70 research outputs found

    Energy Independent Solution to the Solar Neutrino Anomaly including the SNO data

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    The global data on solar neutrino rates and spectrum, including the SNO charged current rate, can be explained by LMA, LOW or the energy independent solution -- corresponding to near-maximal mixing. All the three favour a mild upward renormalisation of the Cl rate. A mild downward shift of the BB neutrino flux is favoured by the energy independent and to a lesser extent the LOW solution, but not by LMA. Comparison with the ratio of SK elastic and SNO charged current scattering rates favours the LMA over the other two solutions, but by no more than 1.5σ1.5\sigma.Comment: 18 pages, latex, 3 figure

    Flavour and Collider Interplay for SUSY at LHC7

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    The current 7 TeV run of the LHC experiment shall be able to probe gluino and squark masses up to values larger than 1 TeV. Assuming that hints for SUSY are found in the jets plus missing energy channel by the end of a 5 fb1^{-1} run, we explore the flavour constraints on three models with a CMSSM-like spectrum: the CMSSM itself, a Seesaw extension of the CMSSM, and Flavoured CMSSM. In particular, we focus on decays that might have been measured by the time the run is concluded, such as BsμμB_s\to\mu\mu and μeγ\mu\to e\gamma. We also analyse constraints imposed by neutral meson bounds and electric dipole moments. The interplay between collider and flavour experiments is explored through the use of three benchmark scenarios, finding the flavour feedback useful in order to determine the model parameters and to test the consistency of the different models.Comment: 44 pages, 15 figures; v3: minor corrections, added references, updated figures. Version accepted for publicatio

    A New Parametrization of the Seesaw Mechanism and Applications in Supersymmetric Models

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    We present a new parametrization of the minimal seesaw model, expressing the heavy-singlet neutrino Dirac Yukawa couplings (Yν)ij(Y_\nu)_{ij} and Majorana masses MNiM_{N_i} in terms of effective light-neutrino observables and an auxiliary Hermitian matrix H.H. In the minimal supersymmetric version of the seesaw model, the latter can be related directly to other low-energy observables, including processes that violate charged lepton flavour and CP. This parametrization enables one to respect the stringent constraints on muon-number violation while studying the possible ranges for other observables by scanning over the allowed parameter space of the model. Conversely, if any of the lepton-flavour-violating process is observed, this measurement can be used directly to constrain (Yν)ij(Y_\nu)_{ij} and MNi.M_{N_i}. As applications, we study flavour-violating τ\tau decays and the electric dipole moments of leptons in the minimal supersymmetric seesaw model.Comment: Important references adde

    1D Frustrated Ferromagnetic Model with Added Dzyaloshinskii-Moriya Interaction

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    The one-dimensional (1D) isotropic frustrated ferromagnetic spin-1/2 model is considered. Classical and quantum effects of adding a Dzyaloshinskii-Moriya (DM) interaction on the ground state of the system is studied using the analytical cluster method and numerical Lanczos technique. Cluster method results, show that the classical ground state magnetic phase diagram consists of only one single phase: "chiral". The quantum corrections are determined by means of the Lanczos method and a rich quantum phase diagram including the gapless Luttinger liquid, the gapped chiral and dimer orders is obtained. Moreover, next nearest neighbors will be entangled by increasing DM interaction and for open chains, end-spins are entangled which shows the long distance entanglement (LDE) feature that can be controlled by DM interaction.Comment: 8 pages, 9 figure

    Gravitationally violated U(1) symmetry and neutrino anomalies

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    The current searches for neutrino oscillations seem to suggest an approximate L_e-L_\m-L_{\tau} flavor symmetry. This symmetry implies a pair of degenerate neutrinos with mass m0m_0 and large leptonic mixing. We explore the possibility that gravitational interactions break this global symmetry. The Planck scale suppressed breaking of the L_e-L_\m-L_{\tau} symmetry is shown to lead to the right amount of splitting among the degenerate neutrinos needed in order to solve the solar neutrino problem. The common mass m0m_0 of the pair can be identified with the atmospheric neutrino scale. A concrete model is proposed in which smallness of m0m_0 and hierarchy in the solar and atmospheric neutrino scales get linked to hierarchies in the weak, grand unification and the Planck scales.Comment: 12 pages, LATE

    Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

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    Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning

    Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980�2015: a systematic analysis for the Global Burden of Disease Study 2015

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    Background Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures. Methods We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14�294 geography�year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Findings Globally, life expectancy from birth increased from 61·7 years (95 uncertainty interval 61·4�61·9) in 1980 to 71·8 years (71·5�72·2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11·3 years (3·7�17·4), to 62·6 years (56·5�70·2). Total deaths increased by 4·1 (2·6�5·6) from 2005 to 2015, rising to 55·8 million (54·9 million to 56·6 million) in 2015, but age-standardised death rates fell by 17·0 (15·8�18·1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14·1 (12·6�16·0) to 39·8 million (39·2 million to 40·5 million) in 2015, whereas age-standardised rates decreased by 13·1 (11·9�14·3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42·1, 39·1�44·6), malaria (43·1, 34·7�51·8), neonatal preterm birth complications (29·8, 24·8�34·9), and maternal disorders (29·1, 19·3�37·1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146�000 deaths, 118�000�183�000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393�000 deaths, 228�000�532�000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost YLLs) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death. Interpretation At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems. Funding Bill & Melinda Gates Foundation. © 2016 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY licens

    The Physics of the B Factories

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