On the Spontaneous CP Breaking in the Higgs Sector of the Minimal Supersymmetric Standard Model

We revise a recently proposed mechanism for spontaneous CP breaking at finite temperature in the Higgs sector of the Minimal Supersymmetric Standard Model, based on the contribution of squarks, charginos and neutralinos to the one-loop effective potential. We have included plasma effects for all bosons and added the contribution of neutral scalar and charged Higgses. While the former have little effect, the latter provides very strong extra constraints on the parameter space and change drastically the previous results. We find that CP can be spontaneously broken at the critical temperature of the electroweak phase transition without any fine-tuning in the parameter space.Comment: 9 pages, LATEX, 3 appended postscript figures, IEM-FT-76/9

Obesity dependent metabolic signatures associated with nonalcoholic fatty liver disease progression

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (n=90) or diagnosed with NAFLD (steatosis, n=246; NASH, n=131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultra-performance liquid chromatography coupled to mass spectrometry (UPLCMS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual’s level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values = 0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention

Impact of habitat structure on fish populations in kelp forests at a seascape scale

Habitat use by a species is a vital component in explaining the dynamics of natural populations. For mobile marine species such as fishes, describing habitat heterogeneity at a seascape scale is essential because it quantifies the spatial extent to which fishes are interacting with their environment. Here, we explored the relationships between habitat metrics and the density and size of kelp forest fishes across a seascape that is naturally fragmented. Multibeam sonar and GIS analysis were employed to create a seascape map that explicitly defined bathymetry and spatial configuration of rocky reefs in southern California (USA). Georeferenced subtidal transects were conducted across this seascape to describe habitat attributes, including the density of macroalgae, and record the number and size of fishes. Multiple regression analyses were conducted to identify which variables of habitat structure were most important in describing numerical density, biomass density, average size, and maximum size for fishes. Responses to different habitat components were dependent on particular species, choice of spatial scale, and the inherent characteristics of the seascape itself. Notably, the relative influence of seascape components was dependent on the configuration of the seascape, where fishes in a more isolated and less connected seascape were more influenced by spatial configuration than fishes in a seascape with greater habitat connectedness. This study demonstrates that explicit habitat maps allow for a more comprehensive understanding of population structure when describing fishes across large spatial scales

Testing Gluino Spin with Three-Body Decays

We examine the possibility of distinguishing a supersymmetric gluino from a Kaluza-Klein gluon of universal extra dimensions (UED) at the Large Hadron Collider (LHC). We focus on the case when all kinematically allowed tree-level decays of this particle are 3-body decays into two jets and a massive daughter (typically weak gaugino or Kaluza-Klein weak gauge boson). We show that the shapes of the dijet invariant mass distributions differ significantly in the two models, as long as the mass of the decaying particle mA is substantially larger than the mass of the massive daughter mB. We present a simple analysis estimating the number of events needed to distinguish between the two models under idealized conditions. For example, for mA/mB=10, we find the required number of events to be of order several thousand, which should be available at the LHC within a few years. This conclusion is confirmed by a parton level Monte Carlo study which includes the effects of experimental cuts and the combinatoric background.Comment: 19 pages, 10 figure

On Measuring Split-SUSY Neutralino and Chargino Masses at the LHC

In Split-Supersymmetry models, where the only non-Standard Model states produceable at LHC-energies consist of a gluino plus neutralinos and charginos, it is conventionally accepted that only mass differences among these latter are measureable at the LHC. The present work shows that application of a simple `Kinematic Selection' technique allows full reconstruction of neutralino and chargino masses from one event, in principle. A Monte Carlo simulation demonstrates the feasibilty of using this technique at the LHC.Comment: 17 pages, 4 figures; EPJC versio

Identifying coherent patterns of environmental change between multiple, multivariate records: an application to four 1000-year diatom records from Victoria, Australia

