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

@article{Ackerman2011ObservationOT, 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}, year={2011}, volume={107 21}, pages={ 212501 } }

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

#### 129 Citations

Search for neutrinoless double-beta decay in 136Xe with EXO-200.

- Physics, Medicine
- Physical review letters
- 2012

This work sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νββ)(136Xe)>1.6×10(25) yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation. Expand

First 0νββ results from EXO-200

- Physics
- 2013

Abstract We report on a search for neutrinoless double-beta decay of 136 Xe with EXO-200. No signal is observed for a 136 Xe exposure of 26.3 kg-yr, with a background of ∼ 1.5 × 10 − 3 kg ( e n r LXe… Expand

Search for neutrino-less double beta decay with EXO-200 and prospects for Ba ion tagging

- Physics
- 2013

The Enriched Xenon Observatory collaboration searches for neutrino-less double beta decay in 136Xe. The first phase of the experiment, EXO-200 has started taking data in 2011 and has already produced… Expand

Shell Model description of the ββ decay of 136Xe

- Physics
- 2012

Abstract We study in this Letter the double beta decay of 136Xe with emission of two neutrinos which has been recently measured by the EXO-200 Collaboration. We use the same shell model framework,… Expand

Double Beta Decay Experiments: Beginning of a New Era

- Physics
- 2012

Interest in neutrinoless double beta decay (0νββ) has seen a significant renewal in the recent 10 years after evidence for neutrino oscillations was obtained from the results of atmospheric, solar,… Expand

Two neutrino double-beta decay and effective axial-vector coupling constant

- Physics
- 2018

The theoretical and experimental study of the two-neutrino double-beta decay (2νββ -decay) is of crucial importance for reliable calculation of matrix elements governing the neutrinoless double-beta… Expand

Searches for neutrinoless double beta decay

- Physics
- 2012

Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a… Expand

Search for Majorana neutrinos with the first two years of EXO-200 data

- Medicine, Physics
- Nature
- 2014

New results from EXO-200 based on a large 136Xe exposure are reported, finding no statistically significant evidence for 0νββ decay and set a half-life limit of 1.1 × 1025 years at the 90 per cent confidence level. Expand

Neutrinoless double beta decay experiments

- Physics
- 2014

Neutrinoles double beta decay is the only process known so far able to test the neutrino intrinsic nature: its experimental observation would imply that the lepton number is violated by two units and… Expand

Nuclear Matrix Element for Two Neutrino Double Beta Decay from 136Xe

- Physics
- 2012

The nuclear matrix element for the two neutrino double beta decay (2νββ) of 136 Xe → 136 Ba was evaluated by fermi surface quasi particle model (FSQP), where experimental GT strengths measured by the… Expand

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