Probing New Physics from Top-charm Associated Productions at Linear Colliders

The top-charm associated productions via $e^+ e^-$, $e^- \gamma$ and $\gamma \gamma$ collisions at linear colliders, which are extremely suppressed in the Standard Model (SM), could be significantly enhanced in some extensions of the SM. In this article we calculate the full contribution of the topcolor-assisted technicolor (TC2) to these productions and then compare the results with the existing predictions of the SM, the general two-Higgs-doublet model and the Minimal Supersymmetric Model. We find that the TC2 model predicts much larger production rates than other models and the largest-rate channel is $\gamma \gamma \to t \bar{c}$, which exceeds 10 fb for a large part of the parameter space. From the analysis of the observability of such productions at the future linear colliders, we find that the predictions of the TC2 model can reach the observable level for a large part of the parameter space while the predictions of other models are hardly accessible.Comment: discussions added (version in Eur. Phys. J. C

The impact of XENON100 and the LHC on Supersymmetric Dark Matter

The effect of 2010 and 2011 LHC data are discussed in connection to the potential for the direct detection of supersymmetric dark matter. The impact of the recent XENON100 results are contrasted to these predictions.Comment: 14 pages, 23 figures, To be published in the Proceedings of the 7th DSU Conference, Beijing Chin

Factors impacting antiretroviral therapy adherence among human immunodeficiency virus-positive adolescents in Sub-Saharan Africa: a systematic review

© 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.Objectives: Eighty-two percent of human immunodeficiency virus (HIV)–positive adolescents live in Sub-Saharan Africa (SSA). Despite the availability of antiretroviral therapy (ART), adherence levels are suboptimal, leading to poor outcomes. This systematic review investigated factors impacting ART adherence among adolescents in SSA, including religious beliefs and intimate relationships. Methods: A systematic review was conducted between June and August 2016 using eight electronic databases, including Cochrane and PubMed. Published, ongoing and unpublished research, conducted in SSA from 2004 to 2016, was identified and thematic analysis was used to summarise findings. Results: Eleven studies from eight SSA countries, published in English between 2011 and 2016, reported on factors impacting ART adherence among adolescents living with HIV (ALHIV). Forty-four barriers and 29 facilitators to adherence were identified, representing a complex web of factors. The main barriers were stigma, ART side-effects, lack of assistance and forgetfulness. Facilitators included caregiver support, peer support groups and knowledge of HIV status. Conclusions: Stigma reflects difficult relations between ALHIV and their HIV-negative peers and adults. Most interventions target only those with HIV, suggesting a policy shift towards the wider community could be beneficial. Recommendations include engaging religious leaders and schools to change negative societal attitudes. Limitations of the review include the urban settings and recruitment of predominantly vertically infected participants in most included studies. Therefore, the findings cannot be extrapolated to ALHIV residing in rural locations or horizontally infected ALHIV, highlighting the need for further research in those areas.Peer reviewedFinal Accepted Versio

On the market impact of wind energy forecasts

This paper presents an analysis of how day-ahead electricity spot prices are affected by day-ahead wind power forecasts. Demonstration of this relationship is given as a test case for the Western Danish price area of the Nord Pool’s Elspot market. Impact on the average price behaviour is investigated as well as that on the distributional properties of the price. By using a non-parametric regression model to assess the effects of wind power forecasts on the average behaviour, the non-linearities and time variations in the relationship are captured well and the effects are shown to be quite substantial. Furthermore, by evaluating the distributional properties of the spot prices under different scenarios, the impact of the wind power forecasts on the price distribution is proved to be considerable. The conditional price distribution is moreover shown to be non-Gaussian. This implies that forecasting models for electricity spot prices for which parameters are estimated by a least squares techniques will not have Gaussian residuals. Hence the widespread assumption of Gaussian residuals from electricity spot price models is shown to be inadequate for these model types. The revealed effects are likely to be observable and qualitatively similar in other day-ahead electricity markets significantly penetrated by wind power

Supersymmetry Without Prejudice

We begin an exploration of the physics associated with the general CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY breaking parameters in this scenario are chosen so as to satisfy all existing experimental and theoretical constraints assuming that the WIMP is a conventional thermal relic, ie, the lightest neutralino. We scan this parameter space twice using both flat and log priors for the soft SUSY breaking mass parameters and compare the results which yield similar conclusions. Detailed constraints from both LEP and the Tevatron searches play a particularly important role in obtaining our final model samples. We find that the pMSSM leads to a much broader set of predictions for the properties of the SUSY partners as well as for a number of experimental observables than those found in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of models can easily lead to atypical expectations for SUSY signals at the LHC.Comment: 61 pages, 24 figs. Refs., figs, and text added, typos fixed; This version has reduced/bitmapped figs. For a version with better figs please go to http://www.slac.stanford.edu/~rizz

Dynamic analysis of the EBR-II plant with the DSNP-ND simulation package

Development and initial testing have been completed for a special version of the DSNP simulation language software package, DSNP-ND, which simulates EBR-II based on the models of the primary system components used in the NATDEMO program. Preliminary results are included for a comparison with an original NATDEMO prediction for the SHRT-45 transient. 7 refs

The pole structure of the unitary, crossing symmetric low energy ππ\pi\pi scattering amplitudes

The pole structure of the low energy $\pi\pi$ scattering amplitudes is studied using a proper chiral unitarization method combined with crossing symmetry and the low energy phase shift data. It is found that the $\sigma$ pole position is at $M_\sigma=470\pm 50MeV$, $\Gamma_\sigma=570\pm 50MeV$. The existence of the virtual state pole in the IJ=20 channel is reconfirmed. Various threshold parameters are estimated and are found in general in good agreement with the results obtained from the Roy equation analyses.Comment: Minor corrections made and references added. Final version accepted for publication as JHEP02(2005)04