Probing CPT violation with atmospheric neutrinos

We investigate the recently suggested scheme of independent mass matrices for neutrinos and antineutrinos. Such a CPT violating scheme is able to account for all neutrino data with the three known flavors. For atmospheric neutrinos this means that it is possible to have different mass squared differences driving the oscillation for neutrinos and antineutrinos. We analyze the atmospheric and K2K data within the simplest scheme of two neutrino oscillation, neglecting electron neutrino oscillation. We find that the preferred region is close to the CPT conserving mass spectra. However the spectra with the antineutrino mass squared difference about or larger than 0.1 eV^2 and the neutrino mass squared difference about 2 \times 10^{-3} eV^2 is not significantly disfavored. In this parameter region the atmospheric data are independent of the antineutrino mass squared difference. Therefore no useful constraint can be put on CPT violation effects contributing to different masses for the neutrinos and antineutrinos.Comment: 8 pages, 2 figures. v3: Improved analysis, References adde

Combining LSND and Atmospheric Anomalies in a Three-Neutrino Picture

We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. We find the region in the parameter space that provides a good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ constraint. We demonstrate that the goodness of this fit is comparable to that of the conventional fit to the solar and atmospheric data. Large values of the LSND angle are favoured and $\sin^2(2\theta_{\rm LSND})$ can be as high as 0.1. This can have important effects on the atmospheric electron neutrino ratios as well as on down-going multi-GeV muon neutrino ratios. We examine the possibility of distinguishing this scheme from the conventional one at the long baseline experiments. We find that the number of electron neutrino events observed at the CERN to Gran Sasso experiment may lead us to identify the scheme, and hence the mass pattern of neutrinos

Degenerate neutrinos from a supersymmetric A_4 model

We investigate the supersymmetric A_4 model recently proposed by Babu, Ma and Valle. The model naturally gives quasi-degenerate neutrinos that are bi-largely mixed, in agreement with observations. Furthermore, the mixings in the quark sector are constrained to be small, making it a complete model of the flavor structure. Moreover, it has the interesting property that CP-violation in the leptonic sector is maximal (unless vanishing). The model exhibit a close relation between the slepton and lepton sectors and we derive the slepton spectra that are compatible with neutrino data and the present bounds on flavor-violating charged lepton decays. The prediction for the branching ratio of the decay tau -> mu gamma has a lower limit of 10^{-9}. In addition, the overall neutrino mass scale is constrained to be larger than 0.3 eV. Thus, the model will be tested in the very near future.Comment: 11 pages, 6 figures. Talk given at the International Workshop on Astroparticle and High Energy Physics (AHEP), Valencia, Spain, 14-18 Oct. 200

Neutrinos that violate CPT, and the experiments that love them

Recently we proposed a framework for explaining the observed evidence for neutrino oscillations without enlarging the neutrino sector, by introducing CPT violating Dirac masses for the neutrinos. In this paper we continue the exploration of the phenomenology of CPT violation in the neutrino sector. We show that our CPT violating model fits the existing SuperKamiokande data at least as well as the standard atmospheric neutrino oscillation models. We discuss the challenge of measuring CP violation in a neutrino sector that also violates CPT. We point out that the proposed off-axis extension of MINOS looks especially promising in this regard. Finally, we describe a method to compute CPT violating neutrino effects by mocking them up with analog matter effects.Comment: 17 pages, 3 eps figure

Beta-amino acid transport in pig small intestine in vitro by a high-affinity, chloride-dependent carrier

AbstractThis study describes unidirectional influx of amino acids and d-glucose across the small intestinal brush-border membrane of fully weaned eight week old pigs. Influx is minimal in the duodenum and maximal in the distal and/or mid small intestine. Influx of β-alanine, taurine and N-ethyl-aminoisobutyric acid is chloride-dependent. The activation stoichiometry for taurine influx is 1.0 ± 0.2 chloride/2.4 ± 0.3 sodium/ 1 taurine. Influx of D-glucose, lysine, glycine and glutamate is chloride-independent. An ABC test demonstrates a common β-amino acid carrier: (a) the apparent affinity constant K12Taurine is 44 ± 13 μM (means ± S.D.) and the inhibitory constant (KiTaurine) against β-alanine influx is 41 ± 5 μM (means ± S.E.). (b) K12β-alanine is 97 ± 23 μM and Kiβ-alanine against taurine influx is 160 ± 22 μM. (c) KiHypotaunne against taurine and β-alanine influx is 43 ± 4 (n = 7) and 22 ± 5 μM (n = 7), respectively. In conclusion, a high affinity, low capacity, sodium- and chloride-dependent carrier of β-amino acids is present in pig small intestine