Two chemically similar stellar overdensities on opposite sides of the plane of the Galaxy

Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these interactions in the form of stellar streams, substructures, and chemically distinct stellar components. The impact of dwarf galaxy mergers on the content and morphology of the Galactic disk is still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups, which may have extragalactic origin. However, there is mounting evidence that stellar overdensities at the outer disk/halo interface could have been caused by the interaction of a dwarf galaxy with the disk. Here we report detailed spectroscopic analysis of 14 stars drawn from two stellar overdensities, each lying about 5 kiloparsecs above and below the Galactic plane - locations suggestive of association with the stellar halo. However, we find that the chemical compositions of these stars are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way disk stars. This study hence provides compelling evidence that these stars originate from the disk and the overdensities they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.Comment: accepted for publication in Natur

SUSY Splits, But Then Returns

We study the phenomenon of accidental or "emergent" supersymmetry within gauge theory and connect it to the scenarios of Split Supersymmetry and Higgs compositeness. Combining these elements leads to a significant refinement and extension of the proposal of Partial Supersymmetry, in which supersymmetry is broken at very high energies but with a remnant surviving to the weak scale. The Hierarchy Problem is then solved by a non-trivial partnership between supersymmetry and compositeness, giving a promising approach for reconciling Higgs naturalness with the wealth of precision experimental data. We discuss aspects of this scenario from the AdS/CFT dual viewpoint of higher-dimensional warped compactification. It is argued that string theory constructions with high scale supersymmetry breaking which realize warped/composite solutions to the Hierarchy Problem may well be accompanied by some or all of the features described. The central phenomenological considerations and expectations are discussed, with more detailed modelling within warped effective field theory reserved for future work.Comment: 29 pages. Flavor and CP constraints on left-right symmetric structure briefly discussed. References adde

The Custodial Randall-Sundrum Model: From Precision Tests to Higgs Physics

We reexamine the Randall-Sundrum (RS) model with enlarged gauge symmetry SU(2)_L x SU(2)_R x U(1)_X x P_LR in the presence of a brane-localized Higgs sector. In contrast to the existing literature, we perform the Kaluza-Klein (KK) decomposition within the mass basis, which avoids the truncation of the KK towers. Expanding the low-energy spectrum as well as the gauge couplings in powers of the Higgs vacuum expectation value, we obtain analytic formulas which allow for a deep understanding of the model-specific protection mechanisms of the T parameter and the left-handed Z-boson couplings. In particular, in the latter case we explain which contributions escape protection and identify them with the irreducible sources of P_LR symmetry breaking. We furthermore show explicitly that no protection mechanism is present in the charged-current sector confirming existing model-independent findings. The main focus of the phenomenological part of our work is a detailed discussion of Higgs-boson couplings and their impact on physics at the CERN Large Hadron Collider. For the first time, a complete one-loop calculation of all relevant Higgs-boson production and decay channels is presented, incorporating the effects stemming from the extended electroweak gauge-boson and fermion sectors.Comment: 74 pages, 13 figures, 3 tables. v2: Matches version published in JHE

Suppressing Electroweak Precision Observables in 5D Warped Models

We elaborate on a recently proposed mechanism to suppress large contributions to the electroweak precision observables in five dimensional (5D) warped models, without the need for an extended 5D gauge sector. The main ingredient is a modification of the AdS metric in the vicinity of the infrared (IR) brane corresponding to a strong deviation from conformality in the IR of the 4D holographic dual. We compute the general low energy effective theory of the 5D warped Standard Model, emphasizing additional IR contributions to the wave function renormalization of the light Higgs mode. We also derive expressions for the S and T parameters as a function of a generic 5D metric and zero-mode wave functions. We give an approximate formula for the mass of the radion that works even for strong deviation from the AdS background. We proceed to work out the details of an explicit model and derive bounds for the first KK masses of the various bulk fields. The radion is the lightest new particle although its mass is already at about 1/3 of the mass of the lightest resonances, the KK states of the gauge bosons. We examine carefully various issues that can arise for extreme choices of parameters such as the possible reintroduction of the hierarchy problem, the onset of nonperturbative physics due to strong IR curvature or the creation of new hierarchies near the Planck scale. We conclude that a KK scale of 1 TeV is compatible with all these constraints.Comment: 44 pages, 11 figures, references adde

Flavour Physics in the Soft Wall Model

We extend the description of flavour that exists in the Randall-Sundrum (RS) model to the soft wall (SW) model in which the IR brane is removed and the Higgs is free to propagate in the bulk. It is demonstrated that, like the RS model, one can generate the hierarchy of fermion masses by localising the fermions at different locations throughout the space. However, there are two significant differences. Firstly the possible fermion masses scale down, from the electroweak scale, less steeply than in the RS model and secondly there now exists a minimum fermion mass for fermions sitting towards the UV brane. With a quadratic Higgs VEV, this minimum mass is about fifteen orders of magnitude lower than the electroweak scale. We derive the gauge propagator and despite the KK masses scaling as $m_n^2\sim n$, it is demonstrated that the coefficients of four fermion operators are not divergent at tree level. FCNC's amongst kaons and leptons are considered and compared to calculations in the RS model, with a brane localised Higgs and equivalent levels of tuning. It is found that since the gauge fermion couplings are slightly more universal and the SM fermions typically sit slightly further towards the UV brane, the contributions to observables such as $\epsilon_K$ and $\Delta m_K$, from the exchange of KK gauge fields, are significantly reduced.Comment: 33 pages, 15 figures, 5 tables; v2: references added; v3: modifications to figures 4,5 and 6. version to appear in JHE

