The Little Review on Leptogenesis

This is a brief review on the scenario of baryogenesis through leptogenesis. Leptogenesis is an appealing scenario that may relate the observed baryon asymmetry in the Universe to the low-energy neutrino data. In this review talk, particular emphasis is put on recent developments on the field, such as the flavourdynamics of leptogenesis and resonant leptogenesis near the electroweak phase transition. It is illustrated how these recent developments enable the modelling of phenomenologically predictive scenarios that can directly be tested at the LHC and indirectly in low-energy experiments of lepton-number and lepton-flavour violation.Comment: 15 pages, based on a plenary presentation given at the DISCRETE'08 Symposium, 11-16 December 2008, Valencia, Spai

Measurement of the beta beta Decay Half-Life of Te-130 with the NEMO-3 Detector

We report results from the NEMO-3 experiment based on an exposure of 1275 days with 661 g of Te-130 in the form of enriched and natural tellurium foils. The beta beta decay rate of Te-130 is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T-1/2(2v)=[7.0 +/- 0.9(stat) +/- 1: 1(syst)] x 10(20) yr. This represents the most precise measurement of this half- life yet published and the first real-time observation of this decay

Measurement of the double-β decay half-life of 150Nd and search for neutrinoless decay modes with the NEMO-3 detector

The half-life for double-β decay of 150Nd has been measured by the NEMO-3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of 150Nd, we measured the half-life for 2νββ decay to be T 2ν 1/2 = (9.11+0.25 −0.22(stat.) ± 0.63(syst.)) × 1018 yr. The observed limit on the half-life for neutrinoless double-β decay is found to be T 0ν 1/2 > 1.8 × 1022 yr at 90% confidence level. This translates into a limit on the effective Majorana neutrino mass of (mν ) < 4.0-6.3 eV if the nuclear deformation is taken into account. We also set limits on models involving Majoron emission, right-handed currents, and transitions to excited states

Search for Neutrinoless Double-Beta Decay of 100^{100}Mo with the NEMO-3 Detector

We report the results of a search for the neutrinoless double-$\beta$ decay (0$\nu\beta\beta$) of $^{100}$Mo, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg.y, no evidence for the 0$\nu\beta\beta$ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of $T_{1/2}(0\nu\beta\beta)>1.1 \times 10^{24}$ years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the Nuclear Matrix Elements this corresponds to an upper limit on the Majorana effective neutrino mass of $< 0.3-0.8$ eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0$\nu\beta\beta$ decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2-10] MeV is observed for an exposure of 47 kg.y

Measurement of double beta decay of 150^{150}Nd to the 01+^+_1 excited state of 150^{150}Sm in NEMO-3

NEMO-3 results for the double beta decay of $^{150}$Nd to the 0 $^+_1$ and 2$^+_1$ excited states of $^{150}$Sm are reported. The data recorded during 5.25 y with 36.6 g of the isotope $^{150}$Nd were used in the analysis. For the first time the signal of $2\nu\beta\beta$ transition to the 0$^+_1$ excited state is detected with statistical significance exceeding 5 sigma. The half-life is measured to be T_{1/2}^{2\nu\beta\beta}(0^+_1) = \left[ 1.11 ^{+0.19}_{-0.14} \,\left(\mbox{stat}\right) ^{+0.17}_{-0.15}\, \left(\mbox{syst}\right) \right] \times10^{20}\,\mbox{y}. Limits are set on $2\nu\beta\beta$ decay to 2$^+_1$ level and on $0\nu\beta\beta$ decay to 0$^+_1$ and 2$^+_1$ levels of $^{150}$Sm.Comment: Withdrawn for revision. To be resubmitted late

Measurement of the 2νββ decay half-life and search for the 0νββ decay of 116Cd with the NEMO-3 detector

International audienc

Standardizing the New E-Business Platform: Learning From the EDI Experience

International audienceThe full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of$^{100}$ Mo to the ground state of$^{100}$ Ru, $T_{1/2} = \left[ 6.81 \pm 0.01\,\left( \text{ stat }\right) ^{+0.38-0.40}\,\left( \text{ syst }\right) \right] \times 10^{18}$  year. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $5\times 10^5$ events and a signal-to-background ratio of $\sim$ 80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of $\mathrm{n}=2,3,7$ , as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained

Measurement of the 2νββ\nu\beta\beta decay half-life of 150^{150}Nd and a search for 0νββ\nu\beta\beta decay processes with the full exposure from the NEMO-3 detector

We present results from a search for neutrinoless double-β (0νββ) decay using 36.6 g of the isotope Nd150 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-β decay half-life of T1/22ν=[9.34±0.22(stat) -0.60+0.62(syst)]×1018  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 0νββ decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for 0νββ 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 T1/20ν>2.0×1022  y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of ⟨mν⟩<1.6–5.3  eV

Search for Periodic Modulations of the Rate of Double-Beta Decay of 100^{100}Mo in the NEMO-3 Detector

International audienceDouble-beta decays of Mo100 from the 6.0195-year exposure of a 6.914 kg high-purity sample were recorded by the NEMO-3 experiment that searched for neutrinoless double-beta decays. These ultrarare transitions to Ru100 have a half-life of approximately 7×1018 years and have been used to conduct the first-ever search for periodic variations of this decay mode. The Lomb-Scargle periodogram technique, and its error-weighted extension, were employed to look for periodic modulations of the half-life. Data show no evidence at the 95% confidence level of modulations with amplitude greater than 2.5% in the frequency range of 0.33225yr−1 to 360yr−1