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

Morphology, carbohydrate distribution, gene expression, and enzymatic activities related to cell wall hydrolysis in four barley varieties during simulated malting

Many biological processes, such as cell wall hydrolysis and the mobilisation of nutrient reserves from the starchy endosperm, require stringent regulation to successfully malt barley (Hordeum vulgare) grain in an industrial context. Much of the accumulated knowledge defining these events has been collected from individual, unrelated experiments, and data have often been extrapolated from Petri dish germination, rather than malting, experiments. Here, we present comprehensive morphological, biochemical, and transcript data from a simulated malt batch of the three elite malting cultivars Admiral, Navigator, and Flagship, and the feed cultivar Keel. Activities of lytic enzymes implicated in cell wall and starch depolymerisation in germinated grain have been measured, and transcript data for published cell wall hydrolytic genes have been provided. It was notable that Flagship and Keel exhibited generally similar patterns of enzyme and transcript expression, but exhibited a few key differences that may partially explain Flagship's superior malting qualities. Admiral and Navigator also showed matching expression patterns for these genes and enzymes, but the patterns differed from those of Flagship and Keel, despite Admiral and Navigator having Keel as a common ancestor. Overall (1,3;1,4)-β-glucanase activity differed between cultivars, with lower enzyme levels and concomitantly higher amounts of (1,3;1,4)-β-glucan in the feed variety, Keel, at the end of malting. Transcript levels of the gene encoding (1,3;1,4)-β-glucanase isoenzyme EI were almost three times higher than those encoding isoenzyme EII, suggesting a previously unrecognised importance for isoenzyme EI during malting. Careful morphological examination showed that scutellum epithelial cells in mature dry grain are elongated but expand no further as malting progresses, in contrast to equivalent cells in other cereals, perhaps demonstrating a morphological change in this critical organ over generations of breeding selection. Fluorescent immuno-histochemical labelling revealed the presence of pectin in the nucellus and, for the first time, significant amounts of callose throughout the starchy endosperm of mature grain.Natalie S. Betts, Laura G. Wilkinson, Shi F. Khor, Neil J. Shirley, Finn Lok, Birgitte Skadhauge, Rachel A. Burton, Geoffrey B. Fincher and Helen M. Collin

CPT Violation and the Nature of Neutrinos

In order to accommodate the neutrino oscillation signals from the solar, atmospheric, and LSND data, a sterile fourth neutrino is generally invoked, though the fits to the data are becoming more and more constrained. However, it has recently been shown that the data can be explained with only three neutrinos, if one invokes CPT violation to allow different masses and mixing angles for neutrinos and antineutrinos. We explore the nature of neutrinos in such CPT-violating scenarios. Majorana neutrino masses are allowed, but in general, there are no longer Majorana neutrinos in the conventional sense. However, CPT-violating models still have interesting consequences for neutrinoless double beta decay. Compared to the usual case, while the larger mass scale (from LSND) may appear, a greater degree of suppression can also occur.Comment: 10 pages, 1 figur

Resonant flavor conversion of supernova neutrinos and neutrino parameters

The unknown neutrino parameters may leave detectable signatures in the supernova (SN) neutrino flux. However, even the contribution from the MSW flavor transition alone could cause ambiguity in the interpretation to the neutrino signals because of the uncertain local density profile of the SN matter and the model-dependent SN neutrino spectral parameters. A specific parametrization to the unknown local density profile is proposed in this work, and the contribution from the standard MSW effect is investigated through a multi-detector analysis of the SN neutrinos. In establishing the model-independent scheme, results based on the existing spectral models are included. The limitation of the analysis is also discussed.Comment: Revised, 14 pages, 7 figure

Non-Abelian Discrete Symmetries and Neutrino Masses: Two Examples

Two recent examples of non-Abelian discrete symmetries (S_3 and A_4) in understanding neutrino masses and mixing are discussed.Comment: 16 pages, no figure, invited contribution to NJP focus issue on neutrino

Effect of indomethacin on S. typhimurium and cholera toxin-induced fluid accumulation in pig jejunum

