Precision lifetime measurements of the 6[ital p][sup 2][ital P][sub 1/2,3/2] states in atomic cesium

We report measurements of the 6[ital p][sup 2][ital P][sub 1/2] and 6[ital p][sup 2][ital P][sub 3/2] state lifetimes in the [sup 133]Cs atom with precisions of 0.23% and 0.27%, respectively. The results are important to the interpretation of the next generation of parity nonconservation experiments in atomic cesium. A diode laser was used to selectively excite a fast beam of neutral cesium atoms. The decay in flight of the fluorescence was observed with photon-counting detectors. The lifetime results are 34.934[plus minus]0.094 ns for the 6[ital p][sup 2][ital P][sub 1/2] state and 30.499[plus minus]0.070 ns for the 6[ital p][sup 2][ital P][sub 3/2] state. We present comparisons with previous measurements and with relativistic many-body calculations of alkali-metal-atom transition matrix elements.