An Improved Analysis of b→sγb\to s\gamma in Supersymmetry

An improved analysis of the $b\to s+\gamma$ decay in the minimal flavor violating case is given taking into account additional contributions in the supersymmetric sector which enter in the next-to-leading-order (NLO) and are enhanced by $\tan\beta$ factors. Specifically, we compute a set of twenty one-loop diagrams to give the most complete analysis to date of the NLO supersymmetric corrections. These modifications are computed from the effective charged Higgs and neutral Higgs couplings involving twelve loop diagrams for the charged Higgs sector and eight loop diagrams for the neutral Higgs sector. While the computations of these corrections are available in the literature, their full forms including the complex phase dependence has not be considered. Our analysis takes account of the full allowed set of twenty one-loop diagrams and is more general since it also includes the full dependence on CP phases in non universal sugra and MSSM models. A numerical analysis is carried out to estimate the size of the corrections to $b\to s+\gamma$. We also briefly discuss the implications of these results for the search for supersymmetry.Comment: 46 pages, 11 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

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

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

Status of the CPT Violating Interpretations of the LSND Signal

We study the status of the CPT violating neutrino mass spectrum which has been proposed to simultaneously accommodate the oscillation data from LSND, KamLAND, atmospheric and solar neutrino experiments, as well as the non-observation of anti-neutrino disappearance in short-baseline reactor experiments. We perform a three-generation analysis of the global data with the aim of elucidating the viability of this solution. We find no compatibility between the results of the oscillation analysis of LSND and all-but-LSND data sets below 3$\sigma$ CL. Furthermore, the global data without LSND show no evidence for CPT violation: the best fit point of the all-but-LSND analysis occurs very close to a CPT conserving scenario.Comment: Improved version, to appear in Phys. Rev. D, 16 pages, 5 figure

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

Is comorbidity in adolescence a predictor for adult low back pain? A prospective study of a young population

BACKGROUND: It has previously been shown that low back pain (LBP) often presents already in the teenage years and that previous LBP predicts future LBP. It is also well documented that there is a large degree of comorbidity associated with LBP, both in adolescents and adults. The objective of this study is to gain a deeper insight into the etiology of low back pain and to possibly develop a tool for early identification of high-risk groups. This is done by investigating whether different types of morbidity in adolescence are associated with LBP in adulthood. METHODS: Almost 10,000 Danish twins born between 1972 and 1982 were surveyed by means of postal questionnaires in 1994 and again in 2002. The questionnaires dealt with various aspects of general health, including the prevalence of LBP, classified according to number of days affected during the previous year (0, 1–7, 8–30, >30). The predictor variables used in this study were LBP, headache, asthma and atopic disease at baseline; the outcome variable was persistent LBP (>30 days during the past year) at follow-up. Associations between morbidity in 1994 and LBP in 2002 were investigated. RESULTS: LBP, headache and asthma in adolescence were positively associated with future LBP. There was no association between atopic disease and future LBP. Individuals with persistent LBP at baseline had an odds ratio of 3.5 (2.8–4.5) for future LBP, while the odds ratio for those with persistent LBP, persistent headache and asthma was 4.5 (2.5–8.1). There was a large degree of clustering of these disorders, but atopic disease was not part of this pattern. CONCLUSION: Young people from 12 to 22 years of age with persistent LBP during the previous year have an odds ratio of 3.5 persistent LBP eight years later. Both headache and asthma are also positively associated with future LBP and there is a large clustering of LBP, headache and asthma in adolescence