The Fermion Mass Hierarchy in Models with Warped Extra Dimensions and a Bulk Higgs

The phenomenological implications of allowing the Higgs to propagate in both AdS${}_5$ and a class of asymptotically AdS spaces are considered. Without tuning, the vacuum expectation value (VEV) of the Higgs is peaked towards the IR tip of the space and hence such a scenario still offers a potential resolution to the gauge-hierarchy problem. When the exponent of the Higgs VEV is approximately two and one assumes order one Yukawa couplings, then the fermion Dirac mass term is found to range from $\sim 10^{-5}$ eV to $\sim 200$ GeV in approximate agreement with the observed fermion masses. However, this result is sensitive to the exponent of the Higgs VEV, which is a free parameter. This paper offers a number of phenomenological and theoretical motivations for considering an exponent of two to be the optimal value. In particular, the exponent is bounded from below by the Breitenlohner-Freedman bound and the requirement that the dual theory resolves the gauge hierarchy problem. While, in the model considered, if the exponent is too large, electroweak symmetry may not be broken. In addition, the holographic method is used to demonstrate, in generality, that the flatter the Higgs VEV, the smaller the contribution to the electroweak $T$ parameter. In addition, the constraints from a large class of gauge mediated and scalar mediated flavour changing neutral currents, will be at minimal values for flatter Higgs VEVs. Some initial steps are taken to investigate the physical scalar degrees of freedom that arise from a mixing between the $W_5/Z_5$ components and the Higgs components.Comment: 34 pages, 20 figures, 1 table; v3: matches version to be published in JHE

Diet quality is positively associated with 100% fruit juice consumption in children and adults in the United States: NHANES 2003-2006

<p>Abstract</p> <p>Background</p> <p>One hundred percent fruit juice (100% FJ) has been viewed by some as a sweetened beverage with concerns about its effect on weight. Little regard has been given to the contribution of 100% FJ to diet quality.</p> <p>Methods</p> <p>In this study data from the 2003-2006 National Health and Nutrition Examination Survey were used to examine the association of 100% FJ consumption with diet quality in participants 2-5 years of age (y) (n = 1665), 6-12 y (n = 2446), 13-18 y (n = 3139), and 19+y (n = 8861). Two 24-hour dietary recalls were used to determine usual intake using the National Cancer Institute method. Usual intake, standard errors, and regression analyses (juice independent variable and Healthy Eating Index-2005 [HEI-2005] components were dependent variables), using appropriate covariates, were determined using sample weights.</p> <p>Results</p> <p>The percentage of participants 2-5 y, 6-12 y, 13-18 y, and 19+y that consumed 100% FJ was 71%, 57%, 45%, and 62%, respectively. Usual intake of 100% FJ (ounce [oz]/day) among the four age groups was: 5.8 ± 0.6, 2.6 ± 0.4, 3.7 ± 0.4, and 2.4 ± 0.2 for those in age groups 2-5 y, 6-12 y, 13-18 y, and 19+y, respectively. Consumption of 100% FJ was associated with higher energy intake in 6-12 y, 13-18 y, and 19+y; and higher total, saturated, and discretionary fats in 13-18 y participants. Consumption of 100% FJ was associated with higher total HEI-2005 scores in all age groups (< 0.0001). In 100% FJ consumers, total and whole fruit consumption was higher and intake of added sugars was lower in all age groups.</p> <p>Conclusions</p> <p>Usual intake of 100% FJ consumption exceeded MyPyramid recommendations for children 2-5 y, but was associated with better diet quality in all age groups and should be encouraged in moderation as part of a healthy diet.</p

Measures of the Consumer Food Store Environment: A Systematic Review of the Evidence 2000–2011

Description of the consumer food environment has proliferated in publication. However, there has been a lack of systematic reviews focusing on how the consumer food environment is associated with the following: (1) neighborhood characteristics; (2) food prices; (3) dietary patterns; and (4) weight status. We conducted a systematic review of primary, quantitative, observational studies, published in English that conducted an audit of the consumer food environment. The literature search included electronic, hand searches, and peer-reviewed from 2000 to 2011. Fifty six papers met the inclusion criteria. Six studies reported stores in low income neighborhoods or high minority neighborhoods had less availability of healthy food. While, four studies found there was no difference in availability between neighborhoods. The results were also inconsistent for differences in food prices, dietary patterns, and weight status. This systematic review uncovered several key findings. (1) Systematic measurement of determining availability of food within stores and store types is needed; (2) Context is relevant for understanding the complexities of the consumer food environment; (3) Interventions and longitudinal studies addressing purchasing habits, diet, and obesity outcomes are needed; and (4) Influences of price and marketing that may be linked with why people purchase certain items