Neutrino Mass and Oscillations

Current evidence for neutrino oscillation is reviewed, some areas for closer investigation are suggested, and a plausible future experimental program is summarized.Comment: Text of talk presented at Lepton-Photon 99 Conference, Stanford, Aug. 9-14, 1999; to be published in the Proceedings. LaTeX, 22 pages, 4 figures, 6 Postscript file

Direct Measurement of Neutrino Mass

The sum of the masses of the three neutrino mass eigenstates is now constrained both from above and below, and lies between 55 and 6900 meV. The lower limit is set by neutrino oscillations and the fact that masses are non-negative. The upper limit is set by laboratory measurements on the beta decay of tritium. These determinations share a common characteristic of being essentially model independent, or "direct." The clustering on large scales in the universe depends on this quantity, and, within the framework of Lambda-CDM cosmology, favors a mass sum below about 600 meV. In this article, the laboratory approach to neutrino mass via beta decay is emphasized, particularly an experiment now under construction, KATRIN, on the beta decay of tritium. Another candidate beta-active nuclide, Re-187, offers an advantage in phase space but calls for a very different experimental approach.Comment: 6 pages, 2 figures, for Proceedings of Carolina International Symposium on Neutrino Physics, Columbia, SC, May 15-17, 2008. To be published in J.Phys.: Conf. Serie

Extremal extensions of entanglement witnesses: Unearthing new bound entangled states

In this paper, we discuss extremal extensions of entanglement witnesses based on Choi's map. The constructions are based on a generalization of the Choi map due to Osaka, from which we construct entanglement witnesses. These extremal extensions are powerful in terms of their capacity to detect entanglement of positive under partial transpose (PPT) entangled states and lead to unearthing of entanglement of new PPT states. We also use the Cholesky-like decomposition to construct entangled states which are revealed by these extremal entanglement witnesses.Comment: 8 pages 6 figures revtex4-

Simultaneous minimum-uncertainty measurement of discrete-valued complementary observables

We have made the first experimental demonstration of the simultaneous minimum uncertainty product between two complementary observables for a two-state system (a qubit). A partially entangled two-photon state was used to perform such measurements. Each of the photons carries (partial) information of the initial state thus leaving a room for measurements of two complementary observables on every member in an ensemble.Comment: 4 pages, 4 figures, REVTeX, submitted to PR

Constraining the Leading Weak Axial Two-body Current by SNO and Super-K

We analyze the Sudbury Neutrino Observatory (SNO) and Super-Kamiokande (SK) data on charged current (CC), neutral current (NC) and neutrino electron elastic scattering (ES) reactions to constrain the leading weak axial two-body current parameterized by L_1A. This two-body current is the dominant uncertainty of every low energy weak interaction deuteron breakup process, including SNO's CC and NC reactions. Our method shows that the theoretical inputs to SNO's determination of the CC and NC fluxes can be self-calibrated, be calibrated by SK, or be calibrated by reactor data. The only assumption made is that the total flux of active neutrinos has the standard ^8B spectral shape (but distortions in the electron neutrino spectrum are allowed). We show that SNO's conclusion about the inconsistency of the no-flavor-conversion hypothesis does not contain significant theoretical uncertainty, and we determine the magnitude of the active solar neutrino flux

Closed Trapped Surfaces in Cosmology

The existence of closed trapped surfaces need not imply a cosmological singularity when the spatial hypersurfaces are compact. This is illustrated by a variety of examples, in particular de Sitter spacetime admits many closed trapped surfaces and obeys the null convergence condition but is non-singular in the k=+1 frame.Comment: 11 pages. To appear in GRG, Vol 35 (August issue

Solar Neutrinos from CNO Electron Capture

The neutrino flux from the sun is predicted to have a CNO-cycle contribution as well as the known pp-chain component. Previously, only the fluxes from beta+ decays of 13N, 15O, and 17F have been calculated in detail. Another neutrino component that has not been widely considered is electron capture on these nuclei. We calculate the number of interactions in several solar neutrino detectors due to neutrinos from electron capture on 13N, 15O, and 17F, within the context of the Standard Solar Model. We also discuss possible non-standard models where the CNO flux is increased.Comment: 4 pages, 1 figure, submitted to Phys. Rev. C; v2 has minor changes including integration over solar volume and addition of missing reference to previous continuum electron capture calculation; v3 has minor changes including addition of references and the correction of a small (about 1%) numerical error in the table