We have limited a CPT-violating correlation in annihilations of polarized ortho-positronium. We searched for an asymmetry in the triple correlations dot k1 cross k2, where k1 and k2 are the two largest photon momenta, and s is the spin of the positronium. Using the Gammasphere array of Compton-suppressed high-purity germanium detectors, we detected 2.65e7 events of ortho-Ps annihila tion. The amplitude of a CPT-violating asymmetry in the data set is found to be 0.0026 plus or minus 0.0031, a factor of 6 smaller than previous experiments.

CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless

double beta decay and other rare processes, including double beta decay with two neutrinos

(2νββ). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO₂ crystals arranged in a tower and operated at a temperature of ∼10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors.

The experiment included 4 enriched crystals, 2 enriched with ¹³⁰Te and 2 with ¹²⁸Te, in order to aid in the measurement of the 2νββ rate. The enriched crystals contained a total of ∼350 g ¹³⁰Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130-enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2νββ half-life was measured to be T_1/2 = [9.81 ± 0.96(stat) ± 0.49(syst)]×

10²⁰ y.

This dissertation describes a measurement of the neutrino oscillation parameters $Delta m^2_{21}$, $theta_{12}$ and constraints on $theta_{13}$ based on a study of reactor antineutrinos at a baseline of $sim 180,$km with the KamLAND detector. The data presented here was collected between April 2002 and November 2009, and amounts to a total exposure of $2.64 \pm 0.07 times 10^{32}$ proton-years. For this exposure we expect $2140 \pm 74 (syst)$ antineutrino candidates from reactors, assuming standard model neutrino behavior, and $350 pm 88 (syst)$ candidates from background. The number observed is 1614. The ratio of background-subtracted candidates observed to expected is

$$frac{N_{Obs}-N_{Bkg}}{N_{Exp}} = 0.59 \pm 0.02 (stat)\pm 0.045 (syst)nonumber$$

which confirms reactor neutrino disappearance at greater than 5$sigma$ significance. Interpreting this deficit as being due to neutrino oscillation, the best-fit oscillation parameters from a three-flavor analysis are $Delta m^{2}_{21} = 7.60 ^{+0.20}_{-0.19} times 10^{-5} rm{eV^2}$, mbox{$theta_{12} = 32.5 \pm 2.9$ degrees} and $sin^{2}theta_{13} = 0.025 ^{+0.035}_{-0.035}$, the 95% confidence-level upper limit on $sin^{2}theta_{13}$ is mbox{$sin^{2}theta_{13}<0.083 $}. Assuming textit{CPT} invariance, a combined analysis of KamLAND and solar neutrino data yields best-fit values: $Delta m^{2}_{21} = 7.60 ^{+0.20}_{-0.20} times 10^{-5} rm{eV^2}$, $theta_{12} = 33.5 ^{+1.0}_{-1.1}$ degrees, and $sin^{2}theta_{13} = 0.013 pm {0.028}$ or $sin^{2}theta_{13}<0.06 $ at the 95% confidence level.

Results from non-accelerator neutrino oscillation experiments have provided evidence for the oscillation of massive neutrinos. The subdominant oscillation, the coupling of the electron neutrino flavor to the third mass eigenstate, has not been measured yet. The size of this coupling U_e3 and its corresponding mixing angle theta_13 are critical for CP violation searches in the lepton sector and will define the future of accelerator neutrino physics. The current best limit on U_e3 comes from the CHOOZ reactor neutrino disappearance experiment. In this talk we review proposals for future measurements of theta13 with reactor antineutrinos.

We have measured the mbox beta - nu correlation coefficient, a_beta nu, in 21Na using a laser-trapped sample. We measure the energy spectrum of the recoil nuclei by measuring their time-of-flight in coincidence with the atomic electrons shaken off in beta decay. High detection efficiency of these low-energy electrons allows good counting statistics, even with low trap density, which suppresses the photoassociation of molecular sodium, which can cause a large systematic error. Our measurement, with a 1 percent fractional uncertainty, agrees with the Standard Model prediction but disagrees with our previous measurement which was susceptible to error introduced by molecular sodium. We summarize precise measurements of a_ beta nu and their consequences for searches for Beyond Standard Model scalar and tensor current couplings.