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SuperNEMO is the successor of the NEMO-3 experiment and will search for the hypothetical process of 0νββ by combining tracking and calorimetric measurements. The SuperNEMO calorimeter consists of 712 optical modules made of scintillator blocks directly coupled to photomultiplier tubes. 207Bi sources will be used to calibrate the energy scale of the calorimeter in dedicated calibration runs separated by a few weeks. In between these runs, a Light Injection (LI) system will guarantee the stability of the calorimetric response to 1%. The LI system injects pulsed LED light into each scintillator block via optical fibers. A reference optical module is used to monitor the light level against a 241Am source. The details of the LI system and its performance are presented.

The SuperNEMO Demonstrator, designed to search for double beta decay using enriched 82Se, has been assembled in the Modane Underground Laboratory under the French Alps. Thin foils with radio - purified and enriched 82Se are installed centrally in the detector. A novel foil fabrication method has been developed, improving the radiopurity achieved in the previous generation experiment. It consists of wrapping standalone selenium pads in raw Mylar, combined with selenium purified by a new reverse-chromatography method. This paper describes the features of these foils, their fabrication process, the characterization results, and the integration of the foils into the SuperNEMO Demonstrator.

The double-beta decay of 82Se to the 0+1 excited state of 82Kr has been studied with the NEMO-3 detector using 0.93 kg of enriched 82Se measured for 4.75 y, corresponding to an exposure of 4.42 kg y. A dedicated analysis to reconstruct the gamma-rays has been performed to search for events in the 2e2g channel. No evidence of a 2nbb decay to the 0+1 state has been observed and a limit of T2n 1/2(82Se; 0+gs -> 0+1) > 1.3 1021 y at 90% CL has been set. Concerning the 0nbb decay to the 0+1 state, a limit for this decay has been obtained with T0n 1/2(82Se; 0+g s -> 0+1) > 2.3 1022 y at 90% CL, independently from the 2nbb decay process. These results are obtained for the first time with a tracko-calo detector, reconstructing every particle in the final state.

SuperNEMO is a double-\\(\\beta\\) decay experiment, which will employ the successful tracker-calorimeter technique used in the recently completed NEMO-3 experiment. SuperNEMO will implement 100 kg of double-\\(\\beta\\) decay isotope, reaching a sensitivity to the neutrinoless double-\\(\\beta\\) decay (\\(0\\nu\\beta\\beta\\)) half-life of the order of \\(10^{26}\\) yr, corresponding to a Majorana neutrino mass of 50-100 meV. One of the main goals and challenges of the SuperNEMO detector development programme has been to reach a calorimeter energy resolution, \\(\\Delta\\)E/E, around 3%/\\(sqrt(E)\\)(MeV) \\(\\sigma\\), or 7%/\\(sqrt(E)\\)(MeV) FWHM (full width at half maximum), using a calorimeter composed of large volume plastic scintillator blocks coupled to photomultiplier tubes. We describe the R\\&D programme and the final design of the SuperNEMO calorimeter that has met this challenging goal.

The BiPo-3 detector, running in the Canfranc Underground Laboratory (Laboratorio Subterráneo de Canfranc, LSC, Spain) since 2013, is a low-radioactivity detector dedicated to measuring ultra low natural radionuclide contaminations of \\(^{208}\\)Tl (\\(^{232}\\)Th chain) and \\(^{214}\\)Bi (\\(^{238}\\)U chain) in thin materials. The total sensitive surface area of the detector is 3.6 m\\(^2\\). The detector has been developed to measure radiopurity of the selenium double \\(\\beta\\)-decay source foils of the SuperNEMO experiment. In this paper the design and performance of the detector, and results of the background measurements in \\(^{208}\\)Tl and \\(^{214}\\)Bi, are presented, and validation of the BiPo-3 measurement with a calibrated aluminium foil is discussed. Results of the \\(^{208}\\)Tl and \\(^{214}\\)Bi activity measurements of the first enriched \\(^{82}\\)Se foils of the double \\(\\beta\\)-decay SuperNEMO experiment are reported. The sensitivity of the BiPo-3 detector for the measurement of the SuperNEMO \\(^{82}\\)Se foils is \\(\\mathcal{A}\\)(\\(^{208}\\)Tl) \\(<2\\) \\(\\mu\\)Bq/kg (90\\% C.L.) and \\(\\mathcal{A}\\)(\\(^{214}\\)Bi) \\(<140\\) \\(\\mu\\)Bq/kg (90\\% C.L.) after 6 months of measurement.

Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay (\\(2\\nu\\beta\\beta\\)) half-life of \\(^{82}\\)Se as \\(T_{1/2}^{2\\nu} = \\left[ 9.39 \\pm 0.17\\,\\left(\\mbox{stat}\\right) \\pm 0.58\\,\\left(\\mbox{syst}\\right)\\right] \\times 10^{19}\\) y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is \\(\\left|M^{2\\nu}\\right| = 0.0498 \\pm 0.0016\\). In addition, a search for neutrinoless double beta decay (\\(0\\nu\\beta\\beta\\)) using 0.93 kg of \\(^{82}\\)Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of \\(T_{1/2}^{0\\nu} > 2.5 \\times 10^{23} \\,\\mbox{y} \\,(90\\%\\,\\mbox{C.L.})\\) for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of \\(\\langle m_{\\nu} \\rangle < \\left(1.2 - 3.0\\right) \\,\\mbox{eV}\\), where the range reflects \\(0\\nu\\beta\\beta\\) nuclear matrix element values from different calculations. Furthermore, constraints on lepton number violating parameters for other \\(0\\nu\\beta\\beta\\) mechanisms, such as right-handed currents, majoron emission and R-parity violating supersymmetry modes have been set.

