572 research outputs found

    Six-dimensional superconformal couplings of non-abelian tensor and hypermultiplets

    Get PDF
    We construct six-dimensional superconformal models with non-abelian tensor and hypermultiplets. They describe the field content of (2,0) theories, coupled to (1,0) vector multiplets. The latter are part of the non-abelian gauge structure that also includes non-dynamical three- and four-forms. The hypermultiplets are described by gauged nonlinear sigma models with a hyper-Kaehler cone target space. We also address the question of constraints in these models and show that their resolution requires the inclusion of abelian factors. These provide couplings that were previously considered for anomaly cancellations with abelian tensor multiplets and resulted in the selection of ADE gauge groups.Comment: 25 page

    New developments in the quantization of supersymmetric solitons (kinks, vortices and monopoles)

    Get PDF
    We discuss the one-loop quantum corrections to the mass M and central charge Z of supersymmetric solitons: the kink, the vortex and the monopole. Contrary to previous expectations and published results, in each of these cases there are nonvanishing quantum corrections to the mass. For the N=1 kink and the N=2 monopole a new anomaly in Z rescues BPS saturation (M=Z); for the N=2 vortex, BPS saturation is rescued for two reasons: (i) the quantum fluctuations of the Higgs field acquire a nontrivial phase due to the winding of the classical solution, and (ii) a fermionic zero mode used in the literature is shown not to be normalizable.Comment: 15 pages, REVTEX4 style, 1 embedded postscript figure. Extended writeup of a talk given by P. van Nieuwenhuizen at the XXIV Brazilian National Meeting on Particles and Fields (Caxambu, Brazil, 30 Sep - 4 Oct 2003); to appear in the Brazilian Journal of Physic

    Early Indicators of Later Work Levels, Disease, and Death

    Get PDF
    This paper summarizes a collaborative project designed to create a public-use tape suitable for a prospective study of aging among a random sample of 39,616 men mustered into 331 companies of the Union Army. The aim of the project is to measure the effect of socioeconomics and biomedical factors during childhood and early adulthood on the development of specific chronic disease at middle and late ages, on labor force participation at these later ages, and on elapsed time to death. This paper surveys the nature of and quality of the data and data sources to be included in the study, discusses the characteristics of a subsample of recruits from 20 companies recently recruited, looks at questions of representativeness of Union Army recruits to the Northern white male population, and finally examines several issues involving questions of possible selection bias due to linkage failure.

    Disparity among low first ionization potential elements

    Full text link
    The elemental composition of the solar wind differs from the solar photospheric composition. Elements with low first ionization potential (FIP) appear enhanced compared to O in the solar wind relative to the respective photospheric abundances. This so-called FIP effect is different in the slow solar wind and the coronal hole wind. However, under the same plasma conditions, for elements with similar FIPs such as Mg, Si, and Fe, comparable enhancements are expected. We scrutinize the assumption that the FIP effect is always similar for different low FIP elements, namely Mg, Si, and Fe. We investigate the dependency of the FIP effect of low FIP elements on the O7+/O6+ charge state ratio depending on time and solar wind type. We order the observed FIP ratios with respect to the O7+/O6+ charge state ratio into bins and analyze separately the respective distributions of the FIP ratio of Mg, Si, and Fe for each O7+/O6+ charge state ratio bin. We observe that the FIP effect shows the same qualitative yearly behavior for Mg and Si, while Fe shows significant differences during the solar activity maximum and its declining phase. In each year, the FIP effect for Mg and Si always increases with increasing O7+/O6+ charge state ratio, but for high O7+/O6+ charge state ratios the FIP effect for Fe shows a qualitatively different behavior. During the years 2001-2006, instead of increasing with the O7+/O6+ charge state ratio, the Fe FIP ratio exhibits a broad peak. Also, the FIP distribution per O7+/O6+ charge state bin is significantly broader for Fe than for Mg and Si. These observations support the conclusion that the elemental fractionation is only partly determined by FIP. In particular, the qualitative difference behavior with increasing O7+/O6+ charge state ratio between Fe on the one hand and Mg and Si on the other hand is not yet well explained by models of fractionation

