Dark Matter in 3D

We discuss the relevance of directional detection experiments in the post-discovery era and propose a method to extract the local dark matter phase space distribution from directional data. The first feature of this method is a parameterization of the dark matter distribution function in terms of integrals of motion, which can be analytically extended to infer properties of the global distribution if certain equilibrium conditions hold. The second feature of our method is a decomposition of the distribution function in moments of a model independent basis, with minimal reliance on the ansatz for its functional form. We illustrate our method using the Via Lactea II N-body simulation as well as an analytical model for the dark matter halo. We conclude that O(1000) events are necessary to measure deviations from the Standard Halo Model and constrain or measure the presence of anisotropies.Comment: 36 pages, 13 figure

Neutrinoless double beta decay in seesaw models

We study the general phenomenology of neutrinoless double beta decay in seesaw models. In particular, we focus on the dependence of the neutrinoless double beta decay rate on the mass of the extra states introduced to account for the Majorana masses of light neutrinos. For this purpose, we compute the nuclear matrix elements as functions of the mass of the mediating fermions and estimate the associated uncertainties. We then discuss what can be inferred on the seesaw model parameters in the different mass regimes and clarify how the contribution of the light neutrinos should always be taken into account when deriving bounds on the extra parameters. Conversely, the extra states can also have a significant impact, cancelling the Standard Model neutrino contribution for masses lighter than the nuclear scale and leading to vanishing neutrinoless double beta decay amplitudes even if neutrinos are Majorana particles. We also discuss how seesaw models could reconcile large rates of neutrinoless double beta decay with more stringent cosmological bounds on neutrino masses.Comment: 34 pages, 5 eps figures and 1 axodraw figure. Final version published in JHEP. NME results available in Appendi

Multiple CP non-conserving mechanisms of (\u3b2\u3b2)0\u3bd -decay and nuclei with largely different nuclear matrix elements

We investigate the possibility to discriminate between different pairs of CP non-conserving mechanisms inducing the neutrinoless double beta (\u3b2\u3b2)0\u3bd -decay by using data on (\u3b2\u3b2) 0\u3bd -decay half-lives of nuclei with largely different nuclear matrix elements (NMEs). The mechanisms studied are: light Majorana neutrino exchange, heavy left-handed (LH) and heavy right-handed (RH) Majorana neutrino exchanges, lepton charge non-conserving couplings in SUSY theories with R-parity breaking giving rise to the "dominant gluino exchange" and the "squark-neutrino" mechanisms. The nuclei considered are 76Ge, 82Se, 100Mo, 130Te and 136Xe. Four sets of nuclear matrix elements (NMEs) of the decays of these five nuclei, derived within the Self-consistent Renormalized Quasiparticle Random Phase Approximation (SRQRPA), were employed in our analysis. While for each of the five single mechanisms discussed, the NMEs for 76Ge, 82Se, 100Mo and 130Te differ relatively little, the relative difference between the NMEs of any two nuclei not exceeding 10%, the NMEs for 136 Xe differ significantly from those of 76Ge, 82 Se, 100Mo and 130Te, being by a factor ~ (1.3 - 2.5) smaller. This allows, in principle, to draw conclusions about the pair of non-interfering (interfering) mechanisms possibly inducing the (\u3b2\u3b2)0\u3bd -decay from data on the half-lives of 136 Xe and of at least one (two) more isotope(s) which can be, e.g., any of the four, 76 Ge, 82 Se, 100 Mo and 130 Te. Depending on the sets of mechanisms considered, the conclusion can be independent of, or can depend on, the NMEs used in the analysis. The implications of the EXO lower bound on the half-life of 136 Xe for the problem studied are also exploited. \ua9 2013 SISSA, Trieste, Italy

A model of neutrino mass and dark matter with large neutrinoless double beta decay

We propose a model where neutrino masses are generated at three loop order but neutrinoless double beta decay occurs at one loop. Thus we can have large neutrinoless double beta decay observable in the future experiments even when the neutrino masses are very small. The model receives strong constraints from the neutrino data and lepton flavor violating decays, which substantially reduces the number of free parameters. Our model also opens up the possibility of having several new scalars below the TeV regime, which can be explored at the collider experiments. Additionally, our model also has an unbroken Z2 symmetry which allows us to identify a viable Dark Matter candidate

Neutrino mixing and leptonic CP violation from S 4 flavour and generalised CP symmetries

We consider a class of models of neutrino mixing with S4 lepton flavour symmetry combined with a generalised CP symmetry, which are broken to residual Z2 and Z2 7 HCP\u3bd symmetries in the charged lepton and neutrino sectors, respectively, HCP\u3bd being a remnant CP symmetry of the neutrino Majorana mass term. In this set-up the neutrino mixing angles and CP violation (CPV) phases of the neutrino mixing matrix depend on three real parameters \u2014 two angles and a phase. We classify all phenomenologically viable mixing patterns and derive predictions for the Dirac and Majorana CPV phases. Further, we use the results obtained on the neutrino mixing angles and leptonic CPV phases to derive predictions for the effective Majorana mass in neutrinoless double beta decay

Development of 100^{100}Mo-containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search

We report recent achievements in the development of scintillating bolometers to search for neutrinoless double-beta decay of $^{100}$Mo. The presented results have been obtained in the framework of the LUMINEU, LUCIFER and EDELWEISS collaborations, and are now part of the R\&D activities towards CUPID (CUORE Update with Particle IDentification), a proposed next-generation double-beta decay experiment based on the CUORE experience. We have developed a technology for the production of large mass ($\sim$1 kg), high optical quality, radiopure zinc and lithium molybdate crystal scintillators (ZnMoO$_4$ and Li$_2$MoO$_4$, respectively) from deeply purified natural and $^{100}$Mo-enriched molybdenum. The procedure is applied for a routine production of enriched crystals. Furthermore, the technology of a single detector module consisting of a large-volume ($\sim 100$~cm$^3$) Zn$^{100}$MoO$_4$ and Li$_2$$^{100}$MoO$_4$ scintillating bolometer has been established, demonstrating performance and radiopurity that are close to satisfy the demands of CUPID. In particular, the FWHM energy resolution of the detectors at 2615 keV --- near the $Q$-value of the double-beta transition of $^{100}$Mo (3034~keV) --- is $\approx$ 4--10~keV. The achieved rejection of $\alpha$-induced dominant background above 2.6~MeV is at the level of more than 99.9\%. The bulk activity of $^{232}$Th ($^{228}$Th) and $^{226}$Ra in the crystals is below 10 $\mu$Bq/kg. Both crystallization and detector technologies favor Li$_2$MoO$_4$, which was selected as a main element for the realization of a CUPID demonstrator (CUPID-0/Mo) with $\sim$7 kg of $^{100}$Mo