Blackbody radiation shift of the 133Cs hyperfine transition frequency -: art. no. 053401

We report the theoretical evaluations of the static scalar polarizability of the Cs-133 ground state and of the blackbody radiation shift induced on the transition frequency between the two hyperfine levels with m(F)=0. This shift is of fundamental importance in the evaluation of the accuracy of the primary frequency standards based on atomic fountains and is employed in the realization of the SI second in the International Atomic Time scale at the level of 1x10(-15). Our computed value for the polarizability is alpha(0)=(6.600+/-0.016)x10(-39)C m(2)/V in agreement at the level of 1x10(-3) with recent theoretical and experimental values. As regards the blackbody radiation shift we find for the relative hyperfine transition frequency beta=(-1.49+/-0.07)x10(-14) at T=300 K in agreement with frequency measurements reported by our group and by Bauch and Schroder [Phys. Rev. Lett. 78, 622 (1997)]. This value is lower by 2x10(-15) than that obtained with measurements based on the dc Stark shift and than the value commonly accepted up to now.