4,001 research outputs found

    Gauge singlet renormalisation in softly-broken supersymmetric theories

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    We consider the renormalisation of a softly-broken supersymmetric theory with singlet fields and a superpotential with a linear term. We show that there exist exact beta-functions for both the linear term in the superpotential and the associated linear term in the Lagrangian. We also construct exact renormalisation group invariant trajectories for these terms, corresponding to the conformal anomaly solution for the soft masses and couplings.Comment: 13 pages, Plain TeX, uses Harvmac. Typos corrected and minor clarification adde

    Dimensional Reduction in Non-Supersymmetric Theories

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    It is shown that regularisation by dimensional reduction is a viable alternative to dimensional regularisation in non-supersymmetric theories.Comment: 13 pages, phyzzx, LTH 32

    Anomaly Mediation, Fayet-Iliopoulos D-terms and precision sparticle spectra

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    We consider the sparticle spectra that arise when anomaly mediation is the source of supersymmetry-breaking and the tachyonic slepton problem is solved by a Fayet-Iliopoulos D-term. We also show how this can lead to a minimal viable extension of anomaly mediation, in which the gauge symmetry associated with this D-term is broken at very high energies, leaving as its footprint in the low energy theory only the required D-terms and seesaw neutrino masses.Comment: 20 pages, 5 figures. Uses epsf. Minor corrections and added referenc

    The Fayet-Iliopoulos D-term and its renormalisation in softly-broken supersymmetric theories

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    We consider the renormalisation of the Fayet-Iliopoulos D-term in a softly-broken abelian supersymmetric theory, and calculate the associated beta-function through three loops. We show that there exists (at least through three loops) a renormalisation group invariant trajectory for the coefficient of the D-term, corresponding to the conformal anomaly solution for the soft masses and couplings.Comment: 30 pages, Revtex, 15 Figures. Minor changes, and inadvertent omission of author from this abstract correcte

    Association between musculoskeletal pain with social isolation and loneliness: analysis of the English Longitudinal Study of Ageing

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    Introduction: Musculoskeletal pain is a prevalent health challenge for all age groups worldwide, but most notably in older adults. Social isolation is the consequence of a decrease in social network size with a reduction in the number of social contacts. Loneliness is the psychological embodiment of social isolation and represents an individual’s perception of dissatisfaction in the quality or quantity of their social contacts. This study aims to determine whether a relationship exists between musculoskeletal pain and social isolation and loneliness. Methods: A cross-sectional analysis of the English Longitudinal Study of Ageing (ELSA) cohort was undertaken. ELSA is a nationally representative sample of the non-institutionalised population of individuals aged 50 years and over based in England. Data were gathered on social isolation through the ELSA Social Isolation Index, loneliness through the University of California, Los Angeles (UCLA) Loneliness Scale and musculoskeletal pain. Data for covariates included physical activity, depression score, socioeconomic status, access to transport and demographic characteristics. Logistic regression analyses were undertaken to determine the relationship between social isolation and loneliness with pain and the additional covariates. Results: A total of 9299 participants were included in the analysis. This included 4125 (44.4%) males, with a mean age of 65.8 years. There was a significant association where social isolation was lower for those in pain (odd ratio (OR): 0.87; 95% confidence intervals (CI): 0.75 to 0.99), whereas the converse occurred for loneliness where this was higher for those in pain (OR: 1.15; 95% CI: 1.01 to 1.31). Age, occupation, physical activity and depression were all associated with increased social isolation and loneliness. Conclusion: People who experience chronic musculoskeletal pain are at greater risk of being lonely, but at less risk of being socially isolated. Health professionals should consider the wider implications of musculoskeletal pain on individuals, to reduce the risk of negative health implications associated with loneliness from impacting on individual’s health and well-being

    Low-density series expansions for directed percolation I: A new efficient algorithm with applications to the square lattice

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    A new algorithm for the derivation of low-density series for percolation on directed lattices is introduced and applied to the square lattice bond and site problems. Numerical evidence shows that the computational complexity grows exponentially, but with a growth factor \lambda < \protect{\sqrt[8]{2}}, which is much smaller than the growth factor \lambda = \protect{\sqrt[4]{2}} of the previous best algorithm. For bond (site) percolation on the directed square lattice the series has been extended to order 171 (158). Analysis of the series yields sharper estimates of the critical points and exponents.Comment: 20 pages, 8 figures (3 of them > 1Mb

    Chemical NOx budget in the upper troposphere over the tropical South Pacific

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    The chemical NOx budget in the upper troposphere over the tropical South Pacific is analyzed using aircraft measurements made at 6-12 km altitude in September 1996 during the Global Tropospheric Experiment (GTE) Pacific Exploratory Mission (PEM) Tropics A campaign. Chemical loss and production rates of NOx along the aircraft flight tracks are calculated with a photochemical model constrained by observations. Calculations using a standard chemical mechanism show a large missing source for NOx; chemical loss exceeds chemical production by a factor of 2.4 on average. Similar or greater NOx budget imbalances have been reported in analyses of data from previous field studies. Ammonium aerosol concentrations in PEM-Tropics A generally exceeded sulfate on a charge equivalent basis, and relative humidities were low (median 25% relative to ice). This implies that the aerosol could be dry in which case N2O5 hydrolysis would be suppressed as a sink for NOx. Suppression of N2O5 hydrolysis and adoption of new measurements of the reaction rate constants for NO2 + OH + M and HNO3 + OH reduces the median chemical imbalance in the NOx budget for PEM-Tropics A from 2.4 to 1.9. The remaining imbalance cannot be easily explained from known chemistry or long-range transport of primary NOx and may imply a major gap in our understanding of the chemical cycling of NOx in the free troposphere. Copyright 2000 by the American Geophysical Union

    Decoupling of the Ï”\epsilon-scalar mass in softly broken supersymmetry

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    It has been shown recently that the introduction of an unphysical Ï”\epsilon-scalar mass m~\tilde{m} is necessary for the proper renormalization of softly broken supersymmetric theories by dimensional reduction (\drbar). In these theories, both the two-loop ÎČ\beta-functions of the scalar masses and their one-loop finite corrections depend on m~2\tilde{m}^2. We find, however, that the dependence on m~2\tilde{m}^2 can be completely removed by slightly modifying the \drbar renormalization scheme. We also show that previous \drbar calculations of one-loop corrections in supersymmetry which ignored the m~2\tilde{m}^2 contribution correspond to using this modified scheme.Comment: 7 pages, LTH-336, NUB-3094-94TH, KEK-TH-40
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