New CUORICINO results and status of CUORE

University of Florence, Florens, Tuscany, Italy
Physics of Atomic Nuclei (Impact Factor: 0.51). 11/2006; 69(12):2083-2089. DOI: 10.1134/S1063778806120118


CUORICINO is an array of 62 TeO2 bolometers with a total mass of 40.7 kg (11.2 kg of 130Te), operated at about 10 mK to search for ββ(0ν) of 130Te. The detectors are organized as a 14-story tower and intended as a slightly modified version of one of the 19 towers of
the CUORE project, a proposed tightly packed array of 988 TeO2 bolometers (741 kg of total mass of TeO2) for ultralow-background searches on neutrinoless double-beta decay, cold dark matter, solar axions, and rare nuclear decays.
Started in April 2003 at the Laboratori Nazionali del Gran Sasso (LNGS), CUORICINO data taking was stopped in November 2003
to repair the readout wiring system of the 62 bolometers. Restarted in spring 2004, CUORICINO is presently the most sensitive
running experiment on neutrinoless double-beta decay. No evidence for ββ(0ν) decay has been found so far and a new lower limit, T


≥ 1.8 × 1024 yr (90% C.L.), is set, corresponding to 〈m
ν〉 ≤ 0.2–1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis. Detector performance, operational
procedures, and background analysis results are reviewed. The expected performance and sensitivity of CUORE is also discussed.

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    ABSTRACT: Renormalization group (RG) evolution of the neutrino mass matrix may take the value of the mixing angle theta13 very close to zero, or make it vanish. On the other hand, starting from theta13=0 at the high scale it may be possible to generate a nonzero theta13, radiatively. In the most general scenario with nonvanishing CP violating Dirac and Majorana phases, we explore the evolution in the vicinity of theta13=0, in terms of its structure in the complex Ue3 plane. This allows us to explain the apparent singularity in the evolution of the Dirac CP phase delta at theta13=0. We also introduce a formalism for calculating the RG evolution of neutrino parameters that uses the Jarlskog invariant and naturally avoids this singular behavior. We find that the parameters need to be extremely fine-tuned in order to get exactly vanishing theta13 during evolution. For the class of neutrino mass models with theta13=0 at the high scale, we calculate the extent to which RG evolution can generate a nonzero theta13, when the low energy effective theory is the standard model or its minimal supersymmetric extension. We find correlated constraints on theta13, the lightest neutrino mass m0, the effective Majorana mass mee measured in the neutrinoless double beta decay, and the supersymmetric parameter tanf beta.
    Physical review D: Particles and fields 04/2009; 79(7). DOI:10.1103/PhysRevD.79.076006 · 4.86 Impact Factor