197 research outputs found

    Threshold and Flavour Effects in the Renormalization Group Equations of the MSSM II: Dimensionful couplings

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    We re-examine the one-loop renormalization group equations (RGEs) for the dimensionful parameters of the minimal supersymmetric Standard Model with broken supersymmetry, allowing for arbitrary flavour structure of the soft SUSY breaking (SSB) parameters. We include threshold effects by evaluating the β\beta-functions in a sequence of (non-supersymmetric) effective theories with heavy particles decoupled at the scale of their mass. We present the most general form for high scale SSB parameters that obtains if we assume that the supersymmetry breaking mechanism does not introduce new inter-generational couplings. This form, possibly amended to allow additional sources of flavour-violation, serves as a boundary condition for solving the RGEs for the dimensionful MSSM parameters. We then present illustrative examples of numerical solutions to the RGEs. We find that in a SUSY GUT with the scale of SUSY scalars split from that of gauginos and higgsinos, the gaugino mass unification condition may be violated by O{\cal O}(10%). As another illustration, we show that in mSUGRA, the rate for the flavour-violating t~1cZ~1\tilde{t}_1\to c\tilde{Z}_1 decay obtained using the complete RGE solution is smaller than that obtained using the commonly-used "single-step" integration of the RGEs by a factor 10-25, and so may qualitatively change expectations for topologies from top-squark pair production at colliders. Together with the RGEs for dimensionless couplings presented in a companion paper, the RGEs in Appendix B of this paper form a complete set of one-loop MSSM RGEs that include threshold and flavour-effects necessary for two-loop accuracy.Comment: 96 pages, 14 figures, revtex4, multirow.sty, bm.sty, amsmath.sty; Corrected Fig. 3 and Eqs. (B9), (B11), (B13) - (B20) and (B24). Results change by less than 1

    Renormalisation Group Analysis of Supersymmetric Particle Interactions

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    In the Minimal Supersymmetric Standard Model (MSSM), there are numerous sources of flavour-violation in addition to the usual Kobayashi-Maskawa mixing matrix of the Standard Model. We reexamine the renormalisation group equations (RGEs) with a view to investigating flavour effects in a supersymmetric theory with an arbitrary flavour structure at some high scale. To incorporate (two-loop sized) threshold effects in the one-loop RGEs, we calculate the beta-functions using a sequence of (non-supersymmetric) effective theories with heavy particles decoupled at the scale of their mass, keeping track of the fact that many couplings (such as gauge and gaugino couplings) which are equal in an exact supersymmetric theory may no longer be equal once the supersymmetry (SUSY) is broken. We find that this splitting, which is ignored in the literature, may be larger than two-loop terms that are included. In addition, gaugino couplings develop flavour structure that is absent without including decoupling effects. A program (to be incorporated into ISAJET) has been developed, which includes flavour-violating couplings of superparticles and solves the two-loop threshold RGEs subject to specified high scale inputs. The weak scale flavour structure derived in this way can be applied to the study of flavour-changing decays of SUSY particles. As an illustration, we revisit the branching ratio of the flavour-violating decay of the top squark. We find that, in the minimal supergravity (mSUGRA) class of models, previous estimates for the width of this decay have been too large by a factor 10-25. We also analyse the consequences of introducing non-universality in the high scale soft SUSY-breaking mass matrices and find that under these conditions the partial width can be altered by a large amount.Comment: PhD Dissertation, approx. 212 pages, 22 figures, 5 table

    The Association of Coloproctology of Great Britain and Ireland consensus guidelines in emergency colorectal surgery

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    ACKNOWLEDGEMENTS Review and editing: S.R. Brown, Professor of Surgery, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK. Email [email protected]. Patient summary: R.G. Arnott, Retired Professor, Patient Liaison Group, Association of Coloproctology of Great Britain and Ireland, Royal College of Surgeons of England, London, UK. Email [email protected]. Delphi review: C.P. Macklin. BMedSci BM BS FRCS DM, Consultant Colorectal Surgeon, Mid Yorkshire Hospitals, UK. Email [email protected] reviewedPublisher PD

    The screen test 1915–1930:how stars were born

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    This article examines the emergence of the screen test as a cultural phenomenon during the silent era in the US and Europe and its role in the development of the star system. The lore that grew up around the screen test almost from its inception held out the possibility for members of the public to cross a threshold into the rarefied world of celebrity. The screen test itself is situated in the liminal space not only between audience and actor, but also between fiction and non-fiction, Europe and Hollywood, the silent era and the talkies, and the public and private spheres. In order to trace the ways in which the screen test as such was narrativized and conceptualized in its foundational stages, this article will analyse accounts from Hollywood and European fan magazines of the silent era, including articles, short fiction, and early cinema apocrypha. The article culminates in a discussion of the film Prix de Beauté / Beauty Prize (Augusto Genina, 1930), which starred Louise Brooks, herself a transnational film icon whose film career spanned the divide between Hollywood and Europe. The film’s final scene, in which a beauty queen is shot dead by her jealous husband as she watches a screen test of herself, has been invoked by a number of film scholars as an allegory of the work performed by cinema, which preserves and disseminates the image of the star far beyond the actor’s physical presence. Speaking to historical conditions of star-making while also capturing its resonance in cultural mythology, the conclusion of Prix de Beauté allows us to consider the origins and functions of screen test discourse itself

    Manipulation and Deposition of Complex, Functional Block Copolymer Nanostructures using Optical Tweezers

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    Block copolymer self-assembly has enabled the creation of a range of solution-phase nanostructures with applications from optoelectronics and biomedicine to catalysis. However, to incorporate such materials into devices a method that facilitates their precise manipulation and deposition is desirable. Herein we describe how optical tweezers can be used to trap, manipulate, and pattern individual cylindrical micelles and larger hybrid micellar materials. Through the combination of TIRF imaging and optical trapping we can precisely control the three-dimensional motion of individual cylindrical block copolymer micelles in solution, enabling the creation of customizable arrays. We also demonstrate that dynamic holographic assembly enables the creation of ordered customizable arrays of complex hybrid block copolymer structures. By creating a program which automatically identifies, traps, and then deposits multiple assemblies simultaneously we have been able to dramatically speed up this normally slow process, enabling the fabrication of arrays of hybrid structures containing hundreds of assemblies in minutes rather than hours

    Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets

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    We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
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