595 research outputs found

    Consistency of the Two Higgs Doublet Model and CP violation in top production at the LHC

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    It is important to provide guidance on whether CP violation may be measurable in top-quark production at the Large Hadron Collider. The present work extends an earlier analysis of the non-supersymmetric Two-Higgs-Doublet Model in this respect, by allowing a more general potential. Also, a more comprehensive study of theoretical and experimental constraints on the model is presented. Vacuum stability, unitarity, direct searches and electroweak precision measurements severely constrain the model. We explore, at low \tan\beta, the allowed regions in the multidimensional parameter space that give a viable physical model. This exploration is focused on the parameter space of the neutral sector rotation matrix, which is closely related to the Yukawa couplings of interest. In most of the remaining allowed regions, the model violates CP. We present a quantitative discussion of a particular CP-violating observable. This would be measurable in semileptonically decaying top and antitop quarks produced at the LHC, provided the number of available events is of the order of a million.Comment: 45 pages, 10 figures, some in (essential) colour. Figures 2, 6 and 7 are bitmapped, better quality available on request. Version to appear in Nucl. Phys.

    Elementi nastali raspadom iz prirodnih radioaktivnih nizova u pitkoj vodi i cigaretama u Iranu

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    The uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.Uranijev (238U) radioaktivni niz obuhvaća najvažnije izotope radija (226Ra), radona (222Rn) i polonija (210Po), a poluvijek raspada im je 1600 godina za prvi element, 3,8 dana za drugi te 140 dana za treći. Premda je radijeva kemijska struktura vrlo slična kalcijevoj, rukovanje njime u laboratoriju i prirodnome okolišu otežano je činjenicom da proizvodi radioaktivni plin radon. S pomoću prosječnih koncentracija prirodnoga radionuklida 226Ra u pitkoj vodi izračunali smo njegovu godišnju efektivnu dozu u različitim dijelovima Irana. U drugome smo istraživanju izmjerili koncentracije 210Po u iranskim cigaretama i izračunali njegov unos i koncentracije u plućnome tkivu. Naši rezultati upućuju na to da je prosječna koncentracija 226Ra u pitkoj vodi niža od 100 mBq L-1 koju preporučuje Svjetska zdravstvena organizacija, dok je prosječna koncentracija 210Po i 210Pb u iranskim cigaretama relativno visoka u odnosu na druge cigarete dostupne na tržištu

    Constraining the Two-Higgs-Doublet-Model parameter space

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    We confront the Two-Higgs-Doublet Model with a variety of experimental constraints as well as theoretical consistency conditions. The most constraining data are the \bar B\to X_s\gamma decay rate (at low values of M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b) (both of which restrict the model at low values of \tan\beta), and the B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs boson is considered, as well as the muon anomalous magnetic moment. Since perturbative unitarity excludes high values of \tan\beta, the model turns out to be very constrained. We outline the remaining allowed regions in the \tan\beta-M_{H^\pm} plane for different values of the masses of the two lightest neutral Higgs bosons, and describe some of their properties.Comment: 17 pages, 17 figure

    Human demography changes in Morocco and environmental imprint during the Holocene

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    The aim of this work is to reconstruct the periods of growth and decline of human populations in Morocco and their potential impacts on the landscape over the past 10,000 years. In order to estimate the trends in the human population size between 10,000 and 3000 years ago, we used a summed probability distribution (SPD) of radiocarbon dates from a wide range of archaeological sites throughout Morocco. Landscape changes were identified and quantified from a dataset of fossil pollen records. Different anthropogenic pollen markers, as well as natural vegetation groups and taxonomic richness were used to analyse the relationship between long-term trends in human population expansion or regression and type of impact on the landscape. The sub-regions of Morocco have different topographies and climates, which have either favoured or prevented the establishment and/or spread of human populations. In order to identify the areas most significantly impacted by humans and the timing of such impacts, we have reconstructed and compared the same past anthropogenic and landscape proxies along with the population trends within the lowlands and mountainous areas. The lowlands were more strongly impacted earlier in the Holocene than the mountainous areas. Anthropogenic markers indicate that farming expanded in the lowlands during the first major expansion of human populations between ca. 7200 and 6700 cal. yr BP at the start of the Neolithic period. In the Atlas and Rif Mountains, anthropogenic impact is not clearly detectable in any of these areas before 4000 cal. BP. </jats:p

    CP-odd invariants in models with several Higgs doublets

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    We present CP-odd Higgs-basis invariants, which can be used to signal CP violation in a multi-Higgs system, written in an arbitrary Higgs basis. It is shown through specific examples how these CP-odd invariants can also be useful to determine the character of CP breaking (i.e. whether it is hard or soft CP breaking) in a given Higgs Lagrangian. We analyse in detail the cases of two and three Higgs doublets

    In silico identification of potential chaperone genes that belong to type III and type IV secretion systems in Xanthomonas axonopodis pv citri

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    The secretion of bacterial virulence factors and flagellar components requires the assistance of specific type III and flagellar chaperones. Standard computational annotation of the genome of Xanthomonas axonopodis pv citri, a plant pathogen that causes citrus canker, initially did not identify any genes belonging to these chaperone categories since the primary sequence homology between them was very low. However, in a search for hypothetical proteins with characteristics similar to these chaperones, we have now identified 30 chromosomal and 10 plasmidial potential genes encoding chaperones belonging to types III/IV, and flagellar secretion systems in this organism. The significance of these findings is discussed.28232132

    Autoimmune Diseases of the GI Tract Part II: Emergence of Diagnostic Tools and Treatments

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    Autoimmune diseases (AD) have emerged as a pandemic in our modern societies, especially after the World War II. In part I, we have reviewed five main diseases and shed light on different aspects from introducing the concept of autoimmunity, the description of the disease’s pathogenesis and the diagnosis, the role of antibodies as markers for the prediction of the disease, the link between the gut and brain through what is known as the gut–brain axis, and the relationship of this axis in GI autoimmune diseases. In this chapter, we review the role of antibodies as markers for the prediction of the disease, artificial intelligence in GI autoimmune diseases, the nutritional role and implications in the five GI autoimmune diseases, and finally the treatment of those diseases

    Neuronal circuitry for pain processing in the dorsal horn

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    Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region

    Electroweak Symmetry Breaking at the LHC

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    One of the major goals of the Large Hadron Collider is to probe the electroweak symmetry breaking mechanism and the generation of the masses of the elementary particles. We review the physics of the Higgs sector in the Standard Model and some of its extensions such as supersymmetric theories and models of extra dimensions. The prospects for discovering the Higgs particles at the LHC and the study of their fundamental properties are summarised.Comment: 27 pages, 45 figures, uses LaTeX (insa.sty). Invited review for volume on LHC physics to celebrate the Platinum Jubilee of the Indian National Science Academy, edited by Amitava Datta, Biswarup Mukhopadhyaya and Amitava Raychaudhuri. Expanded the acronym in the title in the annoncement. No other change in the text or reference
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