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Physics Letters B

Test of the exponential decay law at short decay times using tau leptons

G. Alexander, John E. Allison, N. Altekamp, K. Ametewee, K. J. Anderson, S. Anderson, S. Arcelli, S. Asai, D. A. Axen, G. Azuelos, Austin H. Ball, E. L. Barberio, Roger John Barlow, R. Bartoldus, J. R. Batley, G. Beaudoin, J. Bechtluft, G.A. Beck, Christine Beeston, T. Behnke, A. N. Bell, K. W. Bell, G. Bella, S. Bentvelsen, P. Berlich, Siegfried Bethke A, O. Biebel, I.J. Bloodworth, J. E. Bloomer, P. Bock, H. M. Bosch, M. Boutemeur, B. T. Bouwens, S. Braibant, P. Bright-Thomas, R. M. Brown, H. Burckhart, C. Burgard, R. Bürgin, P. Capiluppi, R.K. Carnegie, A. A. Carter, J.R. Carter, C.Y. Chang, C. E. K. Charlesworth, D. G. Charlton, David Chrisman, S. L. Chu, P. E. L. Clarke, S. G. Clowes, I. Cohen, J.E. Conboy, O. C. Cooke, M. Cuffiani, S. Dado, Carlo Dallapiccola, G. M. Dallavalle, C. Darling, S. J. de Jong, L.A. del Pozo, M.S. Dixit, E. do Couto e Silva, E. Duchovni, G. Duckeck, I. P. Duerdoth, U. C. Dunwoody, J. E. G. Edwards, P.G. Estabrooks, H. G. Evans, F. Fabbri, B. Fabbro, P. Fath, F. Fiedler, Massimiliano Fierro, M. Fincke-Keeler, H.M. Fischer, R. Folman, D.G. Fong, Maurice Emile Foucher, H. Fukui, A. Fürtjes, P. Gagnon, A. Gaidot, J. William Gary, Jules Gascon, S. Gascon-Shotkin, N.I. Geddes, Ch. Geich-Gimbel, S.W. Gensler, F. X. Gentit, T. Geralis, G. Giacomelli, P. Giacomelli, R. Giacomelli, V. Gibson, W.R. Gibson, DOUGLAS M. GINGRICH, Jacques Goldberg, M.J. Goodrick, W. Gorn

Published Feb 1, 1996• 12 citations

DOI: 10.1016/0370-2693(95)01540-x

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We evaluate numerically the survival probability P(t) for the unstable 2P excited state of the hydrogen atom that decays into the ground-state 1S by emitting one photon (τ ≈ 1.595 ns), thus extending the analytic study of Facchi and Pascazio, Phys. Lett. A 241, 139 (1998). To this end, we first determine the analytic expression of the spectral function of the unstable state, which allows for an accurate evaluation of P(t). As expected, for short and long time scales, P(t) shows deviations from the exponential law: a 'Zeno' region occurs at extremely short times (up to ≈ 0.3 attosec), followed by a longer 'anti-Zeno' domain (up to ≈ 50 attosec); at long times above 125 τ the decay law scales as t-4.