B. Search for 0 νββ decay No evidence for 0 νββ decay was found for all seven isotopes. The associated limits are presented in Table 3. The 0 νββ -decay search in NEMO 3 is most promising with $^{100}$Mo and $^{82}$Se because of the larger available sample mass and high enough Q$_{ββ}$ ∼ 3 MeV. The data taken from February 2003 till the end of 2008 has been used in the search for neutrinoless double beta decay. The data corresponds to 1409 effective days of data collection. For the case of the mass mechanism, the 0 νββ -decay signal is expected to be a peak in the energy sum distribution at the position of the transition energy Q$_{ββ}$ . The two-electron energy sum spectra for $^{100}$Mo and $^{82}$Se are shown in Fig. 2 and Fig. 3 demonstrating a good agreement between observed and expected number of events. Since no excess is observed at the tail of the distributions, limits are set on the neutrinoless double beta decay with the CL$_{s}$ method based on the use of a log-likelihood ratio (LLR) test statistics [19]. This gives the lower limits on the half-life of T 0 ν 1 / $_{2}$( $^{100}$Mo ) > 1 . 1 · 10 $^{24}$yr (90% C.L.) and T 0 ν 1 / $_{2}$( $^{82}$Se ) > 3 . 6 · 10 $^{23}$yr (90% C.L.) A lower half-life limit translates into an upper limit on the effective Majorana neutrino mass 〈 m$_{ν}$ 〉 . According to the recent results of different theoretical NME calculations (see Table 4) the half-life limit obtained for $^{100}$Mo 7 Isotope Measurement T$_{1}$$_{/}$$_{2}$ (0 ν ), y time, days $^{100}$Mo 1409 > 1 . 1 · 10 24 y $^{82}$Se 1409 > 3 . 6 · 10 23 y $^{130}$Te 1221 > 1 · 10 23 y $^{150}$Nd 939 > 1 . 8 · 10 22 y $^{116}$Cd 77 > 1 . 6 · 10 22 y $^{48}$Ca 943.16 > 1 . 3 · 10 22 y $^{96}$Zr 1221 > 9 . 2 · 10 21 y TABLE III: Limits at 90% C.L. on 0 νββ decay (neutrino mass mechanism) for different nuclei obtained in the NEMO 3 experiment.