2,814 research outputs found

    Vevacious: A Tool For Finding The Global Minima Of One-Loop Effective Potentials With Many Scalars

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    Several extensions of the Standard Model of particle physics contain additional scalars implying a more complex scalar potential compared to that of the Standard Model. In general these potentials allow for charge and/or color breaking minima besides the desired one with correctly broken SU(2)_L times U(1)_Y . Even if one assumes that a metastable local minimum is realized, one has to ensure that its lifetime exceeds that of our universe. We introduce a new program called Vevacious which takes a generic expression for a one-loop effective potential energy function and finds all the tree-level extrema, which are then used as the starting points for gradient-based minimization of the one-loop effective potential. The tunneling time from a given input vacuum to the deepest minimum, if different from the input vacuum, can be calculated. The parameter points are given as files in the SLHA format (though is not restricted to supersymmetric models), and new model files can be easily generated automatically by the Mathematica package SARAH. This code uses HOM4PS2 to find all the minima of the tree-level potential, PyMinuit to follow gradients to the minima of the one-loop potential, and CosmoTransitions to calculate tunneling times.Comment: 44 pages, 1 figure, manual for publicly available software, v2 corresponds to version accepted for publication in EPJC [clearer explanation of scale dependence and region of validity, explicit mention that SLHA files should have blocks matching those expected by model files, updated references

    Constraining the Natural MSSM through tunneling to color-breaking vacua at zero and non-zero temperature

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    We re-evaluate the constraints on the parameter space of the minimal supersymmetric standard model from tunneling to charge- and/or color-breaking minima, taking into account thermal corrections. We pay particular attention to the region known as the Natural MSSM, where the masses of the scalar partners of the top quarks are within an order of magnitude or so of the electroweak scale. These constraints arise from the interaction between these scalar tops and the Higgs fields, which allows the possibility of parameter points having deep charge- and color-breaking true vacua. In addition to requiring that our electro-weak-symmetry-breaking, yet QCD- and electromagnetism-preserving vacuum has a sufficiently long lifetime at zero temperature, also demanding stability against thermal tunneling further restricts the allowed parameter space.Comment: 7 pages, 2 figures, software available from http://vevacious.hepforge.org/ - version 2 matches that accepted for publication in Phys. Lett.

    The new control system of the SPS target sector

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    The SPS, the Super Proton Synchrotron at CERN, is an accelerator originally designed and commissioned in 1976 for protons. The control system of the SPS target stations, beam absorbers and other aperture limiting devices was developed in the seventies. It was mainly based on home made electronics and equipment dependent software. With time, this electronics has become obsolete, difficult to maintain in operation and not suitable for integration into a modern control system. In 1997, a project was set up to modernise the electronics and the related software. The new control system is largely based on standard industrial hardware and software components. SIEMENS Simatic S7-300 programmable logic controllers have been used as equipment controllers and connected through PROFIBUS to a Windows-NT front-end PC running the SIEMENS WinCC SCADA package which acts as local controller and remote access gateway. This fully industrial solution has been successfully integrated into the actual SPS accelerator control infrastructure and is open to other industrial communication protocols. The design, development and realisation of the selected solution have been outsourced to industry

    Socio-economic variations in anticipated adverse reactions to testing HPV positive: Implications for the introduction of primary HPV-based cervical screening

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    Some cervical cancer screening programmes are replacing cytology with human papillomavirus (HPV) DNA testing as the primary screening test. Concerns have been previously raised around the potential psychosocial impact of testing positive for HPV. We analysed socio-economic variations in anticipated adverse reactions to testing positive for HPV in women of screening age in the general population. A questionnaire was mailed to a random sample of 5553 women aged 20-64 in 2010, selected through primary care in Ireland. This included questions on: socio-economics; HPV knowledge; and women's anticipated adverse psychosocial responses to testing HPV positive (shame, anxiety, stigma and worry). Multivariable linear regression was used to identify socio-economic factors significantly associated with each anticipated adverse reaction. The response rate was 62% (n = 3470). In multivariate analyses, having only attained primary level education were significantly associated with higher mean scores for all four adverse outcomes. Religion was significantly associated with all four adverse outcomes. Age was associated with anxiety and worry; younger women (<30 years) had the highest mean scores. Being married/cohabiting was significantly associated with significantly lower shame and worry scores. Not working was significantly associated with higher mean anxiety and worry scores. Our large population-based survey found significant socio-economic variations in anticipated adverse reactions to testing HPV positive. In order to minimise possible negative impacts on screening uptake and alleviate potential adverse psychological effects of HPV-based screening on women, screening programmes may need to develop specific messages around HPV infection and HPV screening that target certain subgroups of women

    A new method of prenatal alcohol classification accounting for dose, pattern, and timing of exposure: Improving our ability to examine fetal effects from low to moderate exposure

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    Background: When examining the association between prenatal alcohol exposure and fetal effects, the timing and intensity of exposure have been ignored in epidemiological studies. The effect of using dose, pattern and timing of consumption (“composite” method) was investigated in this study, to examine the association between prenatal alcohol exposure and fetal effects. Methods: The composite method resulted in six categories of exposure (abstinent, low, moderate, binge <weekly, binge 1–2×/week and heavy). The odds of language delay and child behaviour problems were calculated for the composite method and then compared with an analysis using averaged estimates of <1 and 1+ drinks per day and with stratification by quantity ignoring dose per occasion. Data used for the analyses were from a 10% random sample of non-Indigenous women delivering a live infant in Western Australia (1995–1997). Participants from the 1995-1996 cohort were invited to participate in an 8-year longitudinal survey (78% response rate n=2224; 85% were followed-up at 2 years, 73% at 5 years and 61% at 8 years). Results: The effect of moderate and binge levels of exposure was only evident with the composite method; anxiety/depression following first-trimester moderate exposure (OR 2.24, 95% CI 1.16 to 4.34), and following late pregnancy moderate (aggressive behaviour OR 1.93, 95% CI 0.91 to 4.09) and binge (language delay OR 3.00, 95% CI 0.90 to 9.93) exposures. Results for heavy levels of exposure were similar with each method. The estimates for late pregnancy were imprecise due to small numbers. Conclusion: The composite method of classification more closely reflects real-life drinking patterns and better discriminates maternal drinking than the other methods, particularly low, moderate and binge levels
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