    N=6 Superspace Constraints, SUSY Enhancement and Monopole Operators

    Get PDF
    International audienceWe present a systematic analysis of the N=6 superspace constraints in three space-time dimensions. The general coupling between vector and scalar supermultiplets is encoded in an SU(4) tensor WjiW^i_j which is a function of the matter fields and subject to a set of algebraic and super-differential relations. We give a genuine N=6 classification for superconformal models with polynomial interactions and find the known ABJM and ABJ models. We further study the issue of supersymmetry enhancement to N=8 and the role of monopole operators in this scenario. To this end we assume the existence of a composite monopole operator superfield which we use to formulate the additional supersymmetries as internal symmetries of the N=6 superspace constraints. From the invariance conditions of these constraints we derive a system of superspace constraints for the proposed monopole operator superfield. This constraint system defines the composite monopole operator superfield analogously to the original N=6 superspace constraints defining the dynamics of the elementary fields

    Quantum corrections to mass and central charge of supersymmetric solitons

    Full text link
    We review some recent developments in the subject of quantum corrections to soliton mass and central charge. We consider in particular approaches which use local densities for these corrections, as first discussed by Hidenaga Yamagishi. We then consider dimensional regularization of the supersymmetric kink in 1+1 dimensions and an extension of this method to a 2+1-dimensional gauge theory with supersymmetric abelian Higgs vortices as the solitons.Comment: 41 pages. Contribution to the Hidenaga Yamagishi commemorative volume of Physics Reports, edited by E. Witten and I. Zahe

    FDG PET in Thyroid Cancer

    Get PDF
    Thyroid malignancies are relatively rare cancer types but have a substantially high incidence in the group of all endocrine malignancies. Most thyroid cancer patients have differentiated thyroid cancer and prognosis is generally favourable. Tumour growth tends to be slow and radioiodine therapy is successful in differentiated cell tumour type with the ability to accumulate iodine. So, where can 18F-fluorodeoxyglucose positron emission tomography (FDG PET) imaging be applied? The role of FDG PET in differentiated thyroid cancer starts with the development of metastatic diseases, which are not responsive to radioiodine therapy anymore. FDG accumulates in tumour lesions that are missed by iodine scintigraphy. FDG PET is more sensitive in patients with an aggressive histological subtype, including HĂĽrthle cell. Thyroid cancer is definitely not the role model indication for FDG PET imaging, but for the management of differentiated thyroid cancer with metastases and more aggressive types of malignancies of the thyroid, FDG PET proves to be clinically useful. Incidental detection of malignancy in FDG-avid thyroid nodules has to be taken into consideration when FDG PET examinations have been conducted for reasons unrelated to the thyroid

    Evolution of an equatorial coronal hole structure and the released coronal hole wind stream: Carrington rotations 2039 to 2050

    Full text link
    The Sun is a highly dynamic environment that exhibits dynamic behavior on many different timescales. In particular, coronal holes exhibit temporal and spatial variability. Signatures of these coronal dynamics are inherited by the coronal hole wind streams that originate in these regions and can effect the Earth's magnetosphere. Both the cause of the observed variabilities and how these translate to fluctuations in the in situ observed solar wind is not yet fully understood. During solar activity minimum the structure of the magnetic field typically remains stable over several Carrington rotations (CRs). But how stable is the solar magnetic field? Here, we address this question by analyzing the evolution of a coronal hole structure and the corresponding coronal hole wind stream emitted from this source region over 12 consecutive CRs in 2006. To this end, we link in situ observations of Solar Wind Ion Composition Spectrometer (SWICS) onboard the Advanced Composition Explorer (ACE) with synoptic maps of Michelson Doppler imager (MDI) on the Solar and Heliospheric Observatory (SOHO) at the photospheric level through a combination of ballistic back-mapping and a potential field source surface (PFSS) approach. Together, these track the evolution of the open field line region that is identified as the source region of a recurring coronal hole wind stream. We find that the shape of the open field line region and to some extent also the solar wind properties are influenced by surrounding more dynamic closed loop regions. We show that the freeze-in order can change within a coronal hole wind stream on small timescales and illustrate a mechanism that can cause changes in the freeze-in order. The inferred minimal temperature profile is variable even within coronal hole wind and is in particular most variable in the outer corona
    • …
    corecore