We have investigated the influence of prostaglandins (PGs) on the Salmonella typhimurium (St) and cholera toxin (CT)-induced fluid accumulation in jejunum of 9-10 weeks (18-20 kg) old female pigs. St (1010 colony forming units) and CT (56/ig) were instilled in separated tiedoff loops for 8 hours. Before instillation, and again after 4 hours, pigs were given an intravenous dose of the cyclooxygenase and prostaglandin synthesis inhibitor, indomethacin, or saline alone (control). In the St-loops indomethacin had no effect on the fluid accumulation, 9.1 ± 1.3 vs 8.2±0.5 mg fluid/mg loop dry weight, whereas in CT-Ioops, indomethacin reduced fluid accumulation significantly from 35±2 to 22±3 mg fluid/mg loop dry weight (P\u3c0.05). Our preliminary results indicate that PGs are not involved in St-induced fluid accumulation in pig jejunum, which is in contrast to the case in CT -induced fluid accumulation

LHC signals for neutrino mass model in bilinear R-parity violating mAMSB

We investigate a neutrino mass model in which the neutrino data is accounted for by bilinear R-parity violating supersymmetry with anomaly mediated supersymmetry breaking. We focus on the CERN Large Hadron Collider (LHC) phenomenology, studying the reach of generic supersymmetry search channels with leptons, missing energy and jets. A special feature of this model is the existence of long lived neutralinos and charginos which decay inside the detector leading to detached vertices. We demonstrate that the largest reach is obtained in the displaced vertices channel and that practically all of the reasonable parameter space will be covered with an integrated luminosity of 10 fb-1. We also compare the displaced vertex reaches of the LHC and Tevatron.Comment: 27 page

A Simplest A4 Model for Tri-Bimaximal Neutrino Mixing

We present a see-saw $A_4$ model for Tri-Bimaximal mixing which is based on a very economical flavour symmetry and field content and still possesses all the good features of $A_4$ models. In particular the charged lepton mass hierarchies are determined by the $A_4\times Z_4$ flavour symmetry itself without invoking a Froggatt-Nielsen U(1) symmetry. Tri-Bimaximal mixing is exact in leading order while all the mixing angles receive corrections of the same order in next-to-the-leading approximation. As a consequence the predicted value of $\theta_{13}$ is within the sensitivity of the experiments which will take data in the near future. The light neutrino spectrum, typical of $A_4$ see-saw models, with its phenomenological implications, also including leptoproduction, is studied in detail.Comment: 20 pages, 2 figure

Phenomenological Tests of Supersymmetric A_4 Family Symmetry Model of Neutrino Mass

Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on $A_4$ symmetry. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from three-fold degeneracy of the neutrino masses at a high energy scale, a viable low energy neutrino mass matrix can indeed be obtained in agreement with constraints on lepton flavour violating $\mu$ and $\tau$ decays. The resulting slepton spectrum must necessarily include at least one mass below 200 GeV which can be produced at the LHC. The predictions for the absolute Majorana neutrino mass scale $m_0 \geq 0.3$ eV ensure that the model will be tested by future cosmological tests and $\beta\beta_{0\nu}$ searches. Rates for lepton flavour violating processes $\ell_j \to \ell_i + \gamma$ in the range of sensitivity of current experiments are typical in the model, with BR(\mu \to e \gamma) \gsim 10^{-15} and the lower bound BR$(\tau \to \mu \gamma) > 10^{-9}$. To first approximation, the model leads to maximal leptonic CP violation in neutrino oscillations.Comment: 23 pages, 7 figure

A See-Saw S4S_4 model for fermion masses and mixings

We present a supersymmetric see-saw $S_4$ model giving rise to the most general neutrino mass matrix compatible with Tri-Bimaximal mixing. We adopt the $S_4\times Z_5$ flavour symmetry, broken by suitable vacuum expectation values of a small number of flavon fields. We show that the vacuum alignment is a natural solution of the most general superpotential allowed by the flavour symmetry, without introducing any soft breaking terms. In the charged lepton sector, mass hierarchies are controlled by the spontaneous breaking of the flavour symmetry caused by the vevs of one doublet and one triplet flavon fields instead of using the Froggatt-Nielsen U(1) mechanism. The next to leading order corrections to both charged lepton mass matrix and flavon vevs generate corrections to the mixing angles as large as ${\cal O}(\lambda_C^2)$. Applied to the quark sector, the symmetry group $S_4\times Z_5$ can give a leading order $V_{CKM}$ proportional to the identity as well as a matrix with ${\cal O}(1)$ coefficients in the Cabibbo $2\times 2$ submatrix. Higher order corrections produce non vanishing entries in the other $V_{CKM}$ entries which are generically of ${\cal O}(\lambda_C^2)$.Comment: 30 pages, 3 figures, minor changes to match the published versio