Empirical orthogonal functions (EOFs) of indirect archives of environmental change are increasingly used to identify coherent trends between palaeoclimate records, to separate externally forced patterns from locally driven idiosyncrasies. Lake sediments are particularly suited to such syntheses: they are abundant in most landscapes and record a wide array of information, yet local complexities often conceal or confuse the climate signal recorded at individual sites. Lake sediment parameters usually exhibit non-linear, multivariate and indirect responses to climate, therefore identifying coherent patterns between two or more lake records presents a complex challenge. Ideally, the selection of representative variables should be non-subjective and inclusive of as many different variables as possible, allowing for unexpected correlations between sites. In order to meet such demands, we propose a two-tier ordination procedure whereby site-specific (local) ordinations, obtained using Detrended Correspondence Analysis (DCA), are nested within a second, regional EOF. Using the local DCAs as representative variables allows the retention of a larger fraction of variance from each site, removes any subjectivity from variable selection and retains the potential for observing multiple, coherent signals from within and between each dataset. We explore this potential using four decadally resolved diatom records from volcanic lakes in Western Victoria, Australia. The records span the 1000 years prior to European settlement in CE 1803. Our analyses reveal at least two coherent patterns of ecological change that are manifest in each of the four datasets, patterns which may have been overlooked by a single-variable, empirical orthogonal function approach. This intra-site coherency provides a valuable step towards understanding multi-decadal hydroclimate variability in southeastern Australia

Baryogenesis, Electric Dipole Moments and Dark Matter in the MSSM

We study the implications for electroweak baryogenesis (EWB) within the minimal supersymmetric Standard Model (MSSM) of present and future searches for the permanent electric dipole moment (EDM) of the electron, for neutralino dark matter, and for supersymmetric particles at high energy colliders. We show that there exist regions of the MSSM parameter space that are consistent with both present two-loop EDM limits and the relic density and that allow for successful EWB through resonant chargino and neutralino processes at the electroweak phase transition. We also show that under certain conditions the lightest neutralino may be simultaneously responsible for both the baryon asymmetry and relic density. We give present constraints on chargino/neutralino-induced EWB implied by the flux of energetic neutrinos from the Sun, the prospective constraints from future neutrino telescopes and ton-sized direct detection experiments, and the possible signatures at the Large Hadron Collider and International Linear Collider.Comment: 32 pages, 10 figures; version to appear on JHE

Spin Measurements in Cascade Decays at the LHC

We systematically study the possibility of determining the spin of new particles after their discovery at the LHC. We concentrate on angular correlations in cascade decays. Motivated by constraints of electroweak precision tests and the potential of providing a Cold Dark Matter candidate, we focus on scenarios of new physics in which some discrete symmetry guarantees the existence of stable neutral particles which escape the detector. More specifically, we compare supersymmetry with another generic scenario in which new physics particles have the same spin as their Standard Model partners. A survey of possibilities of observing spin correlations in a broad range of decay channels is carried out, with interesting ones identified. Rather than confining ourselves to one "collider friendly" benchmark point (such as SPS1a), we describe the parameter region in which any particular decay channel is effective. We conduct a more detailed study of chargino's spin determination in the decay channel $\tilde{q}\to q + \tilde{C}^\pm \to q + W^\pm + LSP$. A scan over the chargino and neutralino masses is performed. We find that as long as the spectrum is not too degenerate the prospects for spin determination in this channel are rather good.Comment: 36 pages, references added, 1 figure modifie

Measuring Black Hole Spin using X-ray Reflection Spectroscopy

I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009

Dagger Categories of Tame Relations

Within the context of an involutive monoidal category the notion of a comparison relation is identified. Instances are equality on sets, inequality on posets, orthogonality on orthomodular lattices, non-empty intersection on powersets, and inner product on vector or Hilbert spaces. Associated with a collection of such (symmetric) comparison relations a dagger category is defined with "tame" relations as morphisms. Examples include familiar categories in the foundations of quantum mechanics, such as sets with partial injections, or with locally bifinite relations, or with formal distributions between them, or Hilbert spaces with bounded (continuous) linear maps. Of one particular example of such a dagger category of tame relations, involving sets and bifinite multirelations between them, the categorical structure is investigated in some detail. It turns out to involve symmetric monoidal dagger structure, with biproducts, and dagger kernels. This category may form an appropriate universe for discrete quantum computations, just like Hilbert spaces form a universe for continuous computation