R-symmetry, Yukawa textures and anomaly mediated supersymmetry breaking

We explore, in the MSSM context, an extension of the Anomaly Mediated Supersymmetry Breaking solution for the soft scalar masses that is possible if the underlying theory has a gauged R-symmetry. The slepton mass problem characteristic of the scenario is resolved, and a context for the explanation of the fermion mass hierarchy provided.Comment: 12 pages, Plain TeX, Uses Harvmac (big). More references added, and improved discussion of FCNC

The Fayet-Iliopoulos D-term and its renormalisation in the MSSM

We consider the renormalisation of the Fayet-Iliopoulos D-term in a softly-broken supersymmetric gauge theory with a non-simple gauge group containing an abelian factor, and present the associated beta-function through three loops. We also include in an appendix the result for several abelian factors. We specialise to the case of the minimal supersymmetric standard model (MSSM), and investigate the behaviour of the Fayet-Iliopoulos coupling for various boundary conditions at the unification scale. We focus particularly on the case of non-standard soft supersymmetry breaking couplings, for which the Fayet-Iliopoulos coupling evolves significantly between the unification scale and the weak scale.Comment: 18 pages, Revtex, 2 figures. Expanded version including general results for gauge groups with several abelian factors. Minor typos correcte

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

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

RG-invariant Sum Rule in a Generalization of Anomaly Mediated SUSY Breaking Models

We study a generalization of anomaly-mediated supersymmetry breaking (AMSB) scenarios, under the assumption that the effects of the high-scale theory do not completely decouple and D-term type contributions can be therefore present. We investigate the effect of such possible D-term additional contributions to soft scalar masses by requiring that, for non-vanishing, renormalizable Yukawa couplings $Y^{ijk}$, the sum of squared soft supersymmetry breaking mass parameters, $M^2_{ijk} \equiv m_i^2+m_j^2+m_k^2$, is RG-invariant, in the sense that it becomes independent of the specific ultraviolet boundary conditions as it occurs in the AMSB models. These type of models can avoid the problem of tachyonic solutions for the slepton mass spectrum present in AMSB scenarios. We implement the electroweak symmetry breaking condition and explore the sparticle spectrum associated with this framework. To show the possible diversity of the sparticle spectrum, we consider two examples, one in which the D-terms induce a common soft supersymmetry breaking mass term for all sfermion masses, and another one in which a light stop can be present in the spectrum.Comment: 24 pages, latex, 12 figure

Fayet-Iliopoulos D-terms, neutrino masses and anomaly mediated supersymmetry breaking

We explore, in the context of the MSSM generalised to admit massive neutrinos, an extension of the Anomaly Mediated Supersymmetry Breaking solution for the soft scalar masses to incorporate Fayet-Iliopoulos D-terms. The slepton mass problem characteristic of the scenario is resolved, and the fermion mass hierarchy is explained via the Froggatt-Nielsen mechanism. FCNC problems are evaded by a combination of universal doublet charges and Yukawa textures which are diagonalised by transforming the left-handed fields only.Comment: 13 pages, TeX, Uses Harvmac (big). Improved R-parity discussion (v2). Redundant singlet excised (v3). Figure added and minor corrections, added references (v4

Optimisation of surface topography characterisation for metal additive manufacturing using coherence scanning interferometry

The surface topography of metal additive manufactured (AM) parts can be challenging to measure due to the presence of complex features, such as high slopes, step like recesses and protuberances, and local variations in reflectance. Recent innovations in coherence scanning interferometry (CSI) technology, such as high dynamic range of exposure and adjustable data acquisition rates for noise reduction, have augmented the baseline sensitivity of a measurement. This enhanced sensitivity expands the capability of CSI instruments to measure surface textures with high slopes or low reflectance, making CSI a potentially valuable tool for process development and quality control of metal AM. This study presents an empirical sensitivity analysis of a CSI system for the top and side surfaces of metal AM parts made from different materials (Ti-6Al-4V and Al-Si-10Mg) and processes (laser powder bed fusion (LPBF) and electron beam powder bed fusion (EBPBF)). The aim of this work is to demonstrate the feasibility of using CSI for characterisation of metal AM surfaces, and to evaluate the effectiveness of relevant CSI measurement settings. Topographic measurements are described through the use of ISO 25178-2 areal surface texture parameters Sq and Sdq and are analysed for data coverage, measurement time and area. The results show that the CSI technique can provide surface topography measurements for metal AM surfaces with a wide range of surface features. Finally, recommendations for optimisation of future measurements on metal AM surfaces using CSI are provided

Anisotropic magnetoresistance in the organic superconductor β″–(BEDT-TTF)2SF5CH2CF2SO3

In this paper, we report transport measurements of interlayer magnetoresistance with field parallel and perpendicular to the current direction in an all organic superconductor β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃. For H∥I, the isothermal magnetoresistance R(H) at low temperatures (

Anomalous low-temperature and high-field magnetoresistance in the organic superconductor β″-(BEDT-TTF)2SF5CH2CF2SO3

We report direct observations of anomalous magnetic-field and temperature dependences of the Shubnikov–de Haas oscillations in the organic superconductor β″-(BEDT-TTF)₂SF₅CH₂CF₂SO₃. Unlike other BEDT-TTF based organic superconductors, a nonmetallic temperature dependence of the background magnetoresistance is clearly observed. It is speculated that the nonmetallic behavior may arise from a partial nesting of the open orbits, similar to the field-induced density wave in the quasi-one-dimensional systems or a charge localization. The analysis of the magnetoresistance oscillations are found to deviate from the conventional Lifshitz-Kosevich description at high field and low temperatures. [S0163-1829(99)05433-8

Signals of anomaly mediated supersymmetry breaking in an e^- gamma collider

We study the signatures of minimal anomaly mediated supersymmetry breaking in an e^- gamma collider. We demonstrate that the associated production of a sneutrino with the lightest chargino leads to a substantially large signal size. The background is negligibly small, though. Even more interestingly, a measurement of the fundamental supersymmetry breaking parameters could be possible.Comment: 25 pages, LaTex, 7 PS figures and 1 table (included