decreasing temperature, indicating the 1/v Wigner threshold law of exothermic reactions involving neutral particles.
