Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector.

  title={Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector.},
  author={N. Ackerman and B. Aharmim and M. Auger and D. Auty and P. Barbeau and K. Barry and L. Bartoszek and E. Beauchamp and V. Belov and C. Benitez-Medina and M. Breidenbach and A. Burenkov and B. Cleveland and R. Conley and E. Conti and J. Cook and S. Cook and A. Coppens and I. Counts and W. Craddock and T. Daniels and M. Danilov and C. G. Davis and J. Davis and R. DeVoe and Z. Djurcic and A. Dobi and A. Dolgolenko and M. Dolinski and K. Donato and M. Dunford and W. Fairbank and J. Farine and P. Fierlinger and D. Franco and D. Freytag and G. Giroux and R. Gornea and K. Graham and G. Gratta and M. Green and C. H{\"a}gemann and C. Hall and K. Hall and G. Haller and C. Hargrove and R. Herbst and S. Herrin and J. Hodgson and M. Hughes and A. Johnson and A. Karelin and L. Kaufman and T. Koffas and A. Kuchenkov and A. Kumar and K. Kumar and D. Leonard and F. Leonard and F. Leport and D. Mackay and R. Maclellan and M. Marino and Y. Martin and B. Mong and M. M. Diez and P. Morgan and A. M{\"u}ller and R. Neilson and R. Nelson and A. Odian and K. O'Sullivan and C. Ouellet and A. Piepke and A. Pocar and C. Prescott and K. Pushkin and A. Rivas and E. Rollin and P. Rowson and J. Russell and A. Sabourov and D. Sinclair and K. Skarpaas and S. Slutsky and V. Stekhanov and V. Strickland and M. Swift and D. Tosi and K. Twelker and P. Vogel and J. Vuilleumier and J. Vuilleumier and A. Waite and S. Waldman and T. Walton and K. Wamba and M. Weber and U. Wichoski and J. Wodin and J. D. Wright and L. Yang and Y. Yen and O. Zeldovich},
  journal={Physical review letters},
  volume={107 21},
We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino… Expand

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