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-\\(\\beta\\) decay of \\(^{150}\\)Nd using a total exposure of \\(0.19\\) kg\\(\\cdot\\)y recorded with the NEMO-3 detector at the Modane Underground Laboratory (LSM). We find no evidence of this decay and set lower limits on the half-life in the range \\(T_{1/2}>(1.1-3.2)\\times10^{21}\\) y at the \\(90\\%\\) CL, depending on the model used for the kinematic distributions of the emitted electrons.

The NEMO-3 experiment measured the half-life of the \\(2\\nu\\beta\\beta\\) decay and searched for the \\(0\\nu\\beta\\beta\\) decay of \\(^{116}\\)Cd. Using \\(410\\) g of \\(^{116}\\)Cd installed in the detector with an exposure of \\(5.26\\) y, (\\(4968\\pm74\\)) events corresponding to the \\(2\\nu\\beta\\beta\\) decay of \\(^{116}\\)Cd to the ground state of \\(^{116}\\)Sn have been observed with a signal to background ratio of about \\(12\\). The half-life of the \\(2\\nu\\beta\\beta\\) decay has been measured to be \\( T_{1/2}^{2\\nu}=[2.74\\pm0.04\\mbox{(stat.)}\\pm0.18\\mbox{(syst.)}]\\times10^{19}\\) y. No events have been observed above the expected background while searching for \\(0\\nu\\beta\\beta\\) decay. The corresponding limit on the half-life is determined to be \\(T_{1/2}^{0\\nu} \\ge 1.0 \\times 10^{23}\\) y at the \\(90\\) % C.L. which corresponds to an upper limit on the effective Majorana neutrino mass of \\(\\langle m_{\\nu} \\rangle \\le 1.4-2.5\\) eV depending on the nuclear matrix elements considered. Limits on other mechanisms generating \\(0\\nu\\beta\\beta\\) decay such as the exchange of R-parity violating supersymmetric particles, right-handed currents and majoron emission are also obtained.

We present results from a search for neutrinoless double-\\(\\beta\\) (\\(0\\nu\\beta\\beta\\)) decay using 36.6 g of the isotope \\(^{150}\\)Nd with data corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We construct a complete background model for this isotope, including a measurement of the two-neutrino double-\\(\\beta\\) decay half-life of \\(T^{2\\nu}_{1/2}=\\)[9.34 \\(\\pm\\) 0.22 (stat.) \\(^{+0.62}_{-0.60}\\) (syst.)]\\(\\times 10^{18}\\) y for the ground state transition, which represents the most precise result to date for this isotope. We perform a multivariate analysis to search for \\zeronu decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for \\zeronu decay is observed, we derive lower limits on half-lives for several mechanisms involving physics beyond the Standard Model. The observed lower limit, assuming light Majorana neutrino exchange mediates the decay, is \\(T^{0\\nu}_{1/2} >\\) 2.0 \\(\\times 10^{22}\\) y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of \\(\\langle m_{\\nu} \\rangle\\) \\(<\\) 1.6 - 5.3 eV..

The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double \\(\\beta\\) (\\(0\\nu\\beta\\beta\\)) decay. We report final results of a search for \\(0\\nu\\beta\\beta\\) decays with \\(6.914\\) kg of \\(^{100}\\)Mo using the entire NEMO-3 data set with a detector live time of \\(4.96\\) yr, which corresponds to an exposure of 34.3 kg\\(\\cdot\\)yr. We perform a detailed study of the expected background in the \\(0\\nu\\beta\\beta\\) signal region and find no evidence of \\(0\\nu\\beta\\beta\\) decays in the data. The level of observed background in the \\(0\\nu\\beta\\beta\\) signal region \\([2.8-3.2]\\) MeV is \\(0.44 \\pm 0.13\\) counts/yr/kg, and no events are observed in the interval \\([3.2-10]\\) MeV. We therefore derive a lower limit on the half-life of \\(0\\nu\\beta\\beta\\) decays in \\(^{100}\\)Mo of \\(T_{1/2}(0\\nu\\beta\\beta)> 1.1 \\times 10^{24}\\) yr at the \\(90\\%\\) Confidence Level, under the hypothesis of light Majorana neutrino exchange. Depending on the model used for calculating nuclear matrix elements, the limit for the effective Majorana neutrino mass lies in the range \\(\\langle m_{\\nu} \\rangle < 0.33\\)--\\(0.62\\) eV. We also report constraints on other lepton-number violating mechanisms for \\(0\\nu\\beta\\beta\